10 question Quiz: Pupils, APD Testing, Unequal Pupils, and What They Can Mean
1. Why are pupils an important part of an eye exam?
A. They only show whether someone needs glasses
B. They can give clues about the optic nerve, retina, brainstem pathways, and nervous system
C. They only help diagnose dry eye
D. They are mainly checked for cosmetic reasons
2. Unequal pupils are called:
A. Diplopia
B. Ptosis
C. Anisocoria
D. Mydriasis
3. If anisocoria is worse in bright light, which pupil is usually abnormal?
A. The smaller pupil
B. The larger pupil
C. Both pupils equally
D. Neither pupil
4. If anisocoria is worse in the dark, which pupil is usually abnormal?
A. The smaller pupil
B. The larger pupil
C. The pupil with better constriction
D. The pupil on the dominant eye
5. A relative afferent pupillary defect, or RAPD/APD, is most often associated with:
A. Dry eye disease
B. Cataracts only
C. Asymmetric optic nerve disease or severe asymmetric retinal disease
D. Nearsightedness
6. Which test is used to check for an APD?
A. Cover test
B. Swinging flashlight test
C. Color vision plate only
D. Refraction test
7. During an APD response, what happens when light is moved from the normal eye to the affected eye?
A. Both pupils constrict more strongly
B. Both pupils may dilate or constrict less
C. Only the affected pupil changes color
D. The eyelid always closes
8. A large, poorly reactive pupil with ptosis, double vision, pain, or restricted eye movements may suggest:
A. A pupil-involving third nerve palsy
B. Mild dry eye
C. Normal aging
D. Simple eye strain
9. Horner syndrome classically includes:
A. Large pupil, severe glare, and eye redness
B. Small pupil, mild ptosis, and sometimes decreased sweating
C. Equal pupils with no eyelid change
D. Double vision only when reading
10. Which finding is a red flag that may require urgent evaluation?
A. Longstanding mild anisocoria with no symptoms
B. New anisocoria with severe headache, double vision, ptosis, trauma, or neurologic symptoms
C. Slightly smaller pupils in bright light
D. Pupils that constrict normally in both eyes
Pupils Answer Key
B. They can give clues about the optic nerve, retina, brainstem pathways, and nervous system
The pupil response depends on several neurologic pathways. Abnormal pupil size or reactivity can help identify problems involving the retina, optic nerve, cranial nerves, or autonomic nervous system.
C. Anisocoria
Anisocoria means the pupils are different sizes. A small amount can be normal, but new or significant anisocoria may need further evaluation.
B. The larger pupil
If anisocoria becomes more noticeable in bright light, the larger pupil may not be constricting normally. This can point toward a parasympathetic problem, such as a third nerve palsy or Adie tonic pupil.
A. The smaller pupil
If anisocoria becomes more obvious in the dark, the smaller pupil may not be dilating normally. This pattern can occur with Horner syndrome.
C. Asymmetric optic nerve disease or severe asymmetric retinal disease
An APD usually indicates that one eye is sending a weaker light signal to the brain. Optic nerve disease is a common cause, although significant asymmetric retinal disease can also produce an APD.
B. Swinging flashlight test
The swinging flashlight test compares the afferent light response between the two eyes. The examiner moves the light back and forth while observing how both pupils respond.
B. Both pupils may dilate or constrict less
When the light moves to the eye with an APD, the brain receives a weaker afferent signal. As a result, both pupils may constrict less and appear to dilate relative to their previous size.
A. A pupil-involving third nerve palsy
he third cranial nerve controls several eye muscles, the upper eyelid, and pupil constriction. A large poorly reactive pupil combined with ptosis or abnormal eye movements can be an emergency, particularly when pain or headache is present.
B. Small pupil, mild ptosis, and sometimes decreased sweating
Horner syndrome results from disruption of the sympathetic nerve pathway. Typical findings include miosis, mild ptosis, and sometimes decreased facial sweating on the affected side.
B. New anisocoria with severe headache, double vision, ptosis, trauma, or neurologic symptoms
Sudden pupil changes accompanied by neurologic or eye movement symptoms can indicate a serious underlying condition. These findings warrant prompt medical evaluation.
Extra Credit: Clinical Pupil Quiz
1. A patient has anisocoria that is greater in the dark. The smaller pupil also has mild ptosis. What is the most likely diagnosis?
