Diabetic eye disease/ retinopathy Flashcards
Define microvascular complications and give examples
Complications of smaller vessels
e.g:
Retinopathy
Nephropathy
Neuropathy
What is the relationship b/t glucose levels and microvascular complications?
- Extent of hyperglycaemia (as judged by HbA1c) is strongly associated with the risk of developing microvascular complications
What is the relationship b/t systolic bp and microvascular complication?
- Clear relationship between rising systolic BP (hypertension) and risk of MI and microvascular complications in people with T1DM and T2DM
- Therefore, prevention of complications requires reduction in HbA1c and BP control
(not just management of sugars- need to check BP, cholesterol, etc)
Describe the pathophysiology of diabetic retinopathy
Chronic hyperglycaemia in diabetes mellitus causes structural changes to the retinal capillaries, including thickening of the basement membrane and loss of pericytes. This results in capillary occlusion and leakage, leading to retinal ischaemia and formation of new, fragile vessels.
What is diabetic retinopathy?
- Over time, too much sugar in your blood can lead to the blockage of the tiny blood vessels that nourish the retina
- cutting off its blood supply
- As a result, the eye attempts to grow new blood vessels
- But these new blood vessels don’t develop properly and can leak easily.
What would you find on a normal retina scan?
- Optic disc (bright white spot) the area where specific nerve fibres exit the retina to form the optic nerve
- Macula (slightly pink- found centrally) the part responsible for central and fine-detail vision, high resolution and colour vision needed for tasks such as reading.
What is background retinopathy? What would you see on an OCT?
- Earliest stage of retinopathy (no new blood vessels formed yet)
- The walls of the blood vessels in your retina weaken
- Tiny bulges protrude from the walls of the smaller vessels, sometimes leaking fluid and slight blood into the retina
- don’t usually affect your vision – this is known as background retinopathy
OCT: - Hard exudates (yellow bright spots with well defined edges= lipid residues that leak from the impaired blood–retinal barrier)
- Microaneurysms (dots)
- Blot haemorrhages (red dots)
What is Pre-proliferative retinopathy? What would you see on an OCT?
- 2nd stage- after background retinopathy (but NO new blood vessels formed yet)
- More severe and widespread changes affect the blood vessels (more vessels blocked)
- More significant bleeding into the eye – this is known as pre-proliferative retinopathy
OCT: - Soft exudates (Cotton wool spots- more places with ill- defined edges: hard exudate spots represent leakage, wheras soft exudates represent ischemia and are more serious)
- Haemorrhage
What is proliferative retinopathy?
- Last stage of retinopathy (new blood vessels form)
- Damaged blood vessels close off
- Causing the growth of new, abnormal blood vessels in the retina (esp around the optic disc)
- These new blood vessels are fragile and can leak
- Increases the risk of haemorrhage
- This is known as proliferative retinopathy and it can result in some loss of vision
What is Maculopathy? What would you see on an OCT?
- Maculopathy occurs when the leaked fluid builds up at the macula,
- leaking into the retina causing swelling
- Occasionally, the blood vessels in the macula become so constricted that the macula is starved of oxygen and nutrition causing your sight to get worse
OCT:
*Hard exudates/ oedema near the macula - Cotton wool spots (soft exudates)
How would you treat Background retinopathy?
General retinopathy treated with:
- Improve HbA1c
- stop smoking
- lipid lowering
- good blood pressure control <130/80 mmHg
BR specifically:
Continued annual surveillance
How would you treat pre-proliferative retinopathy?
General retinopathy treated with:
- Improve HbA1c
- stop smoking
- lipid lowering
- good blood pressure control <130/80 mmHg
PPR specifically:
(If left alone will progress to new vessel growth) so, early panretinal laser photocoagulation
What is panretinal photocoagulation?
Thermal burns in the peripheral retina leading to tissue coagulation, the overall consequence of which is improved retinal oxygenation
- prevents formation of new blood vessels BUT can cause peripheral vision damage
How would you treat Proliferative retinopathy?
General retinopathy treated with:
- Improve HbA1c
- stop smoking
- lipid lowering
- good blood pressure control <130/80 mmHg
PR specifically:
Panretinal laser photocoagulation
How would you treat diabetic maculopathy?
General retinopathy treated with:
- Improve HbA1c
- stop smoking
- lipid lowering
- good blood pressure control <130/80 mmHg
Maculopathy specifically:
- Oedema: Anti-VEGF injections directly into the eye (VEGF: vascular endothelial growth factor)
- Grid photocoagulation
