The most common cause of diabetes-related blindness is "Diabetic Retinopathy".

Diabetes is a metabolic disease characterized by elevated blood glucose as a result of insufficient release or action of insulin.

Diabetes particularly affects the eye's neural layer (retina) and the capillary vessels in this layer, disrupting their function and leading to loss of vision. Retinal disorders associated with diabetes are called diabetic retinopathy.

In diabetic patients, an eye examination should be performed from adolescence on in young people and at the time of diagnosis in individuals that develop diabetes after 30 years of age. If their retina is normal, an annual eye examination should be performed in diabetic patients. Once a retinopathy starts, the interval of check-ups can be reduced to 3-4 months.

Causes of Diabetic Retinopathy

The primary risk factor for diabetic retinopathy is the duration of diabetes. The incidence of retinopathy increases particularly after the 10th year following the diagnosis of diabetes. In young patients with type 1 or insulin-dependent diabetes, the incidence of retinopathy increases with age after adolescence.

Keeping blood glucose under control is an important factor. Unstable blood glucose levels and sudden increases and decreases in blood glucose make retinal deterioration and disease progress easier. Pregnancy, hypertension, elevated blood fats (hyperlipidemia) and kidney disease are factors aggravating retinopathy.

Diabetes damages retinal capillary vessels, causes cell loss, disrupts vessel permeability and causes retention of fluid and fatty substances in the macular area, hence obstruction of capillaries, leading to areas with no blood supply. New vessels are formed in the retina which can bleed spontaneously. Bleeding occurring in front of and inside the retina may leak into the eye's posterior chamber. Venous membranes are formed in the retina, leading to serious losses of vision and painful elevations in eye tension.