Diabetic Retinopathy Flashcards
what are risk factors for diabetic retinopathy
Long duration of illness Pregnancy Poor control HTN Renal disease Obesity Smoking
what is the pathology of diabetic retinopathy
Hypoxia/Hyperglycaemia associated with diabetes causes pericyte loss in the capillary wall, causing microaneurysms in the venous system. this encourages leakage and odema which causes a chronic ischaemia in a highly metabolic region, leading to shunt vessel formation (not new vessels yet) but these tend to be insufficient so VEGF and other angiogenic factors are released causing new vessel formation
how do hard exudates form
consequences of chronic retinal odema, causing impaired function, this promotes macrophages to engulf and clear up the odema, the waste product of this being the fatty lipid deposits of hard exudates
how is diabetic retinopathy classified
background retinopathy
pre-proliferative retinopathy
proliferative retinopathy
What is a maculopathy
microaneurysms in macula causing pathology, may be present in any of the retinopathy classifications
what are features of background diabetic retinopathy
microaneurysms
haemorrhages - dot, blot and flame
exudates
normal vision
what are features of pre-proliferative diabetic retinopathy
cotton wool spots - focal axonal infarction
venous shunt formation
dark blot haemorrhages
intraretinal microvascular abnormalities (IRMA)
what are intraretinal microvascular abnormalities
vein changes
beading
looping
what are features of proliferative abnormalities
Neovacularisation (of disc, retina, may be flat or elevated, severity done by comparing area of disk)
Haemorrhage - vitreous in older patients
Vision normal until haemorrhage
why do vitreous hemorrhages only occur in the older populations
older peoples vitreous liquid whereas its solid in young people
how do you treat diabetic retinopathy
Laser panretinal photocoagulation
vitrectomy
when is a vitrectomy indicated for diabetic retinopathy
if neovascularisation and haemorrhage is present after laser treatment
why may haemorrhage still occur after laser treatment
VEGF release from the vitreous
what are features of panretinal photocoagulation
2000-3000 burns into the retina, leaves macula alone so most sensitive aspects of vision are ok
kills new vessels to save vessels in macula which are the most essential
retina split into a 3 layer bullseye with macula in the middle, outside ring (c-zone) done first if regression is seen no more is done, the inside (Bzone) has a single impact on visual fields
what are features of focal diabetic maculopathy
causes circumscribed retinal thickening and complete/imcomplete hard exudate
treated with focal laser treatment
