The eye in systemic disease Flashcards
What is the difference between proliferative and non-proliferative diabetic retinopathy?
In proliferative diabetic retinopathy there is formation of new vessels - neovascularisation
What is the pathogenesis of diabetic retinopathy?
Microaneurysms cause haemorrages and ischaemia in the eye - chronic hyperglycaemia has caused glycosylation of the basement membrane and loss of pericytes
What are pericytes?
Contractile cells that wrap around endothelial cells of capillaries and venules
What are dot blot haemorrages?
A sign on physical examination that shows a haemorrage within the retina - the blood has become trapped, causing the ‘dot/blot’ marking
What are intraretinal microvascular abnormalities?
Abnormalities of the blood supply of the retina that indicate diabetic retinopathy
What are the signs of non-proliferative diabetic retinopathy?
Microaneurysms / dot + blot haemorrhages
Hard exudate
Cotton wool patches
Abnormalities of venous calibre
Intra-retinal microvascular abnormailities (IRMA)
Where can new vessels in proliferative diabetic retinopathy grow?
On the disc
In the periphery
On iris if ischaemia is severe
What do diabetic patients lose vision from?
Retinal oedema affecting the fovea
Vitreous haemorrhage
Scarring/ tractional retinal detachment
What is diabetic macular oedema?
When the blood vessels of the macula leak fluid or protein onto the macula
When does macular oedema become clinically significant?
If the retina hardens and exudates become increasingly large and close to the fovea
How is diabetic retinopathy treated?
Rehabilitation for blind/partially sighted
Laser for proliferative neovascularisation and on macular grid
Surgery - vitrectomy
What is the pathogenesis of hypertensive retinopathy?
Arterioles respond to hypertension by vascoconstricting to reduce flow
Chronically, causes endothelial damage because of high pressure
There are breaks in the wall of the arterioles due to this damage, leaking plasma into the vessel wall and causing clotting
This causes mural thickening and luminal narrowing, called fibrinous necrosis
What are the signs of hypertensive retinopathy?
Attenuated blood vessels-copper or silver wiring
Cotton wool spots
Hard exudates
Retinal haemorrhage
Optic disc oedema
How might central retinal artery occlusion present?
Sudden, profound visual loss
How can degree of ischaemia in central retinal artery occlusion be determined?
Correlates directly to the degree of visual loss and fundal appearance
