COA — Certified Ophthalmic Assistant Exam — Questions and Answers

Question 1: An automated refractor measures a young, asymptomatic patient's prescription as -3.00 D sphere in both eyes. However, a subsequent cycloplegic refraction reveals a true prescription of -0.75 D sphere. What is the MOST likely cause for this significant discrepancy?

Accommodative spasm (Correct answer)
Instrument miscalibration
Poor patient fixation
Corneal surface irregularity

Correct answer: Accommodative spasm

Young patients can exert a significant amount of focusing effort (accommodation), especially when looking into a machine. This accommodative spasm causes the eye's crystalline lens to increase its power, leading the autorefractor to measure more myopia than is actually present. A cycloplegic drop temporarily paralyzes the focusing muscle, revealing the true, relaxed refractive state.

Question 2: Which cranial nerve controls the majority of extraocular muscles?

CN V (trigeminal)
CN III (oculomotor) (Correct answer)
CN VI (abducens)
CN IV (trochlear)

Correct answer: CN III (oculomotor)

CN III controls the superior rectus, inferior rectus, medial rectus, inferior oblique, and levator palpebrae superioris.

Question 3: What is the primary advantage of silicone hydrogel contact lenses over conventional hydrogel lenses?

They are less expensive to manufacture
They have significantly higher oxygen transmissibility (Dk/t) (Correct answer)
They require no cleaning or disinfection
They provide better UV protection

Correct answer: They have significantly higher oxygen transmissibility (Dk/t)

Silicone hydrogel lenses have much higher oxygen transmissibility (Dk/t) than conventional hydrogels, allowing more oxygen to reach the cornea and reducing hypoxia-related complications.

Question 4: What is the primary purpose of performing retinoscopy?

Photograph the fundus
Measure corneal thickness
Measure intraocular pressure
Determine refractive error objectively (Correct answer)

Correct answer: Determine refractive error objectively

Retinoscopy is an objective technique to determine a patient's refractive error by observing the light reflex.

Question 5: A patient complains of giant papillary conjunctivitis (GPC) after months of soft contact lens wear. What is the most likely cause?

Corneal neovascularization from lens hypoxia
Mechanical irritation and immune response to lens deposits or the lens edge (Correct answer)
Bacterial infection from contaminated lens case
Lens dehydration causing anterior surface dryness

Correct answer: Mechanical irritation and immune response to lens deposits or the lens edge

GPC (also called contact lens-induced papillary conjunctivitis, CLPC) is caused by repeated mechanical trauma from the lens edge and immune reaction to protein deposits on the lens surface, leading to papillae on the upper tarsal conjunctiva.

Question 6: Which class of topical medications is the MOST commonly prescribed first-line treatment for primary open-angle glaucoma?

Prostaglandin analogues (e.g., latanoprost, bimatoprost) (Correct answer)
Carbonic anhydrase inhibitors (e.g., dorzolamide)
Alpha-2 agonists (e.g., brimonidine)
Beta-blockers (e.g., timolol)

Correct answer: Prostaglandin analogues (e.g., latanoprost, bimatoprost)

Prostaglandin analogues are the most commonly used first-line medications for POAG due to their once-daily dosing, potent IOP reduction (25–35%), and favorable side effect profile compared to other classes.

Question 7: What is the purpose of a pinhole occluder during visual acuity testing?

To assess peripheral visual field
To determine whether reduced acuity is due to refractive error (Correct answer)
To occlude the fellow eye during monocular testing
To measure the size of the pupil

Correct answer: To determine whether reduced acuity is due to refractive error

A pinhole occluder limits incoming light to the central paraxial rays, bypassing refractive error. If vision improves with pinhole, the reduction is likely refractive; if it does not improve, pathology (media opacity, retinal or optic nerve disease) should be suspected.

Question 8: The Amsler grid is used to detect central visual field defects. A patient reports that the central dot disappears and surrounding lines appear wavy. This finding is MOST consistent with:

Peripheral retinal detachment
Optic neuritis
Macular pathology such as age-related macular degeneration (Correct answer)
Elevated intraocular pressure

Correct answer: Macular pathology such as age-related macular degeneration

The Amsler grid tests the central 20 degrees of the visual field. Wavy or distorted lines (metamorphopsia) and a central scotoma are classic findings in macular diseases such as AMD, macular edema, or epiretinal membrane.

Question 9: When obtaining a patient history, which question is MOST important to ask when a patient reports sudden painless vision loss in one eye?

Have you had any recent head trauma or vascular events? (Correct answer)
When did you last have your glasses updated?
Do you wear contact lenses?
Do you have a family history of glaucoma?

Correct answer: Have you had any recent head trauma or vascular events?

Sudden painless vision loss in one eye is a red flag for vascular events such as central retinal artery occlusion, retinal vein occlusion, or stroke. Asking about recent vascular events (TIA, hypertension crises) and trauma helps triage urgency and guides the physician.

Question 10: What is orthokeratology (ortho-k)?

An exercise regimen to strengthen extraocular muscles
A method of measuring corneal curvature with a keratometer
Surgical reshaping of the cornea using a laser
Use of specially designed rigid lenses worn overnight to temporarily reshape the cornea (Correct answer)

Correct answer: Use of specially designed rigid lenses worn overnight to temporarily reshape the cornea

Orthokeratology involves wearing specially designed rigid contact lenses overnight to temporarily flatten the cornea, reducing myopia during the day without lenses.

Question 11: Which item is not a classification of fixation?

Central
Steady
Maintained
Primary (Correct answer)

Correct answer: Primary

Explanation: "Primary" is not a classification of fixation. Central, steady, and maintained fixation refer to different aspects of how the eyes focus on an object. Central fixation refers to focusing on the central point of an object, steady fixation means maintaining focus without wandering, and maintained fixation implies continued focus over time.

Question 12: The state of pupillary contraction is known as:

Photophobia
Mydriasis
Anisocoria
Miosis (Correct answer)

Correct answer: Miosis

Explanation: Miosis refers to the state of pupillary constriction, where the pupil is constricted or smaller than normal.

Question 13: What does 'Dk' represent in contact lens terminology?

The dioptric power of the contact lens
The lens diameter in kilograms
The dissolving constant of the cleaning solution
The oxygen permeability of the lens material (Correct answer)

Correct answer: The oxygen permeability of the lens material

Dk is the oxygen permeability of a contact lens material, where D is the diffusion coefficient and k is the solubility coefficient of oxygen in the material.

Question 14: The choroid layer primarily provides nutrition to which ocular structure?

Outer retinal layers including photoreceptors (Correct answer)
The corneal stroma
Vitreous humor
Anterior segment tissues

Correct answer: Outer retinal layers including photoreceptors

The choriocapillaris supplies oxygen and nutrients to the photoreceptors and retinal pigment epithelium via diffusion.

Question 15: A patient calls stating they suddenly see 'flashing lights and a curtain' over the vision in their right eye. Which of the following is the MOST appropriate action for the ophthalmic assistant to take?

Schedule the patient for the next available routine appointment.
Advise the patient to monitor the symptoms and call back if they worsen.
Instruct the patient to come to the office for an emergency evaluation immediately. (Correct answer)
Document the call and place it on the physician's desk for review at the end of the day.

Correct answer: Instruct the patient to come to the office for an emergency evaluation immediately.

The symptoms of flashing lights and a curtain in the vision are classic signs of a potential retinal tear or detachment, which is an ocular emergency requiring immediate evaluation and possible treatment to prevent permanent vision loss.

Question 16: A patient with a history of severe asthma and bradycardia is being evaluated for glaucoma. Which class of topical medication is generally contraindicated for this patient?

Alpha-adrenergic agonists
Carbonic anhydrase inhibitors
Beta-blockers (Correct answer)
Prostaglandin analogs

Correct answer: Beta-blockers

Topical beta-blockers, such as timolol, can be absorbed systemically and may cause bronchospasm and a slowed heart rate (bradycardia). Therefore, they are contraindicated in patients with conditions like asthma, COPD, or significant cardiac issues like bradycardia.

Question 17: The trabecular meshwork is clinically significant because it:

Controls the pupillary light reflex
Produces the majority of aqueous humor
Is the primary drainage site for aqueous humor (Correct answer)
Provides structural support to the crystalline lens

Correct answer: Is the primary drainage site for aqueous humor

The trabecular meshwork drains approximately 80–90% of aqueous humor into Schlemm's canal, and its dysfunction elevates IOP.

Question 18: A Certified Ophthalmic Assistant is performing confrontation visual field testing on a patient. The assistant and patient are seated facing each other. To properly test the patient's right eye, the assistant should instruct the patient to cover their left eye and the assistant should cover their:

Right eye, looking at the patient's left eye
Right eye, looking at the patient's right eye (Correct answer)
Left eye, looking at the patient's nose
Left eye, looking at the patient's right eye

Correct answer: Right eye, looking at the patient's right eye

Confrontation visual field testing compares the patient's peripheral vision to the examiner's. To test the patient's right eye, the patient covers their left eye. The examiner then covers their own right eye (the one directly opposite the patient's covered eye) and instructs the patient to look at the examiner's open (left) eye. This allows for a direct comparison of the temporal field of the patient's right eye and the nasal field of the examiner's left eye, and vice versa.

Question 19: What is the most appropriate initial management for a contact lens wearer who presents with a red, painful eye and a central corneal infiltrate?

Immediately discontinue lens wear and refer to a physician for evaluation of possible microbial keratitis (Correct answer)
Refit with a daily disposable lens
Prescribe artificial tears and resume lens wear in 24 hours
Switch to hydrogen peroxide disinfection and continue lens wear

Correct answer: Immediately discontinue lens wear and refer to a physician for evaluation of possible microbial keratitis

A central corneal infiltrate in a contact lens wearer is a potential sight-threatening emergency, and lens wear must be stopped immediately with urgent referral to rule out microbial keratitis.

Question 20: A keratometry reading is 44.00 D @ 180 / 46.00 D @ 090. When fitting a spherical soft contact lens, the effective lens power on the eye will primarily correct which component?

The spherical equivalent, leaving residual astigmatism uncorrected (Correct answer)
Only the steepest meridian power
The full astigmatic correction with no residual error
Only the flattest meridian power

Correct answer: The spherical equivalent, leaving residual astigmatism uncorrected

Spherical soft lenses drape over the cornea and correct mainly the spherical equivalent of the refraction; the corneal astigmatism is largely uncorrected, leaving residual astigmatism.

Question 21: The retinal pigment epithelium (RPE) performs which critical daily function?

Phagocytoses shed photoreceptor outer segments (Correct answer)
Regulates aqueous humor secretion
Maintains corneal clarity through fluid pumping
Produces the vitreous humor gel

Correct answer: Phagocytoses shed photoreceptor outer segments

The RPE phagocytoses and recycles the outer segment discs shed daily by rod and cone photoreceptors to maintain retinal health.

Question 22: Which of the following is an essential component of the past ocular history?

Patient's occupation and hobbies.
A list of the patient's food allergies.
History of diabetes and hypertension.
Previous eye surgeries or significant eye trauma. (Correct answer)

Correct answer: Previous eye surgeries or significant eye trauma.

The past ocular history specifically pertains to the patient's eyes. Previous surgeries (like cataract or refractive surgery) and trauma are critical pieces of information. Systemic diseases like diabetes belong in the past medical history, occupation is part of the social history, and allergies have their own dedicated section.

Question 23: Corneal topography is most useful for detecting:

Irregular corneal surface changes such as keratoconus (Correct answer)
Anterior chamber angle anatomy
Retinal thickness changes
Intraocular pressure distribution

Correct answer: Irregular corneal surface changes such as keratoconus

Corneal topography maps the entire corneal surface curvature, revealing irregularities like keratoconus or post-surgical changes.

Question 24: Which of the following tests is used to evaluate ocular alignment by observing the location of the corneal light reflex?

