Diabetic retinopathy refers to disease of the retinal vessels which is as a result of diabetes. It can happen in the case of Type 1 or Type 2 diabetes, however it is more common in older patients who have Type 2.
While diabetic retinopathy can be treated in its advanced stages, the consequences to vision can be dramatic. Maintaining good control of blood glucose levels is the best way to delay or prevent the onset of late stage retinopathy.
Diabetic eye disease as it appears on a digital retinal photograph. Notice the large haemorrhage, resulting from breakdown of weakened blood vessel walls. Some of he pale patches are referred to as "cotton wool spots", and are a result of damage to nerve fibres in the retina. Other are lipid deposits that result from the damaged blood vessels.
Diabetic Retinopathy involves damage to the retina in association with the complications of Diabetes. The small blood vessels of the retina are damaged in this condition, which leads to a series of severe visual disturbances and even blindness.
In the early stages of the disease, tiny retinal blood vessels begin to swell and burst like balloons (microaneurysms). Following this, blood vessels that nourish the retina progressively begin to close. This inhibits the retina from receiving essential blood supply and therefore, the retina begins to send signals to grow new blood vessels for nourishment.
In the advanced stage of the disease, the signals sent by the retina begin the growth of new blood vessels. These new blood vessels are abnormal and fragile and are prone to leaking. If a blood vessel leaks, severe vision loss and even blindness can occur.
The vision loss in Diabetic retinopathy is caused by 2 processes:
1. Proliferative Retinopathy
As mentioned above, where leaking of blood causes blurring of vision.
2. Macular Oedema
Here, fluid leaks from blood vessels into the macula causing the macula to swell, blurring vision. This generally occurs as the disease progresses. About half of the people with proliferative retinopathy also have macular oedema.