Ophthalmology - Pupil abnormalities

Question 1

A 48yo woman presents with a right fixed dilated pupil. What is your differential?

Answer 1

1. pharmacological blockade: anti-cholinergic eye drops e.g. atropine, cyclopentolate, tropicamide
2. Holmes-Adie pupil
3. 3rd nerve palsy
4. traumatic iridoplegia after facial injury
5. congenital

Question 2

What are the characteristic features of a Holmes-Adie pupil?

Answer 2

• dilated pupil is not (or only v. slowly) reactive to light
• slowly reactive to accommodation
• once it has constricted, it remains constricted for a very long time

Benign condition usually seen in women. Bilateral in 20%. If associated with absent ankle/knee reflex = Holmes-Adie syndrome.

Question 3

A 56yo man presents with a painful right fixed dilated pupil. You also notice his right eyelid drooping. Which condition must absolutely be excluded and how would you do this?

Answer 3

‘Surgical’ 3rd nerve palsy: posterior communicating artery aneurysm compressing parasympathetics in superficial 3rd nerve. Features:

• eye down + out
• mydriasis
• ptosis
• often painful

Diagnosis: brain MRI/angiography

Question 4

Suggest drug causes of mydriasis.

Answer 4

• topical mydriatics (anticholinergics): atropine, cyclopentolate, tropicamide
• sympathomimetic drugs: cocaine, amphetamines
• anticholinergic drugs: tricyclic antidepressants

Question 5

A 67yo man presents with non-painful dilated pupils. O/E they fail to react to light but do react to accommodation. What is this sign called? Name 2 possible causes.

Answer 5

Argyll-Robertson pupil:

• neurosyphillis
• diabetic neuropathy

Question 6

Name 4 possible causes for a single constricted pupil.

Answer 6

• parasympathomimetics e.g. pilocarpine eye drops
• Horner’s syndrome: associated ptosis + anhydrosis
• sympathetic lesion
• cluster headaches

Question 7

Suggest drug causes of miosis.

Answer 7

• opioids e.g. morphine, methadone
• antipsychotics e.g. risperidone, haloperidol, quetiapine
• cholinergics e.g. acetycholine

Question 8

Name 4 causes of relative afferent pupillary defect.

Answer 8

Caused by lesions anterior to the optic chiasm, i.e. optic nerve or retina.

• retinal detachment
• optic neuritis e.g. MS
• central retinal artery occlusion or ischaemic central retinal vein occlusion
• optic nerve compression