Worth 4-Dot Test
Cover-Uncover Test
Titmus Test
Hirschberg Test (Correct answer)

Correct answer: Hirschberg Test

The Hirschberg test assesses ocular alignment by observing the reflection of a light source on the corneas. In a properly aligned patient, the reflection should be centered in both pupils. An asymmetric reflex indicates a possible strabismus.

Question 25: When performing Amsler grid testing on a patient, which of the following instructions is most critical for an accurate result?

"Hold the grid at a comfortable reading distance, about 12-14 inches away." (Correct answer)
"Focus on the entire grid at once to see the overall pattern."
"Remove your reading glasses to avoid any distortion they might cause."
"Test both eyes together first, then check each eye individually."

Correct answer: "Hold the grid at a comfortable reading distance, about 12-14 inches away."

The Amsler grid is designed to test the central 20 degrees of the visual field at a specific distance. Holding the grid at a consistent reading distance (typically 12-14 inches or 30 cm) is essential for the test's standardization and accuracy. Testing must be done monocularly (one eye at a time) while wearing any near correction (reading glasses) the patient normally uses. The patient should fixate on the central dot, not scan the entire grid.

Question 26: An ophthalmic assistant is checking the calibration of a Goldmann tonometer using the supplied calibration bar. At the '0' setting, what should happen when the dial is turned slightly forward (e.g., to +0.05)?

The measurement drum should lock into place.
The feeler arm should fall toward the examiner.
The feeler arm should fall toward the patient. (Correct answer)
The feeler arm should remain perfectly still.

Correct answer: The feeler arm should fall toward the patient.

To verify the calibration of a Goldmann tonometer at the 0 position, the feeler arm should move freely. When the dial is turned slightly forward (clockwise, toward a positive value), the arm should fall away from the examiner and toward the patient. If it moves toward the examiner or doesn't move, it indicates an inaccuracy.

Question 27: Which cannot be used for color vision testing?

Hardy-Rand-Ritter plates
Pseudoisochromatic plates
Fly test (Correct answer)
Nagal anomaloscope

Correct answer: Fly test

Explanation: The fly test is not typically used for color vision testing. Options A, B, and C are commonly used methods for assessing color vision. Pseudoisochromatic plates, such as the Ishihara plates, are used for screening color vision deficiencies. Hardy-Rand-Ritter plates are used for testing acquired color vision defects. The Nagel anomaloscope is used for diagnosing and quantifying congenital color vision deficiencies.

Question 28: A patient's near vision is tested with a near card and documented as J3 at 40 cm. What does this indicate?

The patient needs a +3.00 add for near vision
The patient can read Jaeger size 3 text at 40 cm without correction (Correct answer)
The patient has 3 diopters of accommodative amplitude
The patient reads at 3 words per minute at 40 cm

Correct answer: The patient can read Jaeger size 3 text at 40 cm without correction

The Jaeger (J) notation is a near vision scale using a series of text paragraphs of increasing size. J3 indicates the patient can read Jaeger size 3 text, a moderately small print size, at the specified test distance of 40 cm.

Question 29: Gonioscopy is performed to directly evaluate which ocular structure?

The anterior chamber drainage angle (Correct answer)
Vitreous humor clarity
The ciliary muscle during accommodation
The posterior pole of the retina

Correct answer: The anterior chamber drainage angle

Gonioscopy uses a contact lens with mirrors to allow direct visualization of the iridocorneal angle — the drainage structure that cannot be seen directly due to total internal reflection at the corneal surface.

Question 30: The avascular cornea receives oxygen primarily from which sources?

The ophthalmic artery
Tear film and aqueous humor (Correct answer)
Vitreous humor
Conjunctival vessels

Correct answer: Tear film and aqueous humor

The cornea gets oxygen anteriorly from the tear film and posteriorly from the aqueous humor due to its avascularity.

Question 31: Which of the following is incorrect regarding the mad do rod test?

The tests can be used to measure vertical phobias at a distance.
The test can be used to measure vertical phobias in near
The test cannot be used to measure both vertical and horizontal photos at a distance and near. (Correct answer)
The test can be used to measure both verbal and horizontal phobias at a distance and near.

Correct answer: The test cannot be used to measure both vertical and horizontal photos at a distance and near.

Explanation: The Mallett unit (MA) is used to quantify the magnitude and direction of phorias in both vertical and horizontal planes at distance and near. Therefore, option A is incorrect; the test can be used to measure both vertical and horizontal phorias at a distance and near.

Question 32: Which structure produces the lipid (outer) layer of the tear film?

Meibomian glands of the eyelid (Correct answer)
Main lacrimal gland
Goblet cells of the conjunctiva
Accessory lacrimal glands of Krause

Correct answer: Meibomian glands of the eyelid

Meibomian glands are sebaceous glands within the tarsal plates that secrete the lipid layer to reduce tear evaporation.

Question 33: The amoric environment in the operating room is created by all steps below with the exception of the:

use of powdered gloves (Correct answer)
rinsing of instruments after use with saline
use of millipore filters
use of lint-free drapes

Correct answer: use of powdered gloves

Explanation: The use of powdered gloves is not conducive to creating an aseptic (or amoric) environment in the operating room because the powder can introduce particulate matter, potentially contaminating the surgical field. The other options—use of lint-free drapes, rinsing instruments with saline, and use of millipore filters—contribute to maintaining a sterile environment.

Question 34: Which common familial ocular disorder should you record during a patient's history?

Scholiosis
Keratoconus (Correct answer)
Hemophilia
Cholesteremia

Correct answer: Keratoconus

Explanation: Keratoconus is a common familial ocular disorder that affects the shape of the cornea and should be recorded during a patient's history. The other conditions listed are not primarily ocular disorders.

Question 35: When documenting the Chief Complaint (CC), the ophthalmic assistant should:

Interpret the patient's symptoms using proper medical terminology.
List all symptoms the patient has experienced in the last year.
Detail the suspected diagnosis based on the patient's description.
Record the primary reason for the visit in the patient's own words. (Correct answer)

Correct answer: Record the primary reason for the visit in the patient's own words.

The chief complaint should be a concise statement that documents the patient's primary reason for the visit, recorded verbatim in their own words to avoid misinterpretation.

Question 36: What is the primary diagnostic purpose of fluorescein angiography?

Evaluate retinal and choroidal circulation (Correct answer)
Determine refractive error
Assess intraocular pressure
Measure corneal thickness

Correct answer: Evaluate retinal and choroidal circulation

Fluorescein angiography documents retinal and choroidal blood flow by imaging intravenous fluorescent dye.

Question 37: Which instrument is used to measure corneal thickness (pachymetry)?

Autorefractor
Pachymeter (Correct answer)
Keratometer
Perimeter

Correct answer: Pachymeter

A pachymeter measures corneal thickness, which affects IOP accuracy and refractive surgery candidacy.

Question 38: Which of the following is a component of the Social History section in an ophthalmic history?

Use of topical glaucoma drops
Systemic hypertension
Current smoking status and occupation (Correct answer)
Amblyopia treated in childhood

Correct answer: Current smoking status and occupation

Social history includes lifestyle factors such as smoking status, alcohol use, occupation, and living situation. Smoking is a modifiable risk factor for AMD and other ocular conditions, making it clinically relevant to document.

Question 39: During Goldmann applanation tonometry, the fluorescein mires are observed to be very thick and wide. This is most likely to cause what type of error in the IOP measurement?

A falsely low reading
A falsely high reading (Correct answer)
An intermittent reading
No error, as mire thickness is irrelevant

Correct answer: A falsely high reading

Excessive fluorescein in the tear film creates thick mires. The width of the mire band adds to the area of applanation, meaning less force is required from the tonometer dial to align the inner edges. This leads the operator to record a pressure that is falsely high. Conversely, too little fluorescein (thin mires) can lead to a falsely low reading.

Question 40: Which type of contact lens is most appropriate for correcting irregular astigmatism caused by keratoconus?

Soft toric lens
Rigid gas-permeable lens (Correct answer)
Monovision soft lens
Daily disposable spherical soft lens

Correct answer: Rigid gas-permeable lens

Rigid gas-permeable (RGP) lenses vault over the irregular corneal surface and use the tear lens to neutralize irregular astigmatism, making them the preferred option for keratoconus.

Question 41: The macula lutea is characterized by which feature?

Absence of all photoreceptors
High concentration of cones and the fovea centralis (Correct answer)
Location in the nasal retina
High concentration of rod cells

Correct answer: High concentration of cones and the fovea centralis

The macula contains the highest cone density and the fovea centralis, providing the sharpest central vision.

Question 42: When recording color vision results from Ishihara testing, a patient correctly identifies 8 of 14 test plates. How should this be documented?

Color vision: Mild protan defect confirmed
Color vision: 8/14 plates correct (abnormal) (Correct answer)
Color vision: 57% accuracy — borderline
Color vision: Normal

Correct answer: Color vision: 8/14 plates correct (abnormal)

Results are documented as the number of plates correctly identified out of total plates tested. Normal typically requires correct identification of 13–14/14 plates; 8/14 is below normal and documents a color vision deficiency without the COA speculating on type.

Question 43: The Titmus stereo test (Stereo Fly Test) is used to evaluate a patient's depth perception. This test assesses which of the following visual functions?

Stereopsis (Correct answer)
Color perception
Peripheral vision
Contrast sensitivity

Correct answer: Stereopsis

Stereopsis is the term for three-dimensional vision or depth perception, which is the ability to perceive the world in 3D and judge the distance of objects. The Titmus stereo test, which includes the well-known stereo fly, animal figures, and Wirt circles, uses polarized glasses to present slightly different images to each eye (binocular disparity) to measure a patient's level of stereopsis.

Question 44: What is the primary purpose of the Jackson Cross Cylinder (JCC) during a manual subjective refraction?

To refine the cylinder axis and power (Correct answer)
To determine the initial sphere power
To check for the presence of prism
To measure the pupillary distance

Correct answer: To refine the cylinder axis and power

The Jackson Cross Cylinder (JCC) is a specialized lens used to fine-tune the astigmatism correction. It is flipped and rotated to help the patient determine which of two choices provides clearer vision, allowing the examiner to precisely refine both the axis and the power of the cylinder.

Question 45: Which component of the patient's history includes information about conditions like diabetes, hypertension, and arthritis?

Past Medical History (PMH) (Correct answer)
History of Present Illness (HPI)
Social History
Ocular History

Correct answer: Past Medical History (PMH)

The Past Medical History (PMH) is the section of the history dedicated to documenting the patient's systemic health conditions, such as diabetes and hypertension, which can have significant ocular manifestations.

Question 46: What is an important question to ask a patient that complains of a "red eye"?

Do you have blurred vision? (Correct answer)
Do you wear contact lenses?
Have you experienced eye pain?
Are you allergic to any medications?

Correct answer: Do you have blurred vision?

Explanation: When a patient complains of a "red eye," it's essential to ask about associated symptoms like blurred vision, as it could indicate more serious underlying conditions such as corneal inflammation, uveitis, or glaucoma.

Question 47: Visual information travels from the retina via the optic nerve to which structure first?

Superior colliculus only
Primary visual cortex directly
Lateral geniculate nucleus of the thalamus (Correct answer)
Cerebellum

Correct answer: Lateral geniculate nucleus of the thalamus

Retinal ganglion cell axons project through the optic nerve to synapse in the lateral geniculate nucleus of the thalamus.

Question 48: A patient's left eye turns inward toward their nose when the right eye is covered. What is the term for this misalignment?

Exotropia
Esotropia (Correct answer)
Hypotropia
Hypertropia

Correct answer: Esotropia

Esotropia is the term for an inward turning of the eye. Exotropia is an outward turning, while hypertropia and hypotropia refer to vertical misalignments (upward and downward, respectively).

Question 49: When documenting the Chief Complaint (CC), the ophthalmic assistant should:

List all symptoms the patient mentions during the intake process.
Record the patient's primary reason for the visit in their own words. (Correct answer)
Interpret the patient's symptoms and record a presumptive diagnosis.
Use standardized medical abbreviations to save space in the chart.

