Ophthalmology Flashcards
What is innervation of constrictor pupillae?
PNS by M3-muscarinic ACh receptors
What is innervation of dilator pupillae?
SNS by alpha-1 adrenoreceptors
Pilocarpine mechanism of action?
M3-muscarinic agonist –> pupil constriction eg Adie’s tonic pupil
Treatment glaucoma
Pilocarpine - contraction ciliary muscles –> opens outflow via trabecular meshwork
Reduced aqueous production - topical beta blockers eg Timolol, acetazolamide
Asthma medication causing pupil dilatation / anisocoria
Ipratropium bromide. Blown in during NEBS
Symptoms of Horner’s Syndrome
Miosis, ptosis, anhydrosis
Disruption of SNS supply to the eye
How do you confirm Horner’s syndrome?
Cocaine eye drops –> won’t dilate pupil in Horner’s (lack of SNS supply to eye).
Apraclonidine 1% –> dilation of pupil
What drugs are used as intravitreal anti-VEGF
Bevacizumab
Ranibizumab
What is ambylopia?
Permanent visual loss due to brain neglecting eye
Pathophysiology and features of cataracts
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
Presentation of different forms of retinal dystrophies
Rod dystrophies - poor peripheral and night vision
Cone dystrophies - poor colour and acuity
Macular dystrophies - poor central + colour vision
What is myopia and how is it treated?
Short sighted - near objects are clear
Corrected with concave (minus) lens
What is hypermetropia and how is it treated?
Long signed - far objects are clear
Corrected with convex (plus) lens
What is a concomitant squint and what causes it?
Squint angle is the same in all positions
Causes: refractive, accommodation, poor cortical fusional mechanisms
Esotropia / exotropia / hypertropia / hypotropia
What is incomitant squint and what causes it?
Squint angle changes depending on position of gaze
Causes: CN palsy. Congenital disinnervation syndrome, trauma, tumour, raised ICP
Causes of nystagmus in children
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
What is RAPD?
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.
What is anisocoria and what causes it?
= 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
