COA Visual Assessment and Testing 2 — Questions and Answers

Question 1: When testing visual acuity in a child using the Tumbling E chart, what does the child need to indicate?

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

The Tumbling E (or illiterate E) chart displays the letter E in four orientations. It is used for pre-literate children, patients with language barriers, or cognitively impaired individuals. The patient indicates the direction of the E's legs by pointing their own fingers or using a hand-held E card as a reference. It is valid for children as young as 3–4 years who have been briefly trained. HOTV charts (matching letters) and Allen pictures are other alternatives for young children.

Question 2: What is the purpose of a pinhole occluder during visual acuity testing?

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

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.

The pinhole occluder contains one or more small holes (usually 1.2 mm diameter) that restrict light rays entering the eye to a narrow central pencil. These paraxial rays require minimal focusing regardless of refractive error, so blur due to myopia, hyperopia, or astigmatism is reduced. If BCVA improves by two or more Snellen lines with pinhole, the loss is likely uncorrected refractive error. Lack of improvement suggests media opacity (cataract, corneal scar) or retinal/optic nerve pathology. The pinhole is used as an adjunct — not a replacement — for refraction.

Question 3: The Ishihara color vision test primarily screens for deficiencies in which color axis?

Blue-yellow (tritan) defects
Red-green defects (protan and deutan) (Correct answer)
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.

The Ishihara test consists of pseudoisochromatic plates with numbers or paths embedded in colored dots. Individuals with normal color vision see the number; those with red-green defects cannot distinguish the figure from the background. It detects protanopia/protanomaly (L-cone deficiency, red-blind) and deuteranopia/deuteranomaly (M-cone deficiency, green-blind). It does NOT reliably detect blue-yellow (tritan) defects or acquired color vision loss from optic nerve disease. For tritan or acquired defects, the Farnsworth D-15 or Farnsworth-Munsell 100-Hue test is preferred.

Question 4: A patient's near vision is tested with a near card and documented as J3 at 40 cm. What does this indicate?

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

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.

Near visual acuity is often measured with Jaeger cards, which display paragraphs of progressively larger type labeled J1 (finest) through J14+ (largest). J1 approximates 20/20 near equivalent. J3 approximates 20/30–20/40 near. The test distance must always be documented (typically 14 inches / 35–40 cm) because apparent acuity changes with distance. Near cards can also use metric M notation or reduced Snellen. Jaeger testing evaluates reading vision and is particularly important when assessing presbyopia and the near add in bifocals.

Question 5: 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?

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

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.

Confrontation visual field testing is a gross screening method. Common techniques include: (1) finger counting — the patient counts fingers presented in each quadrant; (2) finger motion/wiggle — the examiner wiggles one or two fingers and the patient indicates detection; (3) comparison — the patient compares brightness or color intensity between eyes. The motion confrontation technique detects large field defects (hemianopsias, quadrantanopsias). It is less sensitive than automated perimetry but is fast, requires no equipment, and is useful for patients who cannot comply with formal perimetry.

Question 6: Which of the following BEST describes the proper test distance for standard Snellen distance visual acuity testing?

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

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.

Snellen visual acuity fractions are expressed as test distance over the distance at which the letter subtends 5 arc minutes (the size a normal eye resolves). The numerator 20 feet (6 m) is the standard test distance — beyond this, accommodation has minimal effect on distance acuity measurement. Charts placed at less than 20 feet require a correction factor or use of a mirror system. When mirror-back lanes are used, verify the total optical path equals 20 feet. Failure to use the correct distance can result in overcalling or undercalling refractive error.

COA Visual Assessment and Testing 2

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