Correct answer: Record the patient's primary reason for the visit in their own words.

The chief complaint is the primary reason for the patient's visit and should be documented verbatim, using the patient's own words, to accurately reflect their main concern. Interpreting symptoms, using excessive abbreviations, or listing all symptoms belongs in other parts of the history, like the History of Present Illness (HPI).

Question 50: A patient's intraocular pressure is measured as 25 mmHg with applanation tonometry. However, a pachymetry reading reveals a central corneal thickness of 610 microns. How does this corneal thickness likely affect the IOP measurement?

It only affects non-contact tonometry, not applanation.
It has no significant effect on the IOP reading.
It may cause an artificially low IOP reading.
It may cause an artificially high IOP reading. (Correct answer)

Correct answer: It may cause an artificially high IOP reading.

Goldmann applanation tonometry is calibrated for an average central corneal thickness (CCT) of around 520-545 microns. A thicker cornea is more rigid and requires more force to flatten, which can result in an artificially high intraocular pressure reading. Conversely, a thinner cornea can lead to an artificially low reading.

Question 51: Non-contact tonometry (NCT or 'air puff') measures IOP by analyzing what?

The time or force required for an air pulse to applanate the cornea (Correct answer)
The light reflected from the fluorescein mires
The change in pupil diameter after air contact
The depth of the anterior chamber under pneumatic pressure

Correct answer: The time or force required for an air pulse to applanate the cornea

The NCT instrument delivers a rapid air puff that deforms the cornea. An infrared detection system measures either the time required to flatten a standard corneal area or the force of the puff at the moment of applanation, which correlates with IOP.

Question 52: A patient denies taking any medications but mentions using 'natural eye drops for dryness' purchased at a health food store. How should the COA document this?

Ignore it since it is not a prescription medication
Document it under 'Current Medications' as an OTC/supplement product (Correct answer)
List it under 'Social History' as a lifestyle choice
Record it only if the patient knows the exact brand name

Correct answer: Document it under 'Current Medications' as an OTC/supplement product

Over-the-counter products, herbal supplements, and vitamins can interact with prescribed medications and affect clinical findings. All products currently used — prescription, OTC, or supplement — should be documented in the medications section.

Question 53: Corneal curvature measurement is vital to ensure that contact lens _______.

rests on the tear film
touches the conjunctival surface
touches the corneal surface
rests on the cornea (Correct answer)

Correct answer: rests on the cornea

Explanation: Corneal curvature measurement is vital to ensure that contact lenses fit properly and comfortably. Contact lenses should rest on the cornea, the clear front surface of the eye, for optimal vision correction and comfort. Resting on the cornea ensures proper alignment and avoids discomfort or complications.

Question 54: Compared to indirect ophthalmoscopy, the direct ophthalmoscope provides:

Higher magnification of a small fundus area (Correct answer)
Stereoscopic three-dimensional imaging
Wider field of view
Better view through dense cataracts

Correct answer: Higher magnification of a small fundus area

The direct ophthalmoscope provides approximately 15× magnification but only a small field of the fundus.

Question 55: The crystalline lens is held in position by which structure?

The posterior iris surface
Corneal pressure
Zonular fibers (suspensory ligaments) (Correct answer)
Vitreous humor pressure

Correct answer: Zonular fibers (suspensory ligaments)

Zonular fibers connect the lens equator to the ciliary body, suspending the lens in the optical axis.

Question 56: Which history-taking category would not typically be pertinent when interviewing a patient with a chief complaint of headaches?

Ethnicity (Correct answer)
Cause
Duration
Date

Correct answer: Ethnicity

Explanation: When interviewing a patient with a chief complaint of headaches, ethnicity is typically not pertinent to the assessment of the headache. Instead, aspects such as the duration, cause, and date of onset of the headache are more relevant for diagnosis and treatment planning.

Question 57: If a patient cannot see the largest letter on the Snellen chart (20/400), what is the next step in assessing their visual acuity?

Use the pinhole occluder
Assess their ability to count fingers (CF) at a specified distance (Correct answer)
Move the patient closer to the chart until they can see the largest letter
Record the vision as NLP (No Light Perception)

Correct answer: Assess their ability to count fingers (CF) at a specified distance

When a patient's vision is below the limit of the chart (e.g., less than 20/400), the visual assessment proceeds in a standardized sequence. The next step is to test if they can count the number of fingers the examiner holds up at a certain distance (e.g., CF at 3 feet). If they cannot count fingers, the next steps are to assess for hand motion (HM), and then light perception (LP). NLP is the final designation if the patient cannot perceive a bright light.

Question 58: A-scan ultrasound biometry is primarily performed to measure:

Retinal thickness
Axial length of the eye (Correct answer)
Anterior chamber depth only
Corneal curvature

Correct answer: Axial length of the eye

A-scan ultrasound measures the axial length of the eye, which is essential for intraocular lens power calculation.

Question 59: A patient with a high myopic prescription of -11.00 D has their manifest refraction performed at a standard vertex distance of 14mm. Their new glasses are fit very close to their face, at a vertex distance of 10mm. Which of the following complaints is MOST likely?

The glasses feel too weak.
The patient feels no difference in power.
The patient notices colored fringes around lights.
The glasses feel too strong. (Correct answer)

Correct answer: The glasses feel too strong.

For high minus lenses, moving the lens closer to the eye increases its effective minus power. This change in vertex distance will make the -11.00 D prescription feel stronger to the patient, which can cause symptoms of eyestrain or blurry vision.

Question 60: Which cranial nerve is responsible for innervating the lateral rectus muscle, which abducts the eye?

Cranial Nerve VI (Abducens) (Correct answer)
Cranial Nerve III (Oculomotor)
Cranial Nerve V (Trigeminal)
Cranial Nerve IV (Trochlear)

Correct answer: Cranial Nerve VI (Abducens)

Cranial Nerve VI, the abducens nerve, innervates the lateral rectus muscle. Its function is to abduct the eye (move it outward). Cranial Nerve III (Oculomotor) innervates the majority of the other extraocular muscles, and Cranial Nerve IV (Trochlear) innervates the superior oblique muscle.

Question 61: A patient's best-corrected distance visual acuity is 20/40 in the right eye. When you recheck the vision with a pinhole occluder, it improves to 20/25. What is the most likely cause of the reduced vision?

Amblyopia
Cataract
Macular degeneration
Uncorrected refractive error (Correct answer)

Correct answer: Uncorrected refractive error

The pinhole occluder works by blocking scattered light and allowing only focused central rays to reach the retina. This minimizes the effect of optical imperfections of the eye. An improvement in vision with the pinhole test strongly indicates that the reduced acuity is due to an uncorrected refractive error (like myopia, hyperopia, or astigmatism) that can be corrected with glasses or contact lenses. Vision loss from cataracts, macular disease, or amblyopia typically does not improve with a pinhole.

Question 62: To best isolate and evaluate the action of the right superior rectus muscle, in which of the six cardinal positions of gaze should the patient be directed to look?

Up and to the left
Straight up
Up and to the right (Correct answer)
Down and to the right

Correct answer: Up and to the right

The six cardinal positions of gaze are used to isolate the primary action of specific extraocular muscles. To test the right superior rectus, the eye must first be abducted (turned out). Therefore, having the patient look up and to the right isolates the elevating action of the right superior rectus muscle.

Question 63: Which of the following is the primary purpose of using Ishihara plates during a visual assessment?

To measure intraocular pressure
To screen for red-green color vision deficiencies (Correct answer)
To assess stereopsis and depth perception
To detect central visual field defects

Correct answer: To screen for red-green color vision deficiencies

The Ishihara test consists of a series of pseudoisochromatic plates, which are figures or numbers made of colored dots embedded in a background of differently colored dots. It is specifically designed as a screening tool to detect protanopia and deuteranopia, which are forms of red-green color vision deficiency.

Question 64: A patient calls stating they suddenly see flashes of light and a 'shower of floaters' in one eye. Which of the following is the most appropriate action for the ophthalmic assistant to take?

Instruct the patient to come to the clinic for an emergency evaluation immediately. (Correct answer)
Advise the patient to monitor the symptoms for 24 hours and call back if they worsen.
Schedule the patient for the next available routine appointment.
Document the call and place it in the physician's message box for review at the end of the day.

Correct answer: Instruct the patient to come to the clinic for an emergency evaluation immediately.

The symptoms of sudden flashes and a shower of floaters are classic signs of a potential retinal tear or detachment, which is an ocular emergency requiring immediate evaluation and possible intervention to prevent permanent vision loss. The other options would dangerously delay necessary care.

Question 65: Goldmann applanation tonometry (GAT) measures intraocular pressure by determining the force required to flatten a corneal area of what specific diameter?

3.06 mm (Correct answer)
2.0 mm
6.0 mm
4.5 mm

Correct answer: 3.06 mm

The Goldmann tonometer prism flattens a circular corneal area of 3.06 mm diameter. At this diameter, the forces of surface tension and corneal rigidity cancel each other out, providing an accurate IOP reading.

Question 66: A 5-year-old child is being tested for stereopsis. Which of the following tests would be most appropriate for this age group?

Amsler Grid
Confrontation Fields
Snellen Acuity Chart
Titmus Fly Test (Correct answer)

Correct answer: Titmus Fly Test

The Titmus Fly Test is a common and effective method for evaluating stereopsis (depth perception), especially in children. It uses polarized glasses and features a large, three-dimensional fly, as well as animal figures and graded circles, which are engaging for young patients and do not require them to identify letters or numbers. The Amsler grid tests for central field defects, confrontation fields test peripheral vision, and the Snellen chart measures visual acuity.

Question 67: During the cover-uncover test, the examiner covers the right eye. The left eye moves outward (temporally) to pick up fixation. This finding MOST likely indicates:

Left esotropia (Correct answer)
Orthophoria
Right hypertropia
Left exotropia

Correct answer: Left esotropia

If the uncovered (left) eye moves outward when the right eye is covered, the left eye was turned inward (esotropia) before coverage. The outward refixation movement reveals a manifest inward deviation of the left eye.

Question 68: A patient being treated for glaucoma with topical beta-blocker drops complains of fatigue and shortness of breath. The COA should:

Reassure the patient that these are expected ocular side effects
Encourage the patient to increase the drop frequency to improve IOP control
Document the symptoms and inform the physician, as systemic absorption may be causing cardiovascular/respiratory side effects (Correct answer)
Advise the patient to switch to a different drop brand without physician consultation

Correct answer: Document the symptoms and inform the physician, as systemic absorption may be causing cardiovascular/respiratory side effects

Topical beta-blockers can be systemically absorbed via the nasolacrimal system and cause cardiorespiratory side effects including bradycardia, bronchospasm, and fatigue — particularly dangerous in patients with asthma, COPD, or cardiac conduction disorders.

Question 69: Which fluorescein staining pattern is commonly associated with a poorly fitting rigid gas-permeable lens causing 3 and 9 o'clock staining?

Allergic reaction to lens care solution preservatives
Bacterial keratitis from contaminated lens storage
Desiccation of the corneal epithelium at the 3 and 9 o'clock limbal positions due to inadequate tear coverage (Correct answer)
Corneal hypoxia causing diffuse superficial punctate keratitis

Correct answer: Desiccation of the corneal epithelium at the 3 and 9 o'clock limbal positions due to inadequate tear coverage

Three and 9 o'clock staining results from desiccation of the cornea at the nasal and temporal limbus, where the RGP lens edge causes inadequate blinking and tear film coverage.

Question 70: Which device is used to calculate intraocular lens power before cataract surgery?

Autorefractor
Slit lamp with pachymeter
Keratometer alone
Optical biometry device (e.g., IOL Master) (Correct answer)

Correct answer: Optical biometry device (e.g., IOL Master)

Optical biometry devices measure axial length and corneal curvature to calculate the appropriate IOL power.

Question 71: When the COA performs tonometry and the reading is unexpectedly high (e.g., 35 mmHg) in one eye, what is the MOST appropriate immediate action?

