Diabetes eye disease Flashcards
(22 cards)
How many years after developing diabetes does diabetic retinopathy typically occur.
Diabetic retinopathy (DR) is a complication of diabetes, resulting from damage to the small blood vessels, generally occurring 10 years after diabetes onset (which may be some years before the diagnosis of type 2 diabetes).
What are the 3 classifications of diabetic retinopathy?
Background
Pre-proliferative
Proliferative
What are the 4 characteristic features of background retinopathy?
- Microaneurysms.
- Haemorrhages—dot and flame-shaped.
- Hard exudates.
- Soft exudates/cotton wool spots.
What are the 4 characteristic features of pre-proliferative retinopathy?
- Multiple blot haemorrhages.
- Intraretinal microvascular abnormalities (IRMAs).
- Venous beading.
- Venous reduplication
What are the 5 characteristic features of proliferative retinopathy?
- New vessels on the disc (NVD) or within 1 disc diameter of it.
- New vessels elsewhere (NVE).
- Fibrovascular proliferation ± tractional retinal detachment.
- Pre-retinal or vitreous haemorrhage.
- Rubeosis iridis (± neovascular glaucoma).
What are the 4 diagnostic criteria for maculopathy?
- Exudate within 1 disc diameter (DD) of the centre of the fovea.
- Group of exudates within the macula.
- Any microaneurysm or haemorrhage within 1 DD of the centre of the fovea only if associated with a best VA of ≤6/12 (if no stereo).
- Retinal thickening within 1 DD of the centre of the fovea (if stereo available).
What is the pathophysiology of diabetic retinopathy?
One of the first histological changes seen is thickening of the basement membrane and loss of pericytes embedded within it, forming acellular capillaries. Breakdown in endothelial cell tight junctions leads to increased capillary permeability. The microaneurysm is the hallmark of retinal microvascular disease in diabetes. Microaneurysms may be asymmetrical dilatations of the capillary wall where it is weakened or damaged, following the loss of the supporting pericytes and localized increases in hydrostatic pressure. Smooth muscle cell death, capillary weakening and closure, with the occurrence of intraretinal microvascular abnormalities (IRMA), and impaired autoregulation are all features of diabetic retinopathy.
What actually is a cotton wool spot?
A cotton wool spot is a delay in transmission along the axoplasm of the nerve fibre layer of the retina, caused by ischaemia.
What are Intraretinal microvascular abnormalities (IRMAs)? From what do they derive?
Intraretinal microvascular abnormalities (IRMA) are tortuous intraretinal vascular segments varying in calibre. They derive from remodelling of the retinal capillaries and small collateral vessels in areas of microvascular occlusion.
In proliferative retinopathy there is neovascularisation in the retina. This can be categorised in one of two ways, what are these?
New vessels developing in diabetic retinopathy are characterized according to whether they develop at or near the optic disc (NVD) or elsewhere in the retina (NVE). They usually develop from the venous circulation and grow forwards in the vitreous gel, but they can also develop from the arterial circulation.
New vessels on the disc (NVD) are defined as any new vessel developing at the optic disc or within 1 disc diameter of the edge of the optic disc.
New vessels elsewhere (NVE) are defined as any new vessel developing more than 1 disc diameter away from the edge of the optic disc.
What are the symptoms of proliferative retinopathy? What are the 4 main complications of proliferative retinopathy?
Both give no symptoms but cause the problems of advanced retinopathy, such as haemorrhage, scar tissue formation, traction on the retina, and retinal detachment which actually results in loss of vision.
What is the management of low-risk and high-risk proliferative retinopathy?
The Diabetic Retinopathy Study (DRS) recommended prompt treatment with panretinal photocoagulation in the presence of DRS high-risk characteristics.
Because the side effects of modern laser treatment are considerably less than the early lasers, most ophthalmologists treat eyes that develop new vessels of either the high- or low-risk categories.
What are the 3 classifications of diabetic macular oedema?
Diabetic macular oedema or maculopathy may be classified into focal, diffuse, and ischaemic types.
What are the defining features of focal diabetic macular oedema?
In focal maculopathy, focal leakage tends to occur from microaneurysms, often with a circinate pattern of exudates around the focal leakage.
What are the defining features of diffuse diabetic macular oedema?
In the diffuse variety, there is a generalized breakdown of the blood–retina barrier and profuse early leakage from the entire capillary bed of the posterior pole, sometimes accompanied by cystoid macular changes.
What are the defining features of ischaemic diabetic macular oedema?
In ischaemic maculopathy, enlargement of the foveal avascular zone (FAZ) due to capillary closure is found with variable degrees of visual loss.
What is the current diabetic retinopathy screening programme in England?
In England, the method used is two-field mydriatic digital photography, with screening performed by technician screeners or optometrists. Fixed locations and mobile units are both used.
Give 3 criteria for immediate referral to an ophthalmologist.
- Rubeosis iridis/neovascular glaucoma.
- Vitreous haemorrhage.
- Advanced retinopathy with retinal detachment.
Give the 1 criteria for urgent referral to an ophthalmologist.
Proliferative retinopathy
Give 4 modifiable risk factors for development of diabetic retinopathy.
- Glucose control.
- Systemic hypertension.
- Blood lipids.
- Smoking in type 1 diabetes.
Give 5 non-modifiable risk factors for development of diabetic retinopathy?
- Duration of diabetes.
- Age.
- Genetic predisposition.
- Ethnicity.
- Pregnancy.
What is the alternative medical therapy to surgery? Give the name of 3 of the medications.
Ocular neovascularization (angiogenesis) and increased vascular permeability have been associated with Vascular Endothelial Growth Factor (VEGF), which does also have a neuroprotective effect.
There are three potential VEGF inhibitors: pegaptanib, ranibizumab, and bevacizumab. Ranibizumab is an antibody fragment derived from bevacizumab, which is a full-length humanized monoclonal antibody against human VEGF.
