AOC AOC Ocular Motility and Strabismus 1 — Questions and Answers
Question 1: Which term describes a constant inward deviation of one eye that cannot be controlled by fusional mechanisms?
- Esotropia (Correct answer)
- Exotropia
- Hypertropia
- Cyclotropia
Correct answer: Esotropia
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?
- 5 PD
- 10 PD
- 15 PD (Correct answer)
- 22 PD
Correct answer: 15 PD
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?
- Comitant strabismus
- Incomitant strabismus (Correct answer)
- Intermittent strabismus
- Microtropia
Correct answer: Incomitant strabismus
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?
- Hypotropia of the ipsilateral eye
- Hypertropia of the ipsilateral eye (Correct answer)
- Exotropia
- Esotropia
Correct answer: Hypertropia of the ipsilateral eye
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)?
- Alternate cover test
- Simultaneous prism cover test
- Cover-uncover test (Correct answer)
- Maddox rod test
Correct answer: Cover-uncover test
The cover-uncover test detects a tropia by covering one eye and watching the uncovered eye for a corrective movement.
Question 6: Amblyopia secondary to strabismus is most effectively treated when initiated during which period?
- After age 10
- After age 7
- During the sensitive period (before age 7–8) (Correct answer)
- Adulthood only
Correct answer: During the sensitive period (before age 7–8)
Amblyopia treatment is most effective during the visual sensitive period, typically before age 7–8, when neural plasticity is greatest.
AOC AOC Ocular Motility and Strabismus 1
Which term describes a constant inward deviation of one eye that cannot be controlled by fusional mechanisms?