Administer a pressure-lowering drop without a physician order
Dismiss the reading as instrument error and repeat next visit
Document the finding and immediately inform the supervising physician (Correct answer)
Retest only after 30 minutes of rest

Correct answer: Document the finding and immediately inform the supervising physician

An IOP of 35 mmHg is significantly elevated and requires prompt physician evaluation. The COA's role is to accurately document and alert the supervising physician — not to diagnose or independently treat.

Question 72: The vitreous humor consists primarily of:

Aqueous fluid identical to the anterior chamber
Lipids and plasma proteins
Blood cells and serum
Water with collagen fibrils and hyaluronic acid (Correct answer)

Correct answer: Water with collagen fibrils and hyaluronic acid

The vitreous is approximately 99% water supported by a framework of collagen fibrils and hyaluronic acid.

Question 73: What is the primary clinical reason for performing a stereoacuity test such as the Randot or Titmus Fly test?

To evaluate optic nerve function
To measure intraocular pressure
To assess binocular fusion and depth perception (Correct answer)
To detect color vision deficiencies

Correct answer: To assess binocular fusion and depth perception

Stereoacuity tests measure fine depth perception, which requires binocular fusion and intact sensory and motor alignment. They are used to assess amblyopia treatment outcomes, strabismus, and binocular vision disorders.

Question 74: In Hess screen or Lees screen testing, which muscle is identified as the UNDERACTING muscle when a patient's field plot is smaller on the right side?

The left eye muscles (contralateral overaction)
The superior oblique of the left eye only
Both eyes equally
The right eye muscles (ipsilateral underaction) (Correct answer)

Correct answer: The right eye muscles (ipsilateral underaction)

In Hess/Lees screen testing, the eye with the smaller field plot has the underacting (paretic) muscles. A smaller right-side field indicates right eye muscle underaction (paresis), while the left eye shows secondary overaction (larger field) due to Hering's law.

Question 75: Which of the following is a key principle of applanation tonometry, based on the Imbert-Fick law?

Measuring the force required to flatten a specific area of the cornea (Correct answer)
Measuring the depth of indentation on the sclera
Calculating the rebound speed of a probe from the cornea
Analyzing the corneal shape change in response to a puff of air

Correct answer: Measuring the force required to flatten a specific area of the cornea

The Imbert-Fick principle, on which Goldmann applanation tonometry is based, states that the pressure inside an ideal sphere is equal to the force necessary to flatten its surface divided by the area of flattening (P = F/A). Therefore, the tonometer measures the external force required to flatten a 3.06 mm diameter area of the central cornea to calculate the internal pressure.

Question 76: Which of the following BEST describes the proper test distance for standard Snellen distance visual acuity testing?

14 inches (35 cm)
10 feet (3 meters)
25 feet (7.5 meters)
20 feet (6 meters) (Correct answer)

Correct answer: 20 feet (6 meters)

The standard distance for Snellen visual acuity testing is 20 feet (approximately 6 meters). At this distance, light rays entering the eye are essentially parallel, simulating optical infinity and minimizing accommodation.

Question 77: While performing manual lensometry on a pair of glasses, you first focus the thin, single 'sphere' lines at -1.50 D. You then turn the power wheel further until the thick, triple 'cylinder' lines come into focus at -2.75 D. The axis wheel is set to 090. How would this prescription be written in standard minus-cylinder format?

-1.50 -1.25 x 090 (Correct answer)
-1.50 +1.25 x 090
-2.75 -1.25 x 090
-2.75 +1.25 x 180

Correct answer: -1.50 -1.25 x 090

In minus-cylinder lensometry, the first reading (sphere lines) is the sphere power, which is -1.50 D. The cylinder power is the difference between the second reading and the first reading (-2.75 D - (-1.50 D) = -1.25 D). The axis is the setting on the axis wheel when the cylinder lines are in focus, which is 090. Therefore, the prescription is -1.50 -1.25 x 090.

Question 78: Automated perimetry (e.g., Humphrey Visual Field test) measures threshold sensitivity at numerous test locations. Which program is specifically designed for glaucoma monitoring?

Full Field 120-point screening (FT 120)
Goldmann kinetic perimetry protocol
Confrontation field documentation only
Central 24-2 or 30-2 threshold test (Correct answer)

Correct answer: Central 24-2 or 30-2 threshold test

The Humphrey 24-2 (central 24 degrees, 2-degree grid offset) and 30-2 programs test the central visual field in a pattern that closely matches glaucomatous nerve fiber bundle defect patterns, making them the standard for glaucoma monitoring.

Question 79: Which process is useful for measuring corneal astigmatism?

Keratometry (Correct answer)
Slit lamp examination
Visual acuity testing
Refraction

Correct answer: Keratometry

Explanation: Keratometry is a process used to measure corneal astigmatism by assessing the curvature of the cornea.

Question 80: After introduction to the patient, one of the first items that should be obtained as part of history taking is ______:

Medication allergies
The chief complaint or reason for the patient's visit (Correct answer)
Past ocular surgeries
Family medical history

Correct answer: The chief complaint or reason for the patient's visit

Explanation: The chief complaint or reason for the patient's visit. This is a crucial step in history-taking as it helps prioritize the patient's concerns and guides the examination.

Question 81: What is the recommended patient education regarding hydrogen peroxide contact lens care systems?

Hydrogen peroxide systems can be used with any contact lens type including daily disposables
Lenses can be inserted immediately after placing them in the peroxide solution
Rinsing with tap water is acceptable after the neutralization step
Lenses must complete a full neutralization cycle (minimum 6 hours) before insertion (Correct answer)

Correct answer: Lenses must complete a full neutralization cycle (minimum 6 hours) before insertion

Hydrogen peroxide must be fully neutralized (typically over 6 hours via a catalytic disc or tablet) before lens insertion, as un-neutralized peroxide causes severe ocular burning and damage.

Question 82: What is the PRIMARY purpose of documenting the chief complaint at the start of an ophthalmic encounter?

To document the physician's preliminary diagnosis
To record the patient's insurance information
To establish the reason for the visit in the patient's own words (Correct answer)
To list all prior ocular surgeries

Correct answer: To establish the reason for the visit in the patient's own words

The chief complaint is a brief statement, ideally in the patient's own words, describing the primary reason they sought care. It directs the focus of the entire encounter and is a legal and clinical requirement.

Question 83: A patient's contact lens shows a tight-fitting pattern on fluorescein evaluation with a rigid gas-permeable lens. Which of the following best describes this fit?

Interpalpebral fit with superior bearing
Flat fit with excessive edge lift
Steep fit with central pooling and minimal edge clearance (Correct answer)
Alignment fit with uniform fluorescein pattern

Correct answer: Steep fit with central pooling and minimal edge clearance

A steep (tight) RGP fit shows central pooling of fluorescein under the center of the lens and reduced edge lift, indicating the lens curves more steeply than the cornea.

Question 84: An ophthalmologist asks you to instill a cycloplegic drop for a pediatric refraction. Which of the following drops would be the MOST appropriate choice?

Cyclopentolate 1% (Correct answer)
Proparacaine 0.5%
Phenylephrine 2.5%
Ketorolac 0.5%

Correct answer: Cyclopentolate 1%

Cyclopentolate is a cycloplegic agent, meaning it paralyzes the ciliary muscle to inhibit accommodation, which is crucial for obtaining an accurate refraction in children. Phenylephrine is a mydriatic that dilates the pupil but does not significantly affect accommodation. Proparacaine is a topical anesthetic, and Ketorolac is a non-steroidal anti-inflammatory drug (NSAID).

Question 85: The Review of Systems (ROS) in an ophthalmic history specifically asks about systemic symptoms. Which symptom, if present, would be MOST urgent to report to the physician before completing the eye exam?

Acute onset severe headache with nausea and halos around lights (Correct answer)
Mild seasonal allergies
Dry skin in winter months
Occasional mild floaters for several years

Correct answer: Acute onset severe headache with nausea and halos around lights

Severe acute headache with nausea and halos around lights is the classic symptom triad of acute angle-closure glaucoma, a sight-threatening emergency requiring immediate physician evaluation and intervention.

Question 86: Which of the following symptoms requires prompt attention?

Sudden loss of vision (Correct answer)
Diplopia
Pain in the eye
Halos around lights

Correct answer: Sudden loss of vision

Explanation: Sudden loss of vision is a symptom that requires prompt attention because it can indicate a serious condition that needs immediate medical intervention. While the other symptoms are concerning, sudden vision loss is most urgent.

Question 87: Of the following conditions, which one is least likely to cause transient loss of vision?

Migraine
Carotid artery disease
Papilledema
Thyroid disorder (Correct answer)

Correct answer: Thyroid disorder

Explanation: Thyroid disorders can lead to various ocular manifestations such as proptosis (bulging eyes) and double vision, but they are less likely to cause transient loss of vision compared to conditions like carotid artery disease or migraine, which can directly affect blood flow to the eyes or brain.

Question 88: Which of the following drops works primarily as a mydriatic by stimulating the iris dilator muscle, resulting in pupil dilation without significant cycloplegia?

Atropine
Tropicamide
Homatropine
Phenylephrine (Correct answer)

Correct answer: Phenylephrine

Phenylephrine is a sympathomimetic agent that stimulates the alpha-1 adrenergic receptors of the iris dilator muscle, causing pupil dilation (mydriasis) with little to no effect on the ciliary muscle (cycloplegia). Tropicamide, atropine, and homatropine are anticholinergic agents that block the iris sphincter muscle and the ciliary body, causing both mydriasis and cycloplegia.

Question 89: A patient's chart shows 'PCIOL OD' documented after a prior visit. What does this abbreviation indicate?

Primary congenital intraocular lesion in the right eye
Pupil constriction with intraocular light in the right eye
Peripheral corneal inflammatory opacity in the left eye
Posterior chamber intraocular lens implanted in the right eye (Correct answer)

Correct answer: Posterior chamber intraocular lens implanted in the right eye

PCIOL stands for Posterior Chamber Intraocular Lens — the artificial lens placed behind the iris after cataract extraction. OD means oculus dexter (right eye). This notation indicates prior cataract surgery in the right eye.

Question 90: The term used to refer to symptoms due to uncorrected refractive error is ______ :

Asthenopia (Correct answer)
Presbyopia
Keratitis
Myopia

Correct answer: Asthenopia

Explanation: Asthenopia refers to symptoms like eye strain, headaches, or discomfort due to uncorrected refractive error, particularly focusing difficulties.

Question 91: Which contact lens parameter should be steepened if a patient's RGP lens shows excessive movement and falls inferiorly with each blink?

Base curve should be steepened (smaller radius of curvature) (Correct answer)
Overall diameter should be decreased
Back vertex power should be increased
Center thickness should be reduced

Correct answer: Base curve should be steepened (smaller radius of curvature)

Steepening the base curve (using a smaller radius of curvature number) makes the lens fit more closely to the cornea, reducing excessive movement and preventing inferior decentration.

Question 92: Which of the following MOST qualifies as a chief complaint?

Exophoria
Eye fatigue (Correct answer)
Current medications
Munson's sign

Correct answer: Eye fatigue

Explanation: A chief complaint is the primary symptom or concern that brings a patient to seek medical attention. "Eye fatigue" is a symptom described by the patient, making it a chief complaint. The other options are clinical findings or medical history details.

Question 93: Convergence insufficiency most significantly impairs which daily activity?

Night vision in low light
Color discrimination tasks
Distance driving
Reading and sustained near work (Correct answer)

Correct answer: Reading and sustained near work

Convergence insufficiency causes the eyes to have difficulty maintaining alignment at near, producing symptoms during reading.

Question 94: What does 'Dk/t' represent in contact lens science?

Oxygen transmissibility, calculated as permeability divided by lens thickness (Correct answer)
Diffusion coefficient of the cleaning solution
Lens diameter divided by thickness
Dioptric power adjusted for lens thickness

Correct answer: Oxygen transmissibility, calculated as permeability divided by lens thickness

Dk/t is oxygen transmissibility, which accounts for both the material's oxygen permeability (Dk) and the actual thickness (t) of the lens, providing a measure of how much oxygen reaches the cornea.