A. Adie tonic pupil
B. Horner syndrome
C. Third nerve palsy
D. Pharmacologic dilation
2. A patient presents with a dilated pupil, ptosis, and the eye positioned “down and out.” What should be suspected?
A. Optic neuritis
B. Horner syndrome
C. Third cranial nerve palsy
D. Physiologic anisocoria
3. Which condition is most likely to produce a relative afferent pupillary defect?
A. Mild cataract
B. Optic neuritis
C. Presbyopia
D. Uncorrected astigmatism
4. A patient has a large pupil that constricts slowly to light but demonstrates better constriction with near fixation. What is the most likely diagnosis?
A. Adie tonic pupil
B. Horner syndrome
C. Argyll Robertson pupil
D. Physiologic anisocoria
5. Which medication can cause pharmacologic mydriasis?
A. Pilocarpine
B. Atropine
C. Brimonidine
D. Timolol
6. A patient has a dense unilateral cataract but otherwise healthy retina and optic nerve. Would you typically expect an RAPD?
A. Yes, a large RAPD
B. Yes, but only in bright light
C. No
D. Only if the pupil is dilated
7. During the swinging flashlight test, both pupils constrict when the light is placed over the right eye but both dilate slightly when it is moved to the left eye. What does this indicate?
A. Right RAPD
B. Left RAPD
C. Right third nerve palsy
D. Left Horner syndrome
8. Which finding most strongly suggests physiologic anisocoria rather than neurologic disease?
A. Sudden onset anisocoria with diplopia
B. Anisocoria associated with ptosis
C. Longstanding small anisocoria with equal reactivity and no symptoms
D. Anisocoria associated with severe headache
9. A patient has anisocoria that is significantly greater in bright illumination. Which pathway should receive particular attention?
A. Sympathetic pathway to the iris dilator
B. Parasympathetic pathway to the iris sphincter
C. Optic tract only
D. Vestibular pathway
10. A patient develops sudden anisocoria, severe headache, ptosis, diplopia, and limited ocular motility. What is the most appropriate next step?
A. Recheck the pupils in six months
B. Prescribe artificial tears
C. Recommend routine neurologic follow-up
D. Arrange urgent emergency neurovascular evaluation
Extra Credit Pupils Answer Key
Answer: B. Horner syndrome
Explanation: Horner syndrome causes impaired sympathetic innervation, producing miosis and mild ptosis. The anisocoria becomes more noticeable in the dark because the affected pupil fails to dilate normally.
Answer: C. Third cranial nerve palsy
Explanation: CN III innervates most extraocular muscles, the levator muscle, and parasympathetic fibers controlling pupil constriction. A pupil-involving third nerve palsy can be associated with compressive lesions and warrants urgent evaluation.
Answer: B. Optic neuritis
Explanation: Optic neuritis impairs afferent input from the affected eye and commonly produces an RAPD when the disease is asymmetric.
Answer: A. Adie tonic pupil
Explanation: Adie pupil typically demonstrates light-near dissociation, meaning the pupil responds poorly to light but better to near stimulation. The affected pupil is often larger.
Answer: B. Atropine
Explanation: Atropine blocks muscarinic receptors in the iris sphincter, resulting in pupil dilation and cycloplegia.
Answer: C. No
Explanation: Media opacity alone typically does not cause an RAPD because the afferent pathway remains intact. Significant retinal or optic nerve asymmetry is more concerning for an RAPD.
Answer: B. Left RAPD
Explanation: Moving the light to the affected left eye produces a weaker afferent signal, causing both pupils to constrict less or appear to dilate.
Answer: C. Longstanding small anisocoria with equal reactivity and no symptoms
Explanation: Physiologic anisocoria is common and generally stable over time. Both pupils remain reactive, and there are no associated neurologic findings.
Answer: B. Parasympathetic pathway to the iris sphincter
Explanation: When anisocoria is greater in bright light, the larger pupil is generally the abnormal pupil because it is failing to constrict appropriately.
Answer: D. Arrange urgent emergency neurovascular evaluation
Explanation: A painful, pupil-involving third nerve palsy can be associated with a posterior communicating artery aneurysm or other serious neurologic pathology. This presentation requires urgent evaluation.
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