Ocular Motility Evaluation & Binocular Vision Assessment Flashcards
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Read the first 7 Ocular Motility Evaluation & Binocular Vision Assessment flashcards as text
The Bielschowsky head tilt test is positive (hypertropia increases on ipsilateral head tilt) with palsy of which muscle?
Answer: Ipsilateral superior oblique
On ipsilateral head tilt, the ipsilateral superior oblique and superior rectus are stimulated; if the superior oblique is paretic, the superior rectus acts unopposed causing hypertropia.
Which finding on prism alternate cover test (PACT) suggests a restrictive etiology rather than a paretic one?
Answer: Forced duction test positive
A positive forced duction test (resistance to passive eye movement) confirms mechanical restriction rather than muscle paresis.
Stereopsis of 40 seconds of arc corresponds to which clinical level?
Answer: Fine (central) stereopsis consistent with normal binocular vision
40 arcsec is near-normal fine stereoacuity, consistent with intact bifoveal binocular vision.
In Duane retraction syndrome type I, which finding is characteristic on attempted adduction?
Answer: Globe retraction and narrowing of the palpebral fissure
Type I Duane syndrome shows limited abduction and, on adduction, globe retraction with palpebral fissure narrowing due to co-contraction of horizontal recti.
Which motility finding is pathognomonic for internuclear ophthalmoplegia (INO)?
Answer: Ipsilateral adduction deficit with contralateral abducting nystagmus
INO results from a medial longitudinal fasciculus lesion causing ipsilateral adduction failure and dissociated nystagmus in the contralateral abducting eye.
When measuring a vertical deviation with the prism alternate cover test, prisms are placed:
Answer: Base-up before the hypertropic eye
To neutralize a hypertropia, a base-up prism (apex down) is placed before the higher eye to redirect the image downward.
The red glass test reveals diplopia with the red image displaced to the patient's left. The paretic muscle is most likely the:
Answer: Right lateral rectus
In horizontal diplopia, the false (peripheral) image is on the side of the paretic muscle; a red glass before the right eye with the red image to the left indicates right lateral rectus palsy.