Question 95: Which of the following is the CORRECT procedure for occluding the eye NOT being tested during monocular visual acuity testing?

Have the patient cup their palm loosely over the non-tested eye
Instill a drop to blur the non-tested eye temporarily
Have the patient tightly close the non-tested eye
Place an opaque occluder firmly over the non-tested eye (Correct answer)

Correct answer: Place an opaque occluder firmly over the non-tested eye

An opaque occluder placed firmly over the non-tested eye prevents light from entering while avoiding the squinting artifact and pressure artifacts associated with closing the eye or pressing the palm against the globe.

Question 96: While performing an Amsler grid test on a patient with dry age-related macular degeneration (AMD), the patient reports that the straight lines of the grid appear wavy and distorted. This finding is known as:

Diplopia
Scotoma
Micropsia
Metamorphopsia (Correct answer)

Correct answer: Metamorphopsia

Metamorphopsia is the medical term for a visual defect that causes linear objects, such as lines on a grid, to look curvy or rounded. It is a hallmark symptom of macular diseases, including age-related macular degeneration. A scotoma is a blind spot, micropsia is when objects appear smaller than they are, and diplopia is double vision.

Question 97: During a swinging flashlight test, an ophthalmic assistant observes that the patient's right pupil dilates when the light is moved from the left eye to the right eye. Which of the following does this finding indicate?

A left oculomotor nerve palsy
A right efferent pupillary defect
Physiologic anisocoria
A right afferent pupillary defect (APD) (Correct answer)

Correct answer: A right afferent pupillary defect (APD)

The swinging flashlight test is used to detect a relative afferent pupillary defect (RAPD or APD), also known as a Marcus Gunn pupil. This defect indicates a problem with the afferent pathway (optic nerve). When light is swung from the normal eye to the affected eye, the affected pupil receives a weaker signal to constrict and will paradoxically dilate.

Question 98: During confrontation visual field testing, the COA is seated opposite the patient at arm's length. Which technique is being used when the examiner wiggles a finger in each quadrant while the patient fixates on the examiner's nose?

Kinetic perimetry
Finger motion confrontation (Correct answer)
Static perimetry
Finger counting confrontation

Correct answer: Finger motion confrontation

When the examiner wiggles a finger in the peripheral field while the patient fixates on the examiner's face, this is the finger motion (or finger wiggle) confrontation technique — a quick gross screening of the visual field.

Question 99: A patient with a right CN VI (abducens) palsy will show which characteristic finding on ocular motility testing?

Right eye cannot abduct in right gaze (Correct answer)
Right eye shows a downward and outward deviation at rest
Right eye cannot elevate in upgaze
Right eye cannot adduct in left gaze

Correct answer: Right eye cannot abduct in right gaze

CN VI innervates the ipsilateral lateral rectus muscle. A right CN VI palsy causes weakness of right eye abduction (inability to move the right eye laterally/temporally), resulting in esotropia worst in right gaze.

Question 100: Which of the following describes the correct procedure for measuring the 'add' power of a lined bifocal lens using a manual lensometer?

Measure the near segment first, then subtract the distance power.
Place the geometric center of the lens in the lensometer and take one reading.
Measure the sphere power in the distance portion, then move to the near segment and re-focus the sphere lines. The add is the difference. (Correct answer)
Measure the distance power, then turn the glasses around and measure the front of the near segment.

Correct answer: Measure the sphere power in the distance portion, then move to the near segment and re-focus the sphere lines. The add is the difference.

To find the add power, first measure the spherical power through the distance portion of the lens. Then, without changing the axis, move the lens upward to center the near segment in the lensometer. Re-focus the sphere lines (single, thin lines) and note the new power. The add power is the algebraic difference between the near sphere reading and the distance sphere reading, and it is always a positive value.

Question 101: The use of topical steroids may induce which of the following?

Retinal detachment
Cataracts (Correct answer)
Keratoconus
Hyphema

Correct answer: Cataracts

Explanation: The prolonged use of topical steroids can induce the development of cataracts, which are opacities in the lens of the eye. Cataracts can lead to blurry vision and ultimately require surgical removal for vision improvement.

Question 102: Pupil constriction (miosis) and dilation (mydriasis) are controlled by which iris muscles?

Sphincter muscle for miosis and dilator muscle for mydriasis (Correct answer)
Choroidal smooth muscle
Zonular fiber tension
Ciliary muscle for both responses

Correct answer: Sphincter muscle for miosis and dilator muscle for mydriasis

The iris sphincter muscle (parasympathetic) constricts the pupil and the dilator muscle (sympathetic) dilates it.

Question 103: A patient is prescribed a prostaglandin analog for glaucoma. Which of the following is a common, and often permanent, side effect the ophthalmic assistant should mention?

Increased iris pigmentation (Correct answer)
Corneal thinning
Decreased night vision
Frequent headaches

Correct answer: Increased iris pigmentation

Prostaglandin analogs, such as latanoprost, are known to cause several side effects, including increased pigmentation (darkening) of the iris. This change is often permanent. Other common side effects include eyelash growth and conjunctival hyperemia (redness). Corneal thinning, decreased night vision, and frequent headaches are not primary, common side effects of this class of medication.

Question 104: A patient states they use brimonidine drops twice daily. In the medical record, this would be documented under which section?

Current medications (Correct answer)
Chief complaint
Review of systems
Assessment and plan

Correct answer: Current medications

Brimonidine is a topical alpha-2 agonist used to lower intraocular pressure. All topical and systemic medications a patient is currently taking should be listed in the 'Current Medications' section of the medical record.

Question 105: What term is used to describe the rhythmic, involuntary, back-and-forth movement of the eyes?

Duction
Strabismus
Version
Nystagmus (Correct answer)

Correct answer: Nystagmus

Nystagmus is the medical term for rapid, involuntary, and repetitive eye movements. These movements can be side-to-side (horizontal), up-and-down (vertical), or rotary. Duction, version, and strabismus all relate to voluntary eye alignment and movement, not involuntary oscillations.

Question 106: The optic nerve cup-to-disc ratio (CDR) is evaluated during ophthalmic assessment. Which CDR value is MOST suggestive of glaucomatous optic nerve change?

0.8 OD with inferior rim thinning (Correct answer)
0.2 OU
0.3 OD, 0.3 OS
0.5 OU with symmetrical appearance

Correct answer: 0.8 OD with inferior rim thinning

A CDR of 0.8 is large and, combined with inferior rim thinning (loss of the ISNT rule pattern), is highly suspicious for glaucomatous optic neuropathy. Both the ratio and the rim quality must be assessed.

Question 107: Which maneuver is used during the Maddox rod test to quantify the amount of vertical phoria?

Using a fixation star target at 6 meters only
Alternately covering each eye to break fusion
Asking the patient to fixate on a red dot while moving the flashlight
Placing the Maddox rod horizontally over one eye and using vertical prisms to neutralize the perceived line displacement (Correct answer)

Correct answer: Placing the Maddox rod horizontally over one eye and using vertical prisms to neutralize the perceived line displacement

For vertical phoria measurement, the Maddox rod is placed horizontally over one eye, converting the point light into a vertical line. Prism is then added to neutralize the separation between the light and the line — the prism power required equals the phoria.

Question 108: A patient describes their main symptom as 'blurry vision'. To properly document the History of Present Illness (HPI), which of the following is the BEST follow-up question?

"Are you allergic to any medications?"
"Do you have a family history of blurry vision?"
"Have you had eye surgery in the past?"
"Did this start suddenly or gradually?" (Correct answer)

Correct answer: "Did this start suddenly or gradually?"

The History of Present Illness (HPI) should elaborate on the chief complaint. Asking about the onset (sudden vs. gradual) is a key element of the HPI, helping to narrow down potential causes. Family history, allergies, and past surgeries are important but belong in their respective sections of the history, not the HPI.

Question 109: A 75-year-old patient with a dense nuclear sclerotic cataract has a visual acuity of 20/200. The surgeon wants to estimate the potential for visual improvement after cataract surgery. Which test would be most appropriate to perform?

Potential Acuity Meter (PAM) (Correct answer)
Color Vision Test
Contrast Sensitivity Test
Amsler Grid

Correct answer: Potential Acuity Meter (PAM)

The Potential Acuity Meter (PAM) is specifically designed to estimate the retinal visual acuity in eyes with media opacities, such as cataracts. It projects a miniature Snellen chart through a clear window in the opacity directly onto the retina, bypassing the cataract to assess the macula's functional capability. This helps set realistic expectations for postoperative vision.

Question 110: A patient is asked to read the 20/20 line but misses two letters. How is this properly documented in Snellen notation?

20/25 +2
CF at 20 feet
20/20 (partial)
20/20 -2 (Correct answer)

Correct answer: 20/20 -2

When a patient reads most but not all letters on a line, the acuity is recorded as the line size with a minus for each letter missed (e.g., 20/20 -2 means 3 of 5 letters read correctly on the 20/20 line).

Question 111: Which test uses a prism to center the corneal reflex?

Hess
Hirschberg
Krimsky (Correct answer)
Worth four dot

Correct answer: Krimsky

Explanation: The Krimsky test uses a prism to center the corneal reflex when assessing ocular alignment. By observing the position of the corneal light reflex relative to the center of the pupil, the examiner can determine the presence and magnitude of strabismus or misalignment of the eyes.

Question 112: Which visual acuity chart uses pictures such as a house, apple, and umbrella instead of letters, and is most appropriate for which patient population?

Snellen chart — for adults with low literacy
ETDRS chart — for clinical trials involving children
Bailey-Lovie chart — for patients with low vision
Allen chart — for preschool children aged 2.5 to 5 years (Correct answer)

Correct answer: Allen chart — for preschool children aged 2.5 to 5 years

The Allen chart uses common pictures (birthday cake, horse, hand, car, etc.) that pre-school children recognize. It is used for children approximately 2.5 to 5 years old who cannot yet identify letters.

Question 113: Which type of glaucoma is characterized by a narrow or closed iridocorneal angle that obstructs aqueous outflow?

Angle-closure glaucoma (ACG) (Correct answer)
Congenital glaucoma
Normal tension glaucoma (NTG)
Primary open-angle glaucoma (POAG)

Correct answer: Angle-closure glaucoma (ACG)

Angle-closure glaucoma results from apposition or adhesion of the peripheral iris against the trabecular meshwork, blocking aqueous humor outflow through the iridocorneal angle and causing IOP elevation.

Question 114: When teaching a patient to insert a soft contact lens, which instruction is most important for preventing infection?

Clean the lens only once per week to preserve the disinfecting solution
Wear lenses for extended periods to reduce handling frequency
Wash and dry hands thoroughly before handling lenses (Correct answer)
Always insert the lens straight from the storage case without rinsing

Correct answer: Wash and dry hands thoroughly before handling lenses

Hand hygiene is the single most important step in preventing contact lens-related infections, as contaminated hands are the primary route of pathogen transfer to the ocular surface.

Question 115: What is the function of a pupillometer in ophthalmic practice?

Measure intraocular pressure
Test color vision
Examine the optic disc
Measure the interpupillary distance (Correct answer)

Correct answer: Measure the interpupillary distance

A pupillometer measures the pupillary distance (PD) to ensure optical centers of lenses align with visual axes.

Question 116: A patient presents with a sudden onset of severe eye pain, nausea, blurred vision, and halos around lights. Tonometry reveals a very high IOP. Which type of glaucoma is most likely responsible for these symptoms?

Traumatic glaucoma
Normal-tension glaucoma
Primary open-angle glaucoma
Acute angle-closure glaucoma (Correct answer)

Correct answer: Acute angle-closure glaucoma

Acute angle-closure glaucoma is a medical emergency characterized by a sudden blockage of the eye's drainage angle, leading to a rapid and severe spike in intraocular pressure. This causes symptoms like intense eye pain, redness, blurred vision, halos, headache, and nausea. Primary open-angle glaucoma, the most common form, is typically painless and develops slowly.

