Diabetic eye disease Flashcards
How does diabetes affect the eyes?
Because chronic hyperglycemia can have ravaging effects on blood vessels, many people with diabetes—especially those who depend on insulin injections to control blood sugar—eventually develop vascular problems in the eye. The most common diabetic eye disease is retinopathy, which involves abnormal swelling, permeability, or growth of the retinal blood vessels. The leakage of fluid from the retinal vessels may cause edema of the macula, which is responsible for central vision—thus leading to vision loss.
What is diabetic retinopathy?
characterised by damage to the microvasculature supplying the eye due to chronically high glucose levels. The resulting insult to retinal cells can lead to a progressive deterioration in vision through various mechanisms and can lead to blindness.
What is the aetiology behind diabetic eye disease?
Chronic hyperglycaemia causes blood vessels, including those supplying the retina, to weaken and rupture; the vessel walls may dilate resulting in microaneurysms or small haemorrhages.
The damaged pericytes and erythrocytes increase vascular permeability. Lipoproteins, lipids and other products carried by blood are therefore able to leak out and cluster onto the retina as hard exudates.
As blood flow becomes increasingly compromised, regions of the retina are starved of oxygen. This hypoxia is thought to stimulate the release of mediators such as vascular endothelial growth factor (VEGF) which promotes neovascularization. However, these new vessels are poorly formed and easily rupture resulting in bleeding.
Neovascularization into the vitreous humour may culminate in widespread vitreous haemorrhage causing sudden and complete visual loss. Fibrovascular bundles can lead to fibrosis and, in turn, retinal traction. This can result in retinal detachment and recurrent vitreous haemorrhage
What are the risk factors for diabetic retinopathy?
- Length of exposure to hyperglycaemia
- Duration since diabetes diagnosis
- Hypertension
- Ethnicity (minority groups)
- Pregnancy
- Rapid improvement of blood sugar levels
- Hyperlipidaemia/ hypercholesterolaemia
How do hard exudates appear on fundoscopy?
yellow-white deposits of lipids and protein on the retina
How do microaneurysms appear on fundoscopy?
small dark dots
What causes the formation of cotton wall spots in diabetic retinopathy?
damage to nerve fibres
Give 4 fundoscopy signs seen in background diabetic retinopathy:
1) microaneurysms
2) retinal haemorrhages
3) hard exudates
4) cotton wool spots
Give 2 fundoscopy signs seen in pre-proliferative diabetic retinopathy:
1) venous bleeding
2) multiple blot haemorrhages
Give 2 fundoscopy signs seen in proliferative diabetic retinopathy:
1) neovascularisation
2) vitreous haemorrhage (bleeding into vitreous humour)
Give 6 complications of diabetic retinopathy:
1) vision loss
2) retinal detachment
3) rubeosis iridis (new vessels forming in iris)
4) cataracts
5) optic neuropathy
6) vitreous haemorrhage
How is non-proliferative diabetic retinopathy managed?
close monitoring and diabetic control
Give 3 options for proliferative diabetic retinopathy management:
1) pan-retinal photocoagulation (laser treatment to prevent formation of new vessels)
2) anti-VEGF medications (e.g. Avastin)
3) vitrectomy
What typical symptoms will patients with diabetic retinopathy present with?
- Floaters
- Blurred vision
- Decreased visual acuity
- Loss of vision
- Blindness
What can non-proliferative diabetic retinopathy be divided into?
- Background retinopathy
- pre-proliferative retinopathy
