Ophthalmology

Question 1

What Vitamin toxicity might cause papilloedema?

Answer 1

Vitamin A toxicity

Question 2

What eye drops can be used to confirm a Horner’s pupil?

Answer 2

Apraclonidine eye drops

Question 3

When using apraclonidine eye drops to confirm a Horners pupil, what is seen?

Answer 3

Apraclonidine stimulates alpha 1 & alpha 2 receptors.

Horners pupil: will dilate
(Relative super sensitivity of this pupil to alpha 1)

Normal pupil: constricts
(Due to more portent activity of the alpha 2 receptor which triggers reputable or noradrenaline at synaptic cleft)

Question 4

What does hydroxyamphetamine eye drops do?

Answer 4

Distinguishes between first/ second or third order neurones. Ie. Between lesion in brainstorm/ cervical cord/ chest/ neck vs above the superior cervical ganglion at the carotid bifurcation

Question 5

What effect does hydroxyamphetamine have on pupils in Horner’s?

Answer 5

Normal pupil or first/ second order Horner’s: pupil will dilate (secondary to increased levels of noradrenaline from post synaptic neurones)

Third order Horner’s (ie. post ganglionic- anything above superior cervical ganglion): no dilatation

Question 6

Central causes of Horners syndrome?

Answer 6

• causes anhidrosis of face, arm and trunk
• stroke
• syringomyelia
• multiple sclerosis
• tumour
• encephalitis

Question 7

Pre ganglionic causes of Horner’s syndrome?

Answer 7

• causes anhidrosis of the face.
• pancoast tumour
• thyroidectomy
• trauma
• cervical rib

Question 8

Post ganglionic causes of Horner’s syndrome?

Answer 8

• no anhidrosis
• carotid artery dissection
• carotid artery aneurysm
• cavernous sinus thrombosis
• cluster headache

Question 9

Drug causes of mydriasis?

Answer 9

• topical mydriatics: tropicamide, atropine.
• sympathomimetic drugs: amphetamines, cocaine.
• anticholinergic drugs: tricyclic antidepressants

Question 10

antioxidant dietary supplements contraindicated in what situation?

Answer 10

smokers.

Beta-carotene has been found to increase the risk of lung cancer.

Question 11

Dendritic corneal ulcer

Answer 11

Herpes simplex keratitis most commonly presents with dendritic corneal ulcer.

Mx: topical aciclovir + ophthal referral

Question 12

Features of background diabetic retinopathy?

Answer 12

• microaneurysms (dots)
• blot haemorrhages (<=3)
• hard exudates

Question 13

sudden, painless reduction or loss of visual acuity +

severe retinal haemorrhages on fundoscopy

Answer 13

Central retinal vein occlusion

Question 14

Cherry red spot on pale retina?

Answer 14

Central retinal artery occlusion

Question 15

What electrolyte imbalance may cause papilloedema?

Answer 15

HypoCa, hypoPTH