Question 117: When neutralizing a lens in the lensometer, the target mires are perfectly clear and centered when the power wheel is at +3.00 D. However, to center the target in the reticle, the entire lens holder had to be moved down, causing the target to be displaced 2 units up on the prism scale. How should this prism be recorded?

2Δ Base Out
2Δ Base Down
2Δ Base In
2Δ Base Up (Correct answer)

Correct answer: 2Δ Base Up

Prism shifts the image toward its apex. To re-center the image, the lens must be moved in the direction of the prism's base. Since the lens holder was moved down to center the target, the image was originally displaced upward (towards the apex). This indicates the presence of Base Up prism. The rings on the reticle indicate the amount of prism in diopters.

Question 118: The physiologic blind spot corresponds to which ocular structure?

The ora serrata
The macula lutea
The optic disc where no photoreceptors exist (Correct answer)
The fovea centralis

Correct answer: The optic disc where no photoreceptors exist

The optic disc contains no photoreceptors because retinal nerve fibers exit here, creating a scotoma about 15 degrees temporal to fixation.

Question 119: In ocular motility testing using the H pattern (nine cardinal positions of gaze), which muscle is being evaluated when the patient looks to the right and UP?

Right lateral rectus (LR) and left medial rectus (MR)
Right inferior oblique (IO) and left superior rectus (SR)
Right superior oblique (SO) and left inferior rectus (IR)
Right superior rectus (SR) and left inferior oblique (IO) (Correct answer)

Correct answer: Right superior rectus (SR) and left inferior oblique (IO)

In right and up gaze, the right superior rectus is the primary elevator and the left inferior oblique is the primary elevator of the fellow eye in that conjugate gaze position. The superior rectus and inferior oblique are yoke muscles (Hering's law) for upgaze.

Question 120: When evaluating a patient's eye movements in the cardinal positions of gaze, which pair of muscles works together (as yoke muscles) to move the eyes down and to the left?

Left Superior Oblique and Right Inferior Rectus
Left Superior Rectus and Right Inferior Oblique
Left Lateral Rectus and Right Medial Rectus
Left Inferior Rectus and Right Superior Oblique (Correct answer)

Correct answer: Left Inferior Rectus and Right Superior Oblique

Yoke muscles are pairs of muscles in opposite eyes that work together to produce conjugate eye movements. To look down and to the left, the left eye's primary depressor in that position (left inferior rectus) and the right eye's primary depressor in that position (right superior oblique) must contract simultaneously.

Question 121: The Ishihara color vision test primarily screens for deficiencies in which color axis?

Red-green defects (protan and deutan) (Correct answer)
Blue-yellow (tritan) defects
Achromatic (complete color blindness)
UV light sensitivity

Correct answer: Red-green defects (protan and deutan)

The Ishihara pseudoisochromatic plates are specifically designed to detect red-green color deficiencies (protanopia, protanomaly, deuteranopia, deuteranomaly), which are the most common inherited color vision defects.

Question 122: When performing manual keratometry, the ophthalmic assistant is unable to get clear, stable mire images, and they appear to be pulsating or jumping. This finding is most indicative of which of the following?

High intraocular pressure.
Incorrect eyepiece focus.
A poor tear film or dry eye. (Correct answer)
A dense nuclear sclerotic cataract.

Correct answer: A poor tear film or dry eye.

Unstable, distorted, or pulsating mires during keratometry are often a sign of an inadequate tear film or significant dry eye, as the mires are reflected off the tear layer covering the cornea. Asking the patient to blink can often temporarily resolve this issue and allow for a more accurate measurement.

Question 123: The normal tear film is composed of how many distinct layers?

Five layers including a fibrin layer
Two layers only
One homogeneous layer
Three layers: lipid, aqueous, and mucin (Correct answer)

Correct answer: Three layers: lipid, aqueous, and mucin

The tear film has three layers: outer lipid (from meibomian glands), middle aqueous (from lacrimal gland), and inner mucin (from goblet cells).

Question 124: A patient is being evaluated for double vision. During motility testing, the patient is unable to abduct their left eye (turn it outward). This limitation is most likely due to a weakness of which muscle and a palsy of which cranial nerve?

Inferior Oblique, CN III
Superior Oblique, CN IV
Lateral Rectus, CN VI (Correct answer)
Medial Rectus, CN III

Correct answer: Lateral Rectus, CN VI

Abduction, or moving the eye outward away from the nose, is the primary action of the lateral rectus muscle. The lateral rectus muscle is solely innervated by the sixth cranial nerve (CN VI), also known as the abducens nerve.

Question 125: Which of the following scenarios would MOST likely lead to an inaccurate intraocular pressure reading when using a non-contact tonometer (NCT)?

The patient has a large pupil.
The patient has mild nuclear sclerosis.
The patient is squeezing their eyelids tightly. (Correct answer)
The patient recently used lubricating eye drops.

Correct answer: The patient is squeezing their eyelids tightly.

Squeezing the eyelids (the Valsalva maneuver) increases external pressure on the globe, which can artificially elevate the intraocular pressure reading. This is a common source of error in all forms of tonometry, including non-contact tonometry. The other factors listed are less likely to have a significant impact on an NCT reading.

Question 126: Which part of the patient examination is performed by asking specific questions in an orderly sequence?

Visual field testing
History (Correct answer)
Tonometry
Refraction

Correct answer: History

Explanation: Patient history is obtained by asking specific questions in an orderly sequence to gather information about the patient's symptoms, medical history, and any relevant factors that may impact their eye health. This step is crucial in understanding the patient's condition and guiding further examination and treatment. Refraction, tonometry, and visual field testing are important components of the eye examination, but they do not involve asking specific questions to gather patient history.

Question 127: During a cover-uncover test, the examiner notes that the uncovered eye moves outward to pick up fixation when the other eye is covered. This movement is only observed during the test. This finding is indicative of a(n):

Esophoria (Correct answer)
Exophoria
Exotropia
Esotropia

Correct answer: Esophoria

A phoria is a latent deviation that is only present when binocular vision is interrupted, such as by covering an eye. Since the eye was turned inward (eso-) under the cover and moves outward to fixate when uncovered, this indicates an esophoria. A tropia is a manifest deviation that is always present.

Question 128: Specular microscopy is used to evaluate which ocular structure?

Retinal nerve fiber layer
Crystalline lens density
Trabecular meshwork
Corneal endothelium (Correct answer)

Correct answer: Corneal endothelium

Specular microscopy images corneal endothelial cells to assess their density, size, and morphology.

Question 129: Which contact lens design uses alternating concentric zones to provide correction for both near and distance vision?

Aspheric multifocal
Concentric/annular multifocal (Correct answer)
Translating bifocal
Monovision

Correct answer: Concentric/annular multifocal

Concentric (annular) multifocal contact lenses have alternating rings of distance and near power arranged in concentric zones, allowing simultaneous vision correction.

Question 130: During a soft contact lens over-refraction, what is the primary purpose of this procedure?

To assess corneal curvature changes from lens wear
To determine the final contact lens power needed by refracting over a trial lens (Correct answer)
To evaluate the tear film stability under the lens
To measure the fit of the trial lens on the cornea

Correct answer: To determine the final contact lens power needed by refracting over a trial lens

Over-refraction determines the residual refractive error remaining while the patient wears a trial contact lens, allowing the practitioner to calculate the correct final lens power.

Question 131: In the common pupillary examination acronym PERRLA, what does the 'A' represent?

Anisocoria
Adduction
Afferent
Accommodation (Correct answer)

Correct answer: Accommodation

PERRLA stands for Pupils Equal, Round, Reactive to Light and Accommodation. The 'A' refers to accommodation, which is the process by which the eye changes optical power to maintain a clear image or focus on an object as its distance varies. This is tested by having the patient shift focus from a distant object to a near object, which should cause pupillary constriction.

Question 132: Which instrument provides a wide-field inverted view of the fundus?

Binocular indirect ophthalmoscope (Correct answer)
Autorefractor
Direct ophthalmoscope
Slit lamp alone

Correct answer: Binocular indirect ophthalmoscope

The binocular indirect ophthalmoscope provides a wide-field stereoscopic view of the fundus using a condensing lens.

Question 133: The acronym 'F-D-S-L' (Frequency, Duration, Severity, Location) is often used to gather more details about the patient's:

Past Medical History
Social History
Medication Allergies
History of Present Illness (HPI) (Correct answer)

Correct answer: History of Present Illness (HPI)

The History of Present Illness (HPI) is an expansion of the chief complaint. Mnemonics like OLDCARTS or F-D-S-L are used to ensure a thorough characterization of the primary symptom(s), including its frequency, duration, severity, location, and other associated factors.

Question 134: Which condition is most directly associated with chronic corneal hypoxia from extended contact lens wear?

Fuchs endothelial dystrophy
Pinguecula
Pterygium formation
Corneal neovascularization (pannus) (Correct answer)

Correct answer: Corneal neovascularization (pannus)

Corneal neovascularization occurs when the oxygen-deprived cornea stimulates new blood vessel ingrowth from the limbus to compensate for hypoxia caused by inadequate oxygen transmission through extended contact lens wear.

Question 135: Which test best evaluates for a latent deviation (phoria) that is only revealed when binocular fusion is disrupted?

Alternate cover test (Correct answer)
Maddox rod test only
Cover-uncover test
Hirschberg corneal reflex test

Correct answer: Alternate cover test

The alternate cover test rapidly moves the occluder from eye to eye, preventing fusion and revealing both manifest (tropia) and latent (phoria) deviations. The cover-uncover test reveals only manifest deviations.

Question 136: The primary purpose of using lissamine green dye during an ocular surface evaluation is to stain what?

The tear film to measure breakup time
Areas of epithelial defects on the cornea
The endothelial cell layer of the cornea
Dead and devitalized cells on the conjunctiva and cornea (Correct answer)

Correct answer: Dead and devitalized cells on the conjunctiva and cornea

Lissamine green is a vital dye that selectively stains dead or devitalized cells and mucus on the ocular surface, particularly the conjunctiva. It is especially useful for evaluating dry eye disease and other ocular surface disorders. Fluorescein sodium is used to highlight corneal epithelial defects and measure tear breakup time.

Question 137: While performing keratometry, the ophthalmic assistant obtains two different readings: 44.50 D at 180 degrees and 42.00 D at 90 degrees. This difference is used to quantify which of the following?

Axial length
Intraocular pressure
Corneal diameter
Corneal astigmatism (Correct answer)

Correct answer: Corneal astigmatism

Keratometry measures the curvature of the cornea in its two principal meridians. A difference between these two measurements (K-readings) indicates that the cornea is not perfectly spherical. This difference is the amount of corneal astigmatism.

Question 138: A patient's uncorrected visual acuity is 20/40. When you have them view the chart through a pinhole occluder, their vision improves to 20/25. What is the MOST likely cause of the patient's reduced vision?

Macular degeneration
A dense cataract
Amblyopia
Uncorrected refractive error (Correct answer)

Correct answer: Uncorrected refractive error

The pinhole occluder works by blocking peripheral light rays and allowing only central rays to pass through to the retina, which minimizes the effect of optical imperfections in the cornea and lens. A significant improvement in acuity with the pinhole test strongly indicates that the reduced vision is due to an uncorrected refractive error (like myopia, hyperopia, or astigmatism) that can be corrected with glasses. Vision would likely worsen with macular disease or a central cataract and would not improve in the case of amblyopia.

Question 139: A 5-year-old child presents for an eye exam. The ophthalmic assistant observes that the child's right eye is deviated upwards compared to the left eye. This condition is best described as a:

Left Hypotropia
Left Esotropia
Right Exotropia
Right Hypertropia (Correct answer)

Correct answer: Right Hypertropia

Hypertropia refers to a vertical misalignment where one eye is deviated upward relative to the other. Since the right eye is higher, it is termed a right hypertropia. Alternatively, this could be described as a left hypotropia (the left eye being lower), but Right Hypertropia is the more direct description based on the observation.

