Sudden Visual Loss

Bilateral occipital infarct; bilateral temporal arteritis; quinine, methanolBilateral

Retinal Artery Occlusion

Causes: thrombotic; embolic (young females, better prognosis, platelet emboli; talc if IVDU; from carotid / heart); temporal arteritis (5%); vasculitis; sickle cell disease; trauma; intraocular pressure; vasospasm; poor outcomeSymptoms: visual loss over seconds; unilateral; painless; progresses from outer field inwardsExamination: RAPD; pale optic disc; cherry red spot (may not be present early); retinal white oedema (may take >24hrs to develop)Management: opthalmological emergency; permanent if >90mins; digital massage; hypercarbia (carbogen = 95% O2, 5% CO2); topical beta-blockers; retrobulbar anaesthesia with lignocaine to relieve vasospasm; carbonic anhydrase inhibitors (acetazolamide 500mg IV stat intraocular pressure); aqueous humour paracentesis if resistant to treatment

Retinal Vein Occlusion

Causes: hyperviscosity, HTN, glaucoma, atherosclerosis, diabetesAssessment: onset over minutes; progresses from outer field inwards; painless; no floaters; can count fingers; thunderstorm retina, dilated tortuous veins, cotton wool spots, disc oedema, RAPDManagement: poor prognosis; prevent neovascularisation

Retinal Detachment

Pathophysiology: rhegmatogenous (most common; associated with retinal tear); tractional (diabetic retinopathy, trauma); exudative (fluid accumulated under tear; neoplastic, inflammatory, vascular); combinedCauses: myopia, cataracts removal, vitreous diseasesAssessment: onset over hours; flashers and floaters; partial field loss like curtain; maybe normal visual acuity if macular not involvedInvestigations: USS 90% sensitivity and specificityManagement: eye pad; bed rest; laser photocoagulation

Vitreous Haemorrhage

Causes: trauma; diabetes (neovascular); coagulopathy; posterior vitreous detachment (shaken baby; incomplete in 40% and attached parts cause traction); retinal detachment; previous retinal vein occlusionAssessment: large black floaters precede hundreds of small black specks cobweb floaters visual loss, sudden, painlessManagement: opthalmology review; admit; bed rest; laser photocoagulation and vitrectomy; recurrence common

Optic Neuritis

Causes: idiopathic; multiple sclerosis; temporal arteritis; HTN; atherosclerosis; Post-vaccination; viral (measles, mumps, chickenpox, infectious mononucleosis); syphilis, TB: sarcoidosis; cryptococcusAssessment: vision (especially colour; progresses over days-weeks); unilateral; eye pain (90%); Uthoff’s phenomenon; visual acuity <6/12; central scotoma; RAPD; optic disc oedema in 50% (not if retrobulbar); small haemorrhages over discManagement: most recover spontaneously; steroids speed recovery and rate of progression to multiple sclerosis in 2yrs, but no long term benefit; multiple sclerosis develops in 20% if normal MRI, 56% if abnormal

Other Optic nerve / chiasm compression; toxic; metabolic; infarct; cancer; AVM; trauma