Ocular Motility and Alignment Flashcards
6 cards from real COA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Ocular Motility and Alignment flashcards as text
The Worth 4-Dot test uses a flashlight with four illuminated circles (one red on top, two green on the sides, one white on the bottom). The patient wears red-green glasses. If the patient reports seeing four dots, what does this indicate?
Answer: Normal binocular fusion
Seeing all four dots (one red, two green, one white/mixed) indicates both eyes are contributing to the visual percept and the patient has binocular fusion at the tested distance.
In Hess screen or Lees screen testing, which muscle is identified as the UNDERACTING muscle when a patient's field plot is smaller on the right side?
Answer: The right eye muscles (ipsilateral underaction)
In Hess/Lees screen testing, the eye with the smaller field plot has the underacting (paretic) muscles. A smaller right-side field indicates right eye muscle underaction (paresis), while the left eye shows secondary overaction (larger field) due to Hering's law.
During the swinging flashlight test (RAPD test), the examiner swings a light between the two eyes every 2–3 seconds and observes the pupillary responses. A relative afferent pupillary defect (RAPD) in the right eye is indicated by:
Answer: Both pupils dilate when the light moves from the left eye to the right eye
A RAPD in the right eye means the right optic nerve transmits less light signal. When light swings to the right eye, both pupils receive a weaker 'bright light' signal and dilate — the right pupil appears to dilate when directly illuminated, which is the pathological finding.
A patient with a right CN VI (abducens) palsy will show which characteristic finding on ocular motility testing?
Answer: Right eye cannot abduct in right gaze
CN VI innervates the ipsilateral lateral rectus muscle. A right CN VI palsy causes weakness of right eye abduction (inability to move the right eye laterally/temporally), resulting in esotropia worst in right gaze.
Which maneuver is used during the Maddox rod test to quantify the amount of vertical phoria?
Answer: Placing the Maddox rod horizontally over one eye and using vertical prisms to neutralize the perceived line displacement
For vertical phoria measurement, the Maddox rod is placed horizontally over one eye, converting the point light into a vertical line. Prism is then added to neutralize the separation between the light and the line — the prism power required equals the phoria.
What is the purpose of the Brückner test (red reflex comparison) in pediatric eye exams?
Answer: To screen for asymmetric red reflexes that may indicate strabismus, amblyopia, or media opacities
The Brückner test uses a direct ophthalmoscope at ~1 meter to compare the red reflexes of both eyes simultaneously. Asymmetry in brightness or color can indicate strabismus, anisometropia, amblyopia risk, or media opacities (cataract, corneal scar).