Question 140: Which layer of the cornea has the greatest capacity for regeneration after injury?

Stroma
Epithelium (Correct answer)
Descemet's membrane
Bowman's layer

Correct answer: Epithelium

The corneal epithelium regenerates completely within 24–72 hours because of its rapid mitotic activity.

Question 141: When administering the Ishihara color vision test, which of the following is a critical procedural step for ensuring accuracy?

Allowing the patient to trace the numbers with their finger
Testing each eye individually at a specific reading distance (Correct answer)
Performing the test in a dimly lit room to enhance colors
Giving the patient unlimited time to view each plate

Correct answer: Testing each eye individually at a specific reading distance

Proper procedure for the Ishihara test requires testing each eye separately. The test should be conducted in adequate, daylight-like illumination, at a distance of about 75 cm, and the patient should identify the number within about three seconds per plate without coaching or tracing. These standardized conditions are necessary for a valid assessment of congenital red-green color vision defects.

Question 142: The Worth 4-Dot test uses a flashlight with four illuminated circles (one red on top, two green on the sides, one white on the bottom). The patient wears red-green glasses. If the patient reports seeing four dots, what does this indicate?

Normal binocular fusion (Correct answer)
Suppression of the right eye
Diplopia
Suppression of the left eye

Correct answer: Normal binocular fusion

Seeing all four dots (one red, two green, one white/mixed) indicates both eyes are contributing to the visual percept and the patient has binocular fusion at the tested distance.

Question 143: A patient's IOP is measured by GAT as 14 mmHg OD and 15 mmHg OS. The COA notes the corneal pachymetry is 490 microns OU. How should the COA interpret this?

Pachymetry has no relationship to IOP measurement accuracy
IOP is normal; thin corneas do not affect GAT readings
IOP may be falsely high; thin corneas overestimate true IOP with GAT
IOP may be falsely low; thin corneas tend to underestimate true IOP with GAT (Correct answer)

Correct answer: IOP may be falsely low; thin corneas tend to underestimate true IOP with GAT

GAT assumes a standard central corneal thickness (CCT) of ~550 microns. Corneas thinner than 550 microns are more easily applanated, requiring less force, causing GAT to underestimate true IOP. A CCT of 490 microns is significantly thin.

Question 144: A patient with high, against-the-rule astigmatism requires an intraocular pressure check using Goldmann applanation tonometry. To obtain an accurate measurement, how should the ophthalmic assistant orient the tonometer prism?

The orientation of the prism does not affect the reading.
Rotate the prism to the axis of the plus cylinder.
Center the prism with the 0-degree mark aligned horizontally.
Align the prism so the red line is on the axis of the minus cylinder. (Correct answer)

Correct answer: Align the prism so the red line is on the axis of the minus cylinder.

For patients with corneal astigmatism greater than 3.00 diopters, the flattened area of the cornea becomes elliptical, which can lead to an inaccurate IOP reading. To compensate, the Goldmann tonometer prism should be rotated so that the red line on the prism is aligned with the patient's minus cylinder axis.

Question 145: Which notation correctly documents a patient's visual acuity when they cannot read the largest letter on the Snellen chart even with their best spectacle correction?

20/400
CF (counting fingers) (Correct answer)
LP (light perception)
HM (hand motion)

Correct answer: CF (counting fingers)

When a patient cannot resolve the 20/400 optotype, testing progresses to counting fingers (CF) at a specified distance, then hand motion (HM), light perception (LP), and finally no light perception (NLP). The correct next documentation step is CF.

Question 146: Which of the following tests is designed to measure a patient's ability to distinguish between different shades of gray and is particularly useful for assessing real-world visual function in low light or glare conditions?

Potential Acuity Meter (PAM)
Pelli-Robson Chart (Correct answer)
Titmus Stereo Test
Ishihara Test

Correct answer: Pelli-Robson Chart

The Pelli-Robson chart is a common method for testing contrast sensitivity, which is the ability to discern objects from their background. This test uses letters of a fixed size that become progressively fainter (lower contrast) down the chart. This differs from standard acuity charts that use high-contrast black letters. Low contrast sensitivity can explain visual complaints in patients with good acuity, especially in situations like night driving.

Question 147: OCT (Optical Coherence Tomography) in glaucoma management primarily measures:

Intraocular pressure fluctuation
Anterior chamber angle
Visual acuity threshold
Retinal nerve fiber layer thickness (Correct answer)

Correct answer: Retinal nerve fiber layer thickness

OCT measures retinal nerve fiber layer thickness, enabling detection and monitoring of glaucomatous structural damage.

Question 148: A 68-year-old patient presents for a follow-up visit for glaucoma. As part of the history taking, which of the following questions is most critical to ask regarding their medication?

"Do you like the color of the bottle cap?"
"Have you been using your eye drops as prescribed and when was your last dose?" (Correct answer)
"Are you still using the same pharmacy?"
"Did you bring your eye drop bottles with you today?"

Correct answer: "Have you been using your eye drops as prescribed and when was your last dose?"

For chronic conditions like glaucoma, assessing medication adherence and timing of the last dose is crucial because it directly impacts the measurement of intraocular pressure (IOP) during the visit. An inaccurately low or high IOP reading could result if the patient has not been using their drops correctly.

Question 149: What is the term for the measurement of the contact lens that describes its total width from edge to edge?

Base curve
Back vertex power
Overall diameter (OAD) (Correct answer)
Optical zone diameter

Correct answer: Overall diameter (OAD)

The overall diameter (OAD) refers to the total width of the contact lens measured from one edge to the other, and it is a key parameter in contact lens fitting.

Question 150: What is the generally accepted range for normal intraocular pressure (IOP) in the adult population?

22-30 mmHg
3-7 mmHg
10-21 mmHg (Correct answer)
5-10 mmHg

Correct answer: 10-21 mmHg

The statistically normal range for intraocular pressure in adults is typically between 10 and 21 millimeters of mercury (mmHg). Pressures consistently above 21 mmHg are considered ocular hypertension and increase the risk for developing glaucoma, although glaucoma can also develop at pressures within the normal range (normal-tension glaucoma).

Question 151: Which of the following is considered the 'gold standard' for measuring intraocular pressure?

Non-contact tonometry (NCT)
Goldmann applanation tonometry (Correct answer)
Schiotz tonometry
Digital palpation

Correct answer: Goldmann applanation tonometry

Goldmann applanation tonometry (GAT) is widely considered the international gold standard for measuring intraocular pressure due to its accuracy and reproducibility. It works by measuring the force required to flatten a specific area of the cornea.

Question 152: Which of the following conditions is NOT hereditary?

Conjunctivitis (Correct answer)
Diabetes
Nystagmus
Migraines

Correct answer: Conjunctivitis

Explanation: Conjunctivitis, also known as pink eye, is typically caused by infections (viral or bacterial) or allergies and is not inherited. The other conditions listed (migraines, diabetes, and nystagmus) have hereditary components.

Question 153: Accommodation refers to which physiologic process?

Adjustment of color perception in dim light
Regulation of aqueous humor production
Adjustment of pupil size to light
Changing lens curvature to focus at different distances (Correct answer)

Correct answer: Changing lens curvature to focus at different distances

Accommodation changes the curvature of the crystalline lens by ciliary muscle contraction to focus objects at near.

Question 154: Which photoreceptor cells are responsible for night (scotopic) vision?

Cones
Ganglion cells
Müller cells
Rods (Correct answer)

Correct answer: Rods

Rod photoreceptors are extremely sensitive to light and mediate vision under low-light (scotopic) conditions.

Question 155: The Hirschberg test estimates the angle of strabismus by observing corneal light reflections. If the corneal reflex appears at the pupil margin of the right eye and centered in the left eye, approximately how many prism diopters of deviation is estimated?

15–20 prism diopters (Correct answer)
30–45 prism diopters
60–80 prism diopters
5–10 prism diopters

Correct answer: 15–20 prism diopters

In the Hirschberg test, a decentered corneal light reflex at the pupil margin corresponds to approximately 15 prism diopters (pd) of deviation. Each millimeter of decentration equals approximately 15 pd (some sources use 7° or 22 pd/mm depending on reference).

Question 156: During the swinging flashlight test (RAPD test), the examiner swings a light between the two eyes every 2–3 seconds and observes the pupillary responses. A relative afferent pupillary defect (RAPD) in the right eye is indicated by:

Both pupils dilate when the light moves from the left eye to the right eye (Correct answer)
Both pupils dilate when the light moves from the right eye to the left eye
Both pupils constrict when the light moves to the right eye
The right pupil does not react to direct stimulation but constricts to consensual stimulation

Correct answer: Both pupils dilate when the light moves from the left eye to the right eye

A RAPD in the right eye means the right optic nerve transmits less light signal. When light swings to the right eye, both pupils receive a weaker 'bright light' signal and dilate — the right pupil appears to dilate when directly illuminated, which is the pathological finding.

Question 157: A patient is being treated for postoperative inflammation following cataract surgery. The surgeon has prescribed both prednisolone acetate and ketorolac. What is the primary functional difference between these two drops?

Prednisolone is an antibiotic, while ketorolac is an anti-inflammatory.
Prednisolone treats pain, while ketorolac treats inflammation.
Both are steroids, but prednisolone is stronger.
Prednisolone is a steroid, while ketorolac is a non-steroidal anti-inflammatory drug (NSAID). (Correct answer)

Correct answer: Prednisolone is a steroid, while ketorolac is a non-steroidal anti-inflammatory drug (NSAID).

Prednisolone acetate is a potent corticosteroid, while ketorolac is a non-steroidal anti-inflammatory drug (NSAID). Both are used to control inflammation, but they work through different mechanisms. Steroids broadly suppress the inflammatory cascade, while NSAIDs primarily inhibit prostaglandin synthesis. Using them together can provide a more comprehensive anti-inflammatory effect.

Question 158: What is the purpose of the sagittal depth (sag) in contact lens fitting?

It describes the vault of the lens over the cornea, determining how the lens sits relative to the corneal surface (Correct answer)
It measures the thickness at the lens center to calculate Dk/t
It indicates the dioptric power needed to correct the patient's refractive error
It measures the oxygen transmissibility of the lens material

Correct answer: It describes the vault of the lens over the cornea, determining how the lens sits relative to the corneal surface

Sagittal depth (sag) is the depth of the contact lens vault — the perpendicular distance from the chord diameter to the back surface — which determines how the lens fits relative to the corneal height.

Question 159: What is the purpose of the Brückner test (red reflex comparison) in pediatric eye exams?

To measure the cup-to-disc ratio in young children
To test near convergence amplitude
To screen for asymmetric red reflexes that may indicate strabismus, amblyopia, or media opacities (Correct answer)
To quantify the refractive error of each eye

Correct answer: To screen for asymmetric red reflexes that may indicate strabismus, amblyopia, or media opacities

The Brückner test uses a direct ophthalmoscope at ~1 meter to compare the red reflexes of both eyes simultaneously. Asymmetry in brightness or color can indicate strabismus, anisometropia, amblyopia risk, or media opacities (cataract, corneal scar).

Question 160: What does the abbreviation 'BCVA' stand for in an ophthalmic record?

Bilateral central visual acuity
Best corrected visual acuity (Correct answer)
Binocular corneal visual angle
Baseline corneal visual assessment

Correct answer: Best corrected visual acuity

BCVA stands for Best Corrected Visual Acuity — the sharpest vision a patient can achieve with optimal spectacle or contact lens correction. It is the standard metric for assessing visual function.

Question 161: When documenting allergies in an ophthalmic history, which information is MOST important to include beyond the allergen name?

The specific reaction experienced (e.g., rash, anaphylaxis, GI upset) (Correct answer)
The patient's insurance formulary
The date the patient first noticed the allergy
The pharmacy where the allergy was first treated

Correct answer: The specific reaction experienced (e.g., rash, anaphylaxis, GI upset)

Knowing the type of reaction helps distinguish true allergies (immune-mediated, potentially life-threatening) from intolerances or side effects. This guides the physician in prescribing alternative medications safely.

