Binocular Vision & Strabismus Flashcards

The Hirschberg corneal light reflex test is primarily used to estimate the angle of which condition?

Answer: Strabismus

The Hirschberg test uses the position of the corneal light reflex relative to the pupil center to estimate the angle of deviation in strabismus.

In esotropia, the deviating eye turns in which direction?

Answer: Inward (nasal)

Esotropia is an inward (nasal/medial) deviation of the eye, commonly called 'crossed eyes.'

Which term describes a latent ocular deviation that is controlled by fusion and only becomes manifest when fusion is disrupted?

Answer: Phoria

A phoria (heterophoria) is a latent deviation kept latent by fusional vergence, only revealed by dissociation techniques such as the cover test.

The cover-uncover test is the most reliable clinical method to distinguish between a tropia and a phoria because it:

Answer: Disrupts fusion, revealing any manifest deviation in the covered eye

When one eye is covered, fusional vergence is disrupted; a refixation movement of the uncovered eye upon removal of the cover indicates a tropia, while movement of the covered eye on cover removal indicates a phoria.

A positive result on the Randot Stereotest indicates:

Answer: Bifoveal fixation and intact binocular vision

Passing the Randot Stereotest demonstrates bifoveal fixation and functional binocular vision with intact stereopsis.

The angle kappa is defined as the angle between the:

Answer: Pupillary axis and the visual axis

Angle kappa is the angle between the pupillary axis (perpendicular to the cornea through the center of the pupil) and the visual axis (fovea to fixation point).

The prism adaptation test (PAT) is used preoperatively in strabismus patients primarily to:

Answer: Reveal the full angle of deviation before surgery

PAT uses a prism to neutralize the deviation; if the angle increases under the prism (prism adaptation), it reveals the full underlying deviation and improves surgical outcomes.