Ophthalmology

Question 1

What is innervation of constrictor pupillae?

Answer 1

PNS by M3-muscarinic ACh receptors

Question 2

What is innervation of dilator pupillae?

Answer 2

SNS by alpha-1 adrenoreceptors

Question 3

Pilocarpine mechanism of action?

Answer 3

M3-muscarinic agonist –> pupil constriction eg Adie’s tonic pupil

Question 4

Treatment glaucoma

Answer 4

Pilocarpine - contraction ciliary muscles –> opens outflow via trabecular meshwork
Reduced aqueous production - topical beta blockers eg Timolol, acetazolamide

Question 5

Asthma medication causing pupil dilatation / anisocoria

Answer 5

Ipratropium bromide. Blown in during NEBS

Question 6

Symptoms of Horner’s Syndrome

Answer 6

Miosis, ptosis, anhydrosis
Disruption of SNS supply to the eye

Question 7

How do you confirm Horner’s syndrome?

Answer 7

Cocaine eye drops –> won’t dilate pupil in Horner’s (lack of SNS supply to eye).
Apraclonidine 1% –> dilation of pupil

Question 8

What drugs are used as intravitreal anti-VEGF

Answer 8

Bevacizumab
Ranibizumab

Question 9

What is ambylopia?

Answer 9

Permanent visual loss due to brain neglecting eye

Question 10

Pathophysiology and features of cataracts

Answer 10

Abnormal drainage via trabecular network –> raised IOP
May be genetic (CYP1B1 gene), Sturge-Webber or steroids
Sx: photophobia, corneal opacification
Signs: Optic disc cupping, enlarged optic disc, raised IOP
Tx: early surgery

Question 11

Presentation of different forms of retinal dystrophies

Answer 11

Rod dystrophies - poor peripheral and night vision
Cone dystrophies - poor colour and acuity
Macular dystrophies - poor central + colour vision

Question 12

What is myopia and how is it treated?

Answer 12

Short sighted - near objects are clear
Corrected with concave (minus) lens

Question 13

What is hypermetropia and how is it treated?

Answer 13

Long signed - far objects are clear
Corrected with convex (plus) lens

Question 14

What is a concomitant squint and what causes it?

Answer 14

Squint angle is the same in all positions
Causes: refractive, accommodation, poor cortical fusional mechanisms
Esotropia / exotropia / hypertropia / hypotropia

Question 15

What is incomitant squint and what causes it?

Answer 15

Squint angle changes depending on position of gaze
Causes: CN palsy. Congenital disinnervation syndrome, trauma, tumour, raised ICP

Question 16

Causes of nystagmus in children

Answer 16

Infantile sensory - aniridia, albinism
infantile idiopathic motor nystagmus - otherwise NAD
Secondary to neuro disease eg Arnold-Chiari malformation, posterior fossa tumour
Acquired vestibular damage - fast beats away from vestibular disease

Question 17

What is RAPD?

Answer 17

Relative Afferent Pupillary Defect
Swinging light - relative dilatation of both pupils
Causes: Optic neuropathy, optic neuritis, optic nerve compression (orbital tumours or dysthyroid eye disease), trauma, and asymmetric glaucoma.

Question 18

What is anisocoria and what causes it?

Answer 18

= Unequal pupil size
Problem with little pupil (doesn’t dilate in dark) - horner’s, PNS disruption
Problem with large pupil (doesn’t constrict in light) - 3rd nerve palsy, atropine drop, Adie’s tonic pupil (post-viral), post. communicating artery aneurysm, tumour, mass effect