Question 162: A lensometer (lensmeter) is used to measure which of the following?

Corneal curvature
Prescription power of spectacle lenses (Correct answer)
Intraocular pressure
Pupil diameter

Correct answer: Prescription power of spectacle lenses

A lensometer measures the sphere, cylinder, axis, and prism of an existing spectacle lens.

Question 163: What is the primary function of the Goldmann applanation tonometer?

Measure corneal curvature
Evaluate the optic nerve
Measure crystalline lens thickness
Measure intraocular pressure (Correct answer)

Correct answer: Measure intraocular pressure

The Goldmann applanation tonometer is considered the gold standard for measuring intraocular pressure.

Question 164: A patient switches from glasses (spectacle Rx: -5.00 D) to contact lenses. Due to vertex distance, the expected contact lens power will be approximately:

Exactly the same as the spectacle prescription
More minus than the spectacle prescription
Less minus than the spectacle prescription (Correct answer)
More plus than the spectacle prescription

Correct answer: Less minus than the spectacle prescription

As myopic spectacle lenses are moved closer to the eye (from ~12 mm vertex to 0 mm at the cornea), the effective power decreases, so the contact lens needs less minus power than the spectacle prescription.

Question 165: When performing keratometry, what information is obtained?

Intraocular pressure in two meridians
Anterior chamber depth
Corneal thickness at the apex
Anterior corneal curvature in the principal meridians (Correct answer)

Correct answer: Anterior corneal curvature in the principal meridians

Keratometry measures the radius of curvature of the anterior cornea in the flattest and steepest meridians.

Question 166: What is the recommended first step before performing Goldmann applanation tonometry?

Dilate the pupil with tropicamide
Ask the patient to remove contact lenses only if soft lenses are worn
Check that the slit lamp is set to white light
Instill a topical anesthetic and fluorescein (Correct answer)

Correct answer: Instill a topical anesthetic and fluorescein

GAT requires topical anesthesia for patient comfort and fluorescein sodium to create the characteristic tear film meniscus rings that enable proper mire alignment. Both are instilled before the procedure.

Question 167: A patient's intraocular pressure (IOP) measures 28 mmHg via Goldmann applanation tonometry. Pachymetry reveals a central corneal thickness of 610 µm. How does the corneal thickness likely affect this IOP reading?

The IOP reading is artificially lowered by the thick cornea.
The true IOP is likely lower than 28 mmHg. (Correct answer)
Corneal thickness does not affect Goldmann tonometry readings.
The true IOP is likely higher than 28 mmHg.

Correct answer: The true IOP is likely lower than 28 mmHg.

Goldmann tonometry is calibrated for an average central corneal thickness of about 520-540 µm. A thicker-than-average cornea provides more resistance to the tonometer probe, resulting in a falsely high IOP reading. Conversely, a thinner cornea would lead to a falsely low reading.

Question 168: A patient reports a family history of age-related macular degeneration (AMD). How should this be documented?

Under Family History noting the relationship and condition (Correct answer)
Under Past Medical History as a chronic condition
Under Review of Systems as a positive finding
Under Social History as an environmental risk factor

Correct answer: Under Family History noting the relationship and condition

Family history (FH) is the section used to record heritable or familial diseases among blood relatives. AMD has a genetic component, so documenting the affected family member's relationship (e.g., mother, sibling) and the condition under FH is the correct approach.

Question 169: What instrument is used to measure the curvature of the anterior corneal surface?

Tonometer
Ophthalmoscope
Retinoscope
Keratometer (Correct answer)

Correct answer: Keratometer

A keratometer measures the curvature of the anterior corneal surface in two principal meridians.

Question 170: When recording the history of present illness (HPI) for a patient reporting blurred vision, which element describes the QUALITY of the symptom?

'Described as foggy, like looking through frosted glass' (Correct answer)
'Worsens when reading'
'Accompanied by mild eye redness'
'Started two weeks ago'

Correct answer: 'Described as foggy, like looking through frosted glass'

Quality describes the character of the symptom — what it feels or looks like. 'Foggy, like looking through frosted glass' is a qualitative descriptor. Onset, modifying factors, and associated symptoms are separate HPI elements.

Question 171: When pupils are of unequal size it is called:

Astigmatism
Anisocoria (Correct answer)
Myopia
Mydriasis

Correct answer: Anisocoria

Explanation: Anisocoria specifically describes unequal pupil sizes.

Question 172: A child is found to have a right esotropia measuring 30 prism diopters by the prism and alternate cover test. The child is 3 years old. What is the MOST important reason to treat this promptly?

To reduce intraocular pressure
To strengthen the extraocular muscles
To prevent astigmatism from developing
To prevent amblyopia from developing in the deviated eye (Correct answer)

Correct answer: To prevent amblyopia from developing in the deviated eye

In young children, strabismus causes the brain to suppress the input from the deviated eye to avoid diplopia. Prolonged suppression during the critical period of visual development leads to amblyopia (lazy eye) — a reduction in best corrected visual acuity that can become permanent if untreated.

Question 173: In the SOAP note format, where would the ophthalmic assistant's measurement of the patient's visual acuity and intraocular pressure be documented?

Subjective
Plan
Objective (Correct answer)
Assessment

Correct answer: Objective

The 'Objective' section of a SOAP note contains all the measurable and observable data collected during the examination, such as visual acuity (VA) and intraocular pressure (IOP).

Question 174: Which parameter is most important when fitting a toric soft contact lens?

The base curve radius only
The back vertex power of the spherical component only
The axis orientation and stabilization mechanism to minimize lens rotation (Correct answer)
The lens overall diameter and water content

Correct answer: The axis orientation and stabilization mechanism to minimize lens rotation

For toric soft lenses, controlling lens rotation and maintaining correct axis alignment is critical, since even a small amount of rotation away from the prescribed axis significantly reduces astigmatic correction.

Question 175: A new patient presents for a comprehensive eye exam. During the history taking, the assistant learns the patient's father has glaucoma. Where in the SOAP note or patient record should this information be primarily documented?

Review of Systems (ROS)
Chief Complaint (CC)
History of Present Illness (HPI)
Family History (FH) (Correct answer)

Correct answer: Family History (FH)

Information about medical conditions affecting blood relatives, especially inheritable eye diseases like glaucoma, is documented in the Family History section. This helps the physician assess the patient's risk factors for developing similar conditions.

Question 176: Aqueous humor is produced by which ocular structure?

Trabecular meshwork
Iris
Ciliary body (Correct answer)
Choroid

Correct answer: Ciliary body

The ciliary body produces aqueous humor through active secretion and passive ultrafiltration from ciliary processes.

Question 177: A visual field test shows a dense arcuate scotoma extending from the blind spot in the superior field of the right eye. This is MOST consistent with which condition?

Retinal detachment in the inferior right eye
Optic nerve fiber layer damage from glaucoma (Correct answer)
AMD affecting the right macula
Homonymous hemianopia from a right occipital cortex lesion

Correct answer: Optic nerve fiber layer damage from glaucoma

Arcuate (Bjerrum) scotomas follow the curved path of nerve fiber bundles from the optic disc and are the hallmark visual field defect of glaucomatous optic nerve damage.

Question 178: Which statement is TRUE pertaining to the use of plain gut sutures?

The sutures have a low tendency toward tissue vascularization
The sutures are absorbable (Correct answer)
The sutures are sunthetic
The sutures provide strobe tensile strength predictability

Correct answer: The sutures are absorbable

Explanation: Plain gut sutures are absorbable, meaning they are gradually broken down and digested by the body's enzymes over time. This characteristic makes them suitable for use in tissues where permanent support is not required.

Question 179: Under HIPAA regulations, which of the following is considered a permissible disclosure of Protected Health Information (PHI) without the patient's explicit authorization?

Providing a patient's diagnosis to their employer for work-related reasons.
Sharing a patient's chart with a pharmaceutical representative.
Confirming a patient's appointment to a caller who provides the patient's name.
Releasing information to another healthcare provider for treatment continuity. (Correct answer)

Correct answer: Releasing information to another healthcare provider for treatment continuity.

HIPAA allows for the disclosure of PHI for Treatment, Payment, and Operations (TPO). Sharing information with another provider involved in the patient's care falls under the 'Treatment' category and is permissible to ensure continuity and quality of care. The other options represent improper disclosures.

Question 180: The Amsler grid is specifically used to detect abnormalities in:

Contrast sensitivity
Color vision deficiency
Peripheral visual field
Central macular function (Correct answer)

Correct answer: Central macular function

The Amsler grid detects metamorphopsia and central scotomas within the central 20 degrees of the visual field.

Question 181: The slit lamp biomicroscope is primarily used to examine which ocular structures?

Only the retina
Anterior and posterior segments of the eye (Correct answer)
Only the optic nerve
Only the corneal surface

Correct answer: Anterior and posterior segments of the eye

The slit lamp provides magnified illuminated examination of both anterior and posterior eye segments.

Question 182: Which item is not designated as a version?

Sursumversion
Levoversion
Dextroversion
Intraversion (Correct answer)

Correct answer: Intraversion

Explanation: "Intraversion" is indeed not a designation of a version. The prefix "intra-" typically denotes movement inward or within. In the context of eye movements, "intra-" usually refers to convergence, the inward movement of both eyes toward each other.

Question 183: When testing visual acuity in a child using the Tumbling E chart, what does the child need to indicate?

The direction the 'legs' of the letter E are pointing (Correct answer)
Whether the image is clear or blurry
The letter that matches a card they are holding
The number of fingers the examiner is holding up

Correct answer: The direction the 'legs' of the letter E are pointing

The Tumbling E chart is used for patients who cannot name letters. The child indicates — by pointing fingers or using a hand-held card — the direction the 'legs' of the letter E point (up, down, left, or right).

Question 184: A patient reports diplopia that is WORSE when looking down and to the left. Which cranial nerve palsy is MOST likely?

Right CN III (oculomotor) palsy
Right CN IV (trochlear) palsy (Correct answer)
Left CN VI (abducens) palsy
Left CN IV (trochlear) palsy

Correct answer: Right CN IV (trochlear) palsy

The right superior oblique (CN IV) primarily depresses and intorts the eye. Diplopia that worsens in downgaze (especially when adducted, i.e., looking left with the right eye) is the classic presentation of a right CN IV palsy.

Question 185: During a cover-uncover test on a new patient, the assistant covers the patient's right eye. The uncovered left eye then moves inward (nasally) to pick up fixation. This finding indicates the presence of a:

Left Exotropia (Correct answer)
Right Hypertropia
Left Esotropia
Right Esophoria

Correct answer: Left Exotropia

The cover-uncover test is used to detect a manifest strabismus (tropia). If the uncovered eye moves to take up fixation when the other eye is covered, a tropia is present in that uncovered eye. Since the left eye was initially deviated outward (exo-) and had to move inward to fixate, the patient has a left exotropia.

Question 186: What does the base curve of a contact lens describe?

The total diameter of the lens
The oxygen permeability of the lens material
The curvature of the central posterior surface of the lens (Correct answer)
The power of the lens in diopters

Correct answer: The curvature of the central posterior surface of the lens

The base curve describes the radius of curvature of the central posterior (back) surface of the contact lens, which determines how the lens fits against the cornea.

Question 187: The Humphrey Visual Field Analyzer performs which type of perimetry?

Amsler grid testing
Static automated perimetry (Correct answer)
Goldmann bowl perimetry
Kinetic perimetry only

Correct answer: Static automated perimetry

The Humphrey Field Analyzer uses static automated perimetry, presenting stationary stimuli at varying intensities.

COA — Certified Ophthalmic Assistant Exam

The JCAHPO COA exam certifies ophthalmic assistants in clinical skills including visual assessment, tonometry, keratometry, pharmacology, and patient care in ophthalmology practices.

200

Questions

180 min

Time Limit

72%

To Pass

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