Diabetes is a major cause of disease in the retina. The retina is the back part of the eye where light is focused and processed, with messages ultimately being sent to the brain. All the receptors that sense light are in the retina. Its not surprising that when significant disease affects this part of the eye, the individual goes blind.
Diabetes is the major cause of blindness in "working-aged" Americans. Diabetics can lose their sight at a young age and this loss is permanent.
One problem is an overgrowth of blood vessels in the eye, but these vessels are very abnormal, and very fragile. They are likely to bleed suddenly. This blood by itself takes away vision by blocking the passage of light through the eye. Worse still, the bleeding produces scars that can damage the actual retina. This type of blindness is irreversible.
Diabetic eye disease can be prevented. Better glucose control markedly lowers the risk of eye disease. Excellent blood pressure control is also essential. Surprisingly or perhaps not smoking increases this risk as well, yet another reason why diabetics must not smoke.
Those with Type 2 diabetes should see their eye specialist once a year, once they have been diagnosed with the disease. With Type 1 diabetes, the patient should see his or her eye specialist within five years of the diagnosis, and every year thereafter. Exceptions to these rules include patients who are going through puberty and pregnant women. In these cases, ask your doctor or educator for recommendations. The specialist can spot retinopathy early in its course and track it, treating when necessary. Current treatment involves laser therapy to the affected eye. This treatment prevents blindness in the vast majority of people at risk, although the way it works is not yet clearly understood.