COT - Certified Ophthalmic Technician Ocular Motility Testing Questions and Answers — Questions and Answers
Question 1: A technician is performing the Worth 4-Dot test on a patient. The patient, wearing red/green glasses (red lens over the right eye), reports seeing five dots (two red and three green). What does this result indicate?
- Normal binocular fusion
- Suppression of the right eye
- Suppression of the left eye
- Diplopia (double vision) (Correct answer)
Correct answer: Diplopia (double vision)
Seeing five dots (two red through the right eye and three green through the left eye) indicates that both eyes are seeing simultaneously but are not fusing the images, resulting in diplopia, or double vision. Normal fusion would result in seeing four dots. Suppression of one eye would lead to seeing only the dots visible to the non-suppressed eye (two red or three green).
Question 2: Which of the following tests is designed to differentiate between a heterophoria and a heterotropia by observing the uncovered eye?
- Hirschberg Test
- Alternate Cover Test
- Cover-Uncover Test (Correct answer)
- Maddox Rod Test
Correct answer: Cover-Uncover Test
The cover-uncover test is specifically used to distinguish between a phoria (a latent deviation that is controlled by fusion) and a tropia (a manifest deviation that is always present). By covering one eye and observing the uncovered eye for movement, a manifest deviation (tropia) can be detected. The alternate cover test breaks fusion and reveals the total deviation (phoria + tropia) but does not differentiate between them.
Question 3: During ocular motility testing, you ask a patient to follow your target with both eyes to the right. This binocular, conjugate movement is referred to as:
- Duction
- Dextroversion (Correct answer)
- Convergence
- Sursumduction
Correct answer: Dextroversion
Versions are binocular eye movements where both eyes move in the same direction. Movement of both eyes to the right is specifically termed dextroversion. Ductions are monocular movements (one eye at a time). Convergence is the simultaneous inward movement of both eyes, and sursumduction is the upward movement of a single eye.
Question 4: A patient presents with an inability to abduct their left eye (turn it outward). A lesion of which cranial nerve is the most likely cause of this deficit?
- Cranial Nerve II (Optic)
- Cranial Nerve III (Oculomotor)
- Cranial Nerve IV (Trochlear)
- Cranial Nerve VI (Abducens) (Correct answer)
Correct answer: Cranial Nerve VI (Abducens)
Cranial nerve VI, the abducens nerve, innervates the lateral rectus muscle, which is solely responsible for abduction (outward movement) of the eye. Therefore, a lesion of CN VI would result in an inability to abduct the eye on the affected side. CN III innervates most of the other extraocular muscles, and CN IV innervates the superior oblique.
Question 5: While performing a Hirschberg test, the technician notes that the corneal light reflex is centered on the patient's right pupil but is displaced temporally (outward) on the cornea of the left eye. This finding is suggestive of:
- Left Exotropia
- Left Esotropia (Correct answer)
- Left Hypertropia
- Orthophoria
Correct answer: Left Esotropia
The Hirschberg test assesses ocular alignment by observing the position of the corneal light reflex. If an eye is turned inward (esotropia), the light reflex will be displaced outward (temporally) from the center of the pupil. Conversely, if the eye were turned outward (exotropia), the reflex would be displaced nasally. Therefore, a temporal displacement of the reflex in the left eye indicates a left esotropia.
Question 6: When evaluating the six cardinal positions of gaze, which two muscles are primarily responsible for moving the eyes into the 'up and right' position (dextroelevation)?
- Right Superior Rectus and Left Inferior Rectus
- Right Lateral Rectus and Left Medial Rectus
- Right Superior Rectus and Left Inferior Oblique (Correct answer)
- Right Superior Oblique and Left Inferior Rectus
Correct answer: Right Superior Rectus and Left Inferior Oblique
In the 'up and right' gaze, the primary elevator of the right eye is the Superior Rectus, and the primary elevator of the adducted left eye is the Inferior Oblique. These two muscles are 'yoke muscles,' meaning they work together to produce a specific conjugate eye movement.
COT - Certified Ophthalmic Technician Ocular Motility Testing Questions and Answers
A technician is performing the Worth 4-Dot test on a patient.
The patient, wearing red/green glasses (red lens over the right eye), reports seeing five dots (two red and three green).
What does this result indicate?