COT Pupil Assessment 3 — Questions and Answers
Question 1: A COT is assessing a 7-year-old child referred for difficulty copying from the board. Which near vision acuity test is MOST appropriate for this patient?
- Jaeger chart at 14 inches
- Reduced Snellen chart at 14 inches (Correct answer)
- HOTV chart at 14 inches
- Tumbling E chart at 20 feet
Correct answer: Reduced Snellen chart at 14 inches
The reduced Snellen chart at 14 inches is the standard near acuity test for school-age children who know their letters. It measures near visual acuity at the typical reading distance. The Jaeger chart uses print sizes rather than standardized Snellen notation. HOTV and Tumbling E are used for preschool children who cannot identify letters. Tumbling E at 20 feet tests distance, not near acuity.
Question 2: During pupils assessment, a patient has an afferent pupillary defect (APD) in the right eye. When the light swings from the left eye to the right eye, what do you observe in the right pupil?
- The right pupil constricts briskly
- The right pupil dilates or fails to constrict (Correct answer)
- The right pupil remains unchanged
- Both pupils dilate simultaneously
Correct answer: The right pupil dilates or fails to constrict
An afferent pupillary defect (Marcus Gunn pupil) indicates reduced afferent input from the affected eye. When light swings to the eye with the APD, the pupil dilates (or fails to constrict as briskly) because the afferent signal from that eye is weaker than from the normal eye. This is detected using the swinging flashlight test.
Question 3: A COT performs the cover-uncover test on a patient and notices the uncovered eye moves to pick up fixation. What does this finding indicate?
- Orthophoria
- Heterophoria (latent deviation)
- Heterotropia (manifest deviation) (Correct answer)
- Convergence insufficiency
Correct answer: Heterotropia (manifest deviation)
In the cover-uncover test, movement of the UNCOVERED eye when the other eye is covered indicates a heterotropia (manifest strabismus). The uncovered eye was not maintaining fixation, meaning it was deviated. Heterophoria (latent deviation) is detected by the alternate cover test, where the previously covered eye moves upon uncovering. Orthophoria shows no movement.
Question 4: When testing color vision using Ishihara plates, a patient correctly identifies 12 out of 14 plates. How should this result be interpreted?
- Normal color vision
- Mild red-green color deficiency (Correct answer)
- Blue-yellow color deficiency
- Complete achromatopsia
Correct answer: Mild red-green color deficiency
Ishihara plates specifically test for red-green color deficiencies. Passing 12 out of 14 plates falls below the normal threshold (typically 13–14 correct), indicating a mild red-green color deficiency. The Ishihara test does not detect blue-yellow deficiencies (tritan defects), which require the Farnsworth D-15 or similar tests. Complete achromatopsia would result in very few plates being identified correctly.
Question 5: A COT is evaluating a patient's stereopsis using the Randot test. The patient identifies the circle in the gross stereopsis section but fails all contour stereopsis circles. What does this suggest?
- Normal binocular vision with excellent depth perception
- Monocular depth cue use; stereoacuity of 500 seconds of arc or worse (Correct answer)
- Suppression of one eye with no stereopsis
- Anomalous retinal correspondence
Correct answer: Monocular depth cue use; stereoacuity of 500 seconds of arc or worse
The Randot gross stereopsis section uses larger, easier targets detectable with monocular cues or very coarse stereopsis. Failing all contour stereopsis circles but passing gross stereopsis suggests the patient is using monocular cues rather than true binocular fusion, placing their functional stereoacuity at 500 seconds of arc or worse. This may indicate amblyopia, strabismus, or poor binocularity.
Question 6: During confrontation visual field testing, a patient fails to see the examiner's fingers in the superior nasal quadrant of the left eye only. Which condition is MOST consistent with this finding?
- Left homonymous hemianopia
- Bitemporal hemianopia from a pituitary lesion
- An inferior temporal retinal defect in the left eye (Correct answer)
- Right optic tract lesion
Correct answer: An inferior temporal retinal defect in the left eye
Visual field defects follow the rule of retinal inversion: the superior nasal visual field is imaged on the inferior temporal retina. A defect in the superior nasal quadrant of the left eye only (monocular) localizes the lesion anterior to the chiasm — specifically an inferior temporal retinal or optic nerve defect in the left eye. Homonymous hemianopia affects the same side in both eyes. Bitemporal hemianopia affects both temporal fields from chiasmal compression.
COT Pupil Assessment 3
A COT is assessing a 7-year-old child referred for difficulty copying from the board.
Which near vision acuity test is MOST appropriate for this patient?