Sudden vision loss Flashcards
What are some causes of sudden vision loss?
Retinal artery/vein occlusion
Wet ARMD
Vitreous haemorrhage
Retinal detachment
Closed-angle glaucoma
*Sympathetic ophthalmia
Think ABC:
A - Age-related macular degeneration
B - Bleed or Blockage
C - Closed-angle glaucoma
What is the main artery that supplies the eye?
Ophthalmic artery
What branch of the ophthalmic artery supplies the inner 2/3rds of the retina?
Central retinal artery
What branch of the ophthalmic artery supplies the outer 1/3rd of the retina?
Posterior ciliary arteries
What are the 3 main forms of retinal artery occlusion?
- Central retinal artery occlusions (CRAO)
- Branch retinal artery occlusion
- Amaurosis fugax
What is a central retinal artery occlusion?
Occlusion of the central retinal artery, with resultant infarction of the inner 2/3 of the retina (outer 1/3 is supplied by choroid) and vision loss
What usually causes central retinal artery occlusion?
Arteriosclerosis-related thrombosis
Giant cel arteritis
What are some risk factors for developing central retinal artery occlusion?
- Older age
- Hypertension
- Diabetes
- Smoking
- Obesity
What are some symptoms of central retinal artery occlusion?
- Sudden, profound vision loss
- Painless
What is a sign of central retinal artery occlusion?
RAPD (Relative afferent pupil defect)
What will fundoscopy show in central retinal artery occlusion?
- Pale oedematous retina
- Thread-like retinal vessels
- Cherry red spot
What causes the cherry red spot on fundoscopy in central retinal artery occlusion?
Nerve fibre layer becomes opaque due to oedema, however, no nerve fibre layer at the fovea means that its normal reddish colour is seen against the retinal pallor
What is shown?
Central retinal artery occlusion
How should central retinal artery occlusion be managed?
Immediate referral to stroke clinic
What is a branch retinal artery occlusion?
Occlusion of one of the branches of the central retinal artery
How will branch retinal artery occlusion present?
- Acute onset of painless, monocular visual impairment
- The severity of visual loss depends upon the area of retinal tissue affected by the vascular occlusion
What will fundoscopy show in branch retinal artery occlusion?
Absence of perfusion in the affected artery
What is shown?
Branch retinal artery occlusion
How is branch retinal artery occlusion managed?
Refer to stroke clinic
What is amaurosis fugax?
Transient central retinal artery occlusion
What are some symptoms of amaurosis fugax?
- Transient painless visual loss
- Like a curtain coming down
- Lasts around 5 minutes and then recovers
How will amaurosis fugax show on fundoscopy?
Usually no signs of abnormality
How is amaurosis fugax managed?
Refer to stroke clinic
What are the 2 main types of retinal vein occlusion?
Central
Branch
How does central retinal vein occlusion occur?
Occurs when a thrombus forms in the retinal veins and blocks the drainage of blood from the retina
How does branch retinal vein occlusion occur?
Venous occlusion at any branch of the central retinal vein resulting in visual problems in the area drained by that branch
How does occlusion of a retinal vein cause problems?
- Blockage of a retinal vein causes pooling of blood in the retina, resulting in leakage of fluid and blood causing macular oedema and retinal haemorrhages
- This results in damage to the tissue in the retina and loss of vision
- It also leads to the release of VEGF, which stimulates the development of new blood vessels (neovascularisation)
How does retinal vein occlusion present?
- Sudden painless loss of vision
- Branch retinal vein occlusion may result in visual field defects corresponding to affected branch
What will be shown on fundoscopy in retinal vein occlusion?
- Flame and blot haemorrhages
- Optic disc oedema
- Macula oedema
- Dilated tortuous veins
What is shown?
Central retinal vein occlusion
How is central retinal vein occlusion managed in secondary care?
Treat macular oedema and prevent complications such as neovascularisation - laser photocoagulation, intravitreal steroids, anti-VEGF
What is sympathetic ophthalmia?
A condition in which injury to 1 eye causes vision loss in both eyes (Louis Braille had this)
How does sympathetic ophthalmia occur?
- Injury causes immune blood cells moving into the eye and recognise this as a foreign body as they are usually not in the eye (Due to blood-ocular barrier)
- This causes release of antibodies against both eyes
