Ophthalmology Flashcards
Where is aqueous hummour found?
Only in ant segment
What are the roles of the ciliary body?
Controls iris
Controls shape of lense
Secretes aqueous humour
What 4 classes of drugs are used in glaucoma treatment? and how do they work?
Prostaglandins (increase outflow)
Beta-blockers (decreasee production)
Carbonic anhydrase inhibitors (decrease production)
Sympathomimetics (increase outflow)
Example of carbonic anhydrase inhibitor
Acetozolamide
Which drugs CONSTRICT the pupil? Give an example
Parasympathomimetics (e.g. Pilocarpine)
Which drugs DILATE the pupil? Give an example
Mydriatics (e.g. tropicamide, cyclopentalate)
Sympathomimetics (e.g. adrenaline)
Which drug can cause aculopathy?
Chloroquine (used for rheumatoid + malaria)
Most common causative organism in endopthalmitis
S. epidermis (commensal post cataract surgery)
Causes of acute red eye
Endopthalmitis Acute angle closure glaucoma Scleritis Episcleritis Orbital cellulitis
Management of acute angle closure glaucoma
IV Diamox (Acetozolamide)
Topical anti-HTN (mannitol)
Topical steroids
Pilocarpine drop once IOP <50mmHg
YAG laser peripheral iridotomy
How to differentiate between scleritis + episcleritis?
Phenylephinephrine
- vessels stay red = SCLERITIS
- completely blanches - EPISCLERITIS
Cause of scleritis
CTD (always investigate further)
Causative organisms in orbital cellulitis
H. influenzae, S. aureus, S. pneumonaie
direct extension from sinuses
Management of orbital cellulitis
Broad spectrum abx (ceft, fluclox, met)
Investigation for herpes simplex keratitis
Fluroscein (linear branching dendritic ulcer)
Causes of bacterial conjunctivitis
Pneumococcus
S. aureus
H. influenzae (kids)
Management of bacterial conjunctivitis
Mid - mod = erythromycin
mod-sev = ofloxacin
Gonorrhoeal = ceftriaxone + doxycycline Chlamydial = ophthalmic azithromycin + doxycycline
Presentation in itreous haemorrhage
Painless unilateral loss of vision
Acute
Floaters/shadows/dark spots on vision
Cause of acute visual loss
Vitreous haemorrhage
Retinal detachment
Central retinal artery occlusion
Central retinal vein occlusion
4 F’s of retinal detachment
Floaters Flashes Field loss Fall in acuity (Painless)
Presentation of central retinal artery occlusion
Painless unliateral loss of vision
RAPD
Pale, oedematous macula with cherry red spot
Management of central retinal artery occlusion
Aim to dislodge clot
- ocular massage
- paper bag breathing
- IV acetalzoloamide
Management of central retinal vein occlusion
No ischaemia = observe for 3m
Ischaemia = observe 4-6 wks
Neovascularisation = pan retinal photocoagulation
Cause of gradual visual loss
C - Cataracts A - ARMD (dry) R - Refractive error D - Diabetic retinopathy I - Inherited (retinitis pigemntosum) G - Gaucoma A - Access to eye clinic N - Non-urgent
Presentation of dry ARMD
Gradual central visual loss
Drusen (calcium deposits - signifies corneal degeneration)
Presentation of wet ARMD
SUDDEN central visual loss
Management of wet ARMD
Anti-VEGF (e.g. ranibizumab) - prevents new vessel growth
What does RAPD mean?
Problem with potic nerve communicating to brain
Cause of fixed miotic pupil - what is this assoc with?
Argyll-Robertson pupil - assoc. with neurosyphillis
What is Siedels test?
In trauma - fluroscein will be diluted as it leaks back to front of eye
Management/follow-up of diabetic retinopathy
No retinopathy = screen 12m
Mild non-proliferative = rescreeen 12m
Mod non-proliferative = re-screen 6m
Sev non-proliferative = refer to ophthalm
Proliferative = URGENT refferral + retinal laser photocoagulation
Classification of non-proliferative diabetic retinopathy
Mild = only microneurysms >1 dot haemmorhage Mod = 4+ haemorrhages - but not in all 4 quadrants Sev = "busy fundus" - large amount in all 4 quadrants
