Sudden loss of vision Flashcards
(37 cards)
What differentials should be considered in acute painless loss of vision?
-CRAO CRVO Branch artery occluion AION Vitreous haemorrhage retinal detachment
What is the pathogenesis of retinal vein occlusion?
Thrombosis, commonly at an AV cross. CLotting tendency can be increased in hyperviscosity states eg smoking, pill, pregnant
What is the clinical presentation of retinal vein occlusion?
middle aged/old pt
suddent painless loss of vision
may be a APD
haemorrhage, cotton wool, swollen disc and macular oedema. usually unilateral
What are the important complications of retinal vein occlusion?
macular oedema
neovascularistation of iris and retina
iris neovascularisation (rubeosis) can lead to severe, painful glaucoma which is difficult to control.
How should a patient be assessed with retinal vein occlusion?
Common systemic associations include hypertension and diabetes. Rarely, blood dyscrasias or vasculitis may be the cause. The major ocular association is elevated intraocular pressure. The diagnosis is clinical. Investigations are directed primarily at excluding treatable associations.
treatment of retinal vein occlusion?
Treatment is of the disease and of any systemic associations.
macular oedema-laser may help in branch
neo- laser (not proven)
pathogenesis of retinal artery occlusion?
Arterial occlusions typically lead to more severe visual loss than venous occlusions.
Commonest cause is embolisations, usually from carotids. inflammation may cause occlusion
associated with HTN, Diabetes, IHD, CAD
How does retinal artery occlusion present?
Branch- may not give symptoms
Central artery occlusions usually present with the sudden onset of severe monocular loss of vision, often to “counting fingers”or worse. The patient may report having experienced similar but transient episodes previously (amaurosis fugax).
Marked APD
key features of retinal artery occlusion?
History of amaurosis fugax
Retinal pallor,
cherry red spot (recedes after 6 weeks)
Narrow truncated arteries Emboli visible within arterioles
How should patients with retinal artery occlusion be assessed?
often have systemic conditions HTN, DM, IHD, PVD
can carotid doppler
What is the treatment for retinal artery occlusion?
Regular prophylactic aspirin is prescribed, if not contraindicated, since it is likely to have a protective effect against arterial occlusion in the other eye and against stroke.
clinical features of anterior ischaemic optic neuropathy (AION)?
Sudden onset sight loss, usually unilateral at first, may be preceded by transient episodes of visual loss. There is a relative afferent pupillary defect and a swollen optic disc, with haemorrhage and cotton wool spots
different types of AION?
arteritis and nonarteritic. The arteritic form is caused by giant cell (temporal) arteritis. Urgent diagnosis and treatment with systemic steroids is necessary to prevent bilateral blindness.
Nonarteritic ischaemic optic neuropathy has no sign of inflammation and is associated with atherosclerosis, hypertension, smoking and diabetes mellitus.
What is retinal detachment?
Retinal detachment is a cleavage in the plane between the neurosensory retina and the retinal pigment epithelium (the subretinal space). Most cases of retinal detachment are rhegmatogenous, cause by a tear or hole in the neurosensory retina, which allows fluid from the vitreous humour to pass through into the subretinal space.
2 main types of retinal detachment?
tractional, when the retina is pulled off by membranes growing across its surface (e.g. advanced diabetic eye disease) - exudative, caused by breakdown of the blood-retinal barrier allowing fluid to accumulate in the subretinal space (e.g. choroidal tumour, uveitis)
What clinical examination should be performed in cases of acute painless loss of vision?
Measure the visual acuity. Examine the pupils for RAPD. Examine the red reflex, which is reduced or absent in vitreous haemorrhage. Perform ophthalmoscopy. Look for evidence of: - diabetic retinopathy (retinal haemorrhages, hard exudates, and cotton wool spots) - retinal vein occlusion (retinal haemorrhages and cotton wool spots) - retinal artery occlusion (yellow refractile plaques of bifurcation of retinal arterioles, cherry red spots on the macula, optic disc swelling) - Wet ARMD (macular haemorrhages and hard exudates) - Examine the cardiovascular system
What investigations are useful in cases of acute painless loss of vision?
In the case of ischaemic optic neuropathy or retinal artery occlusion, an ESR, plasma viscosity and/or CRP should be done to exclude giant cell arteritis. The blood sugar and lipid profile need to be measured. Do an FBC to check for thrombocytopaenia. Carotid Doppler ultrasound should be requested to determine the extent of carotid artery stenosis.
I have flashing lights and floaters in one eye” What is the differential diagnosis?
“I have flashing lights and floaters in one eye” What is the differential diagnosis? Posterior vitreous detachment (PVD) Retinal detachment Migraine Vitreous haemorrhage Other visual phenomena - retinal or cerebral underperfusion - look for features of arteriopathy Posterior segment inflammation (posterior uveitis)
What is posterior vitreous detachment?
. Posterior vitreous detachment is the most common cause of acute onset floaters, particularly with advancing age and is one of the most common causes of acute visual disturbance.
How is vitreous detachment managed?
Patients with an acute posterior vitreous detachment should have urgent ophthalmic referral, so that any retinal breaks or detachments can be treated at an early stage.
How does vitreous haemorrhage present?
Large bleeds cause sudden visual loss. Moderate bleeds may be described as numerous dark spots. Small bleeds may cause floaters. Flashing lights indicates radial traction and is a bad sign. Causes include diabetes and bleeding disorders. The red reflex may be reduced.
How is vitreous haemorrhage managed?
The patient should be referred to an ophthalmologist to exclude retinal detachment. Ultrasound examination of the eye may be useful, particularly if the haemorrhage occludes the view of the retina. If it fails to clear spontaneously, the patient may need the vitreous removing (vitrectomy).
What causes optic neuritis
This is another cause of acute visual disturbance. Causes include: - MS - Syphilis - Diabetes
What are the clinical features of optic neuritis?
unilateral decrease in visual acuity over hours or days. There is poor discrimination of colours with “red desaturation” and pain is also worse on eye movement. There is also relative afferent pupillary defect.
