AOC AOC Ocular Motility and Strabismus

Question 1

Which term describes a constant inward deviation of one eye that cannot be controlled by fusional mechanisms?

Accepted Answer

Esotropia

Answer

Esotropia is a manifest inward (convergent) deviation of the eye that is not controlled by fusion.

Question 2

The Hirschberg test estimates the angle of strabismus by observing the position of the corneal light reflex; approximately how many prism diopters does 1 mm of decentration represent?

Accepted Answer

15 PD

Answer

In the Hirschberg test, each 1 mm of corneal light reflex decentration corresponds to approximately 15 prism diopters of deviation.

Question 3

Which type of strabismus is characterized by a larger deviation in one field of gaze than another, suggesting extraocular muscle overaction or underaction?

Accepted Answer

Incomitant strabismus

Answer

Incomitant (non-comitant) strabismus has a deviation that varies depending on the direction of gaze, indicating a muscle restriction or paresis.

Question 4

A patient with a fourth cranial nerve palsy typically shows which type of vertical strabismus?

Accepted Answer

Hypertropia of the ipsilateral eye

Answer

Fourth (trochlear) nerve palsy causes weakness of the superior oblique, leading to hypertropia of the affected eye.

Question 5

Which test isolates each eye using an opaque occluder to detect a manifest deviation (tropia)?

Accepted Answer

Cover-uncover test

Answer

The cover-uncover test detects a tropia by covering one eye and watching the uncovered eye for a corrective movement.

(AOC) American Orthoptic Council Practice Test

(AOC) American Orthoptic Council Practice Test

AOC AOC Ocular Motility and Strabismus