Sudden loss of vision Flashcards
What is non-arteritic ischaemic optic neuropathy?
Ischaemia and infarction of the optic nerve head not caused by arterial inflammation
e.g. by occlusion of the short posterior ciliary arteries
Symptoms of non-AION:
Painless monocular sudden loss of vision
Signs of non-AION:
Moderate-severe decrease in VA (6/12 to 6/60)
Swollen optic nerve with splinter/flame haemorrhages
RAPD
VFD corresponding to area of disc swelling (most commonly inferior altitudinal defects)
Pale disc indicates…
Loss of neural tissue
What happens in GCA?
Vasculitis of medium and large arteries causes AION
Treat with high dose systemic steroids
Main differential for GCA?
Pain and raised ESR and CRP
Non-pulsatile tender temporal arteries
Scalp tenderness
Symptoms of GCA?
Sudden painful severe monocular vision loss (transient episodes before) can spread to other eye in hours
Headaches and scalp tenderness
Loss of appetite and weight loss
Signs of GCA:
Non-pulsatile tender temporal arteries
Swollen optic disc and RAPD
Flame haemorrhages and cotton wool spots indicating retinal nerve fibre layer infarction
What do flame haemorrhages and cotton wool spots indicate?
Retinal nerve fibre layer infarction
What is retinal migraine?
Vasospasm of the retinal artery causing occlusion
Central retinal artery occlusion causes?
Loss of central and peripheral vision
Cherry red spot at macula
RAPD
Branch retinal artery occlusion causes:
Result ranges from small asymptomatic peripheral scotoma to loss of VA if involves area supplying fovea
Can cause RAPD if large enough occlusion
Symptoms of retinal artery occlusion:
Sudden painless unilateral profound loss of vision
May be preceded by amaurosis fugax
What is amaurosis fugax?
Painless transient loss of vision
What do cotton wool spots indicate?
Infarcts of the nerve fibre layer
Result of retinal vein occlusion?
Retinal/macula oedema
Reduction in VA
CRVO = haemorrhage throughout the fundus
Retinal haemorrhage and cotton wool spots
Later features of retinal vein occlusion
Optic disc collateral vessels Pathological vessels grow from the optic disc into the vitreous cavity causing vitreous haemorrhage Rubeotic glaucoma (new vessels on iris block outflow)
Which test reveals macula oedema?
Optical coherence tomography
What use is a fluorescein angiogram in retinal vein occlusion?
View retinal/optic disc neovascularisation and macular oedema
Can classify disease as ischaemic or non-ischaemic
How to manage retinal vein occlusion:
Intravitreal steroid injections for macular oedema
Anti-VEGF drugs e.g. ranbizumab and aflibercept
Macular laser to leaking areas from BRVO
PRP laser ablates peripheral retina to reduce O2 demand and reduce VEGF (treats robotic glaucoma)
Risk factors for AACG:
Hypermetropia Narrow anterior chamber angle Age > 30 Asian/Inuit Women
Symptoms of AACG:
Unilateral red painful eye with vision loss. (6/36 or worse)
Halos around lights
N+V and headache
Can be asymp with previous intermittent symptoms
Signs of AACG:
Decreased VA Corneal oedema Raised IOP Oval, unreactive pupil Hypermetropia
Treatment of AACG to lower IOP:
Systemic: acetazolamib 500 mg IV stat
Eye drops: timolol 0.5%, apraclonidine 1%
Laser: YAG peripheral iridotomy (bypass pupil block)
Pathology of AACG:
Failure of aqueous humour to drain out through pupil and trab meshwork
e.g. due to pupil-block or iris being pushed forward onto trab meshwork
What are the two layers of the retina?
Neurosensory
Retinal pigment epithelium
What is a rhegma?
Retinal tear (caused by posterior vitreous detachment)
What is a rhegmatogenous retinal detachment?
Vitreous fluid passes through the tear, separating the two layers
Symptoms of retinal detachment?
Mainly loss in VF, if macula is lost then also a loss in VA
Floaters
Peripheral photophobia (flashing lights)
Exams with retinal detachment:
Dilate with phenylephrine 2.5% and tropiccamide 1% drops (avoid if previous AACG)
Measure VA and check for RAPD (present if big enough)
Check peripheries and other eye
Surgery for retinal detachment:
Cryobuckle surgery
Pars plana vitrectomy
(treat. before macula detaches
