Pupillary defects

Question 1

Relative afferent pupillary defect

Answer 1

A SIGN NOT A DIAGNOSIS

Relative Afferent Pupillary Defect (RAPD) is a condition in which pupils respond differently to light stimuli shone in one eye at a time due to unilateral or asymmetrical disease of the retina or optic nerve

Causes: optic nerve disorders, demyelination optic neuritis, glaucoma, traumatic optic neuropathy, radiation damage to optic nerve, retinal disease

1. In a dim room, have the patient fixate on a distant point
2. Shine a light in one eye and allow pupil diameter to stabilize, shining the light directly into their eye for about 3 seconds

• Both pupils should constrict equally
  3. Quickly swing the light to the other eye and observe pupil diameter
• If that eye is normal, both pupils will constrict slightly
• If RAPD is present in that eye, both pupils will dilate

4. Quickly swing the light back to the first eye

• If that eye is normal, both pupils will constrict slightly
• If RAPD is present in that eye, both pupils will dilate

Question 2

Holmes adie pupil

Answer 2

Adie syndrome, or Holmes-Adie syndrome, is a rare neurological disorder affecting the pupil of the eye. In most patients the pupil is larger than normal (dilated) and slow to react in response to direct light. Absent or poor tendon reflexes are also associated with this disorder

Common picture: woman with poor pupillary response to light + absent knee or ankle jerks and impaired sweating

Causes: due to viral or bacterial infection that causes inflammation and damage to neurons in ciliary ganglion

Management: reading glasses, not life threatening or disabling

Question 3

Horner’s syndrome

Answer 3

SPAM

S: sympathetic NS

p: ptosis

A: anhydrosis

M: miosis

Also involves enopthalmos - sinking of eye into orbit

Causes: birth trauma to neck/ shoulder, stoke in brainstem, MS, spinal cord tumours/ cysts, apical lung cancer

Management involves management of underlying cause

Question 4

Argyll Robertson pupil

Answer 4

Argyll-Robertson pupil is one of the classic pupillary syndrome. It is sometimes seen in neurosyphilis.

A mnemonic used for the Argyll-Robertson Pupil (ARP) is Accommodation Reflex Present (ARP) but Pupillary Reflex Absent (PRA)

Features

• Small, irregular pupils
• No response to light but there is a response to accommodate

Causes

• Diabetes mellitus
• Syphilis

Management

• Aimed at treating the primary cause of the pupillary abnormality

Question 5

Optic neuropathy

Answer 5

Damage to the optic nerve from any cause

Main symptom is loss of vision, with colors appearing subtly washed out in the affected eye