Diabetic Retinopathy Flashcards
What is diabetic retinopathy?
The retinal consequence of chronic progressive diabetic microvascular leakage and occlusion. It eventually occurs to some degree in all patients with diabetes mellitus.
There are two types: non-proliferative and proliferative.
What’s the difference between non-prolierative and proliferative retinopathy?
Non-proliferative diabetic retinopathy (NPDR) is the early stage of the disease and is less severe. Blood vessels in the eye may leak fluid into the retina, which leads to blurred vision.
Proliferative diabetic retinopathy (PDR) is the more advanced form of the disease. New blood vessels start to grow in the eye (neovascularisation), which are fragile and can haemorrhage. This may cause vision loss and scarring of the retina.
What are the risk factors associated with diabetic retinopathy?
- Young-onset of diabetes
- Longer duration of diabetes
- Poor glycaemic control
- Hypertension
- Renal disease
What are the signs of diabetic retinopathy?
- Microaneurysms
- Cotton wool spots
- Intraretinal haemorrhage
- Lipid exudate
- Floaters
What are the symptoms of diabetic retinopathy?
- Vision loss
What investigations should be ordered for diabetic retinopathy?
- Photographs of the fundus
- Optical coherence tomography scanning
- Fluorescein angiography
- B scan ultrasonography
Why investigate using photographs of the fundus? And what may this show?
- Should be ordered at baseline evaluation and when significant change is perceived in the fundus findings
- Change from the first photograph
Why investigate using optical coherence tomography scanning? And what may this show?
- Should be ordered if there is any evidence of diabetic retinopathy affecting the posterior pole, or unexplained visual loss
- The scan may demonstrate macular oedema
Why investigate using fluorescein angiography? And what may this show?
- Should be ordered in patients with diabetic maculopathy to determine the source of leakage, to direct laser, to quantify macular ischaemia, and to evaluate the adequacy of intravitreal or macular laser therapy
- Identifies macular leakage, capillary non-perfusion and new vessels
Why investigate using B scan ultrasonography? And what may this show?
- Should be ordered when vitreous haemorrhage or other media opacity prevents visualisation of the fundus
- Identifies retinal detachment in eyes with vitreous haemorrhage
Briefly describe the treatment for diabetic retinopathy
- The main goals of therapy are to improve hypertensive and glycaemic control and ensure that sight-threatening disease is arrested before visual loss occurs, as visual loss is easier to prevent than to reverse.
- Although control of blood glucose and blood pressure slows the onset and delays the progression of retinopathy, once sight-threatening disease is present, ophthalmic treatment is necessary. Typically, this includes:
- Macular laser therapy
- Intravitreal therapy
- Pan-retinal photocoagulation
- Vitrectomy surgery
What are the complications of diabetic retinopathy?
- Cataracts
- Post-vitrectomy cataract
- Post-vitrectomy haemorrhage
- Para-central visual loss post-macular laser therapy
What differentials should be considered for diabetic retinopathy?
- Ocular ischemic syndrome
- Hypertension
- Retinal venous occlusion
How does diabetic retinopathy and ocular ischemic syndrome differ?
- Differentiating signs and symptoms: commonly presents with amaurosis fugax and gradual or sudden visual loss
- Differentiating investigations:
- Fluorescein angiography shows delayed arterial filling in affected eyes
- Doppler imaging may show carotid stenosis and ophthalmic artery flow reversal
How does diabetic retinopathy and hypetension differ?
- Differentiating signs and symptoms: systolic and diastolic pressures are markedly elevated. Associated with acute visual disturbance, with optic disc swelling (which is uncommon in diabetic retinopathy) and macular oedema often in the form of a macular exudate star.
- Differentiating investigations: fluorescein angiography reveals arteriolar non-perfusion, rather than capillary non-perfusion as in diabetic retinopathy.
