CPO Clinical Principles and Procedures 1 — Questions and Answers
Question 1: Which of the following is used to measure intraocular pressure (IOP)?
- Autorefractor
- Tonometer (Correct answer)
- Phoropter
- Keratometer
Correct answer: Tonometer
A tonometer is the instrument specifically used to measure intraocular pressure (IOP), which is the fluid pressure inside the eye. This measurement is a critical screening tool for detecting and monitoring glaucoma, a condition that can lead to optic nerve damage and vision loss.
Question 2: What is the primary purpose of performing retinoscopy during a patient examination?
- Measuring intraocular pressure
- Determining the refractive error of the eye (Correct answer)
- Assessing binocular vision
- Evaluating the health of the optic nerve
Correct answer: Determining the refractive error of the eye
Retinoscopy is an objective method used during an eye examination to determine the refractive error of the eye, meaning whether a person is nearsighted, farsighted, or has astigmatism. By observing the light reflex from the retina, the examiner can accurately estimate the necessary lens prescription without requiring patient feedback, which is especially useful for children or non-verbal individuals.
Question 3: What does a patient’s visual acuity of 20/40 indicate?
- The patient sees at 40 feet what a normal person sees at 20 feet.
- The patient sees at 20 feet what a normal person sees at 40 feet. (Correct answer)
- The patient has perfect vision.
- The patient’s vision cannot be corrected.
Correct answer: The patient sees at 20 feet what a normal person sees at 40 feet.
A visual acuity of 20/40 indicates that the patient sees at 20 feet what a person with normal vision would typically see at 40 feet. This means their vision is less sharp than average, requiring them to be closer to an object to see it as clearly as someone with 20/20 vision would from further away.
Question 4: Which pre-test procedure determines the prescription power of the patient’s glasses?
- Pachymetry
- Lensometry (Correct answer)
- Tonometry
- Visual Field Testing
Correct answer: Lensometry
Lensometry is the pre-test procedure used to measure the prescription power of a patient's existing eyeglasses. This helps the optometrist determine the current correction being worn, which is essential for comparison with new findings and for verifying the accuracy of new lenses.
Question 5: What is the purpose of the cover test in clinical practice?
- To check for refractive errors
- To assess for strabismus or binocular alignment (Correct answer)
- To evaluate pupil response
- To determine intraocular pressure
Correct answer: To assess for strabismus or binocular alignment
The cover test is a crucial clinical procedure used to assess for strabismus (an eye turn) or any subtle misalignment of the eyes. By alternately covering and uncovering each eye, the examiner can observe any movement of the uncovered eye, indicating a deviation in binocular alignment.
CPO Clinical Principles and Procedures 1
Which of the following is used to measure intraocular pressure (IOP)?