The Eye in Diabetes

Dr Sarita Bajaj,
DM(Endocrinology, AIIMS),
Associate Prof Medicine,
MLN Medical College, Allahabad.

Long standing diabetes can affect the heart, the kidneys, the peripheral nerves, the foot and the eyes.

Premature cataract (lens opacification) is the commonest ocular complication of diabetes. The other important sight threatening complication of diabetes is diabetic retinopathy (DR). The prevalence of DR is directly related to the duration of diabetes. After 25 to 30 years of disease about 90% of patients develop mild DR. Severe DR occurs in 10% of patients who are insulin dependent, within 15 years and more than 25% after 20-50 years. Blindness occurs in 45% of insulin dependent diabetics and 60% of non insulin dependent diabetics within 5 years of development of severe DR.

Diabetic Retinopathy is the term applied to specific changes in the Retina (the curtain behind the eye on which light rays fall) which can occur in people with diabetes. The changes involve the small blood vessels of the retina.

An eye with marked changes of DR can have good vision and be totally symptomless. Seeing black spots, floating objects of various shapes and sizes and cob-webs are usually symptoms which point to a bleed inside the eye. A reduction in vision may occur if the macula (area responsible for central vision) is affected by oedema (swelling). Only an examination of the retina by the eye specialist will help clarify the situation.

Strict control of diabetes will delay the onset and control progress of DR. If the initial control has been poor and eye complications have started, they can not be reversed even if blood sugar is brought to normal.

Since in the early stages DR may be symptomless it is importance to have a regular eye check up

Detailed eye examination (fundus examination) is essential.

1. On detection of diabetes

2. Once every year (if duration of diabetes is < 10 years)

3. Once every 6 month (if duration of diabetes is > 10 years)

4. In DR once in 3-6 months (as advised by the eye specialist)

Laser (photocoagulation) treatment is done for DR. In suitably chosen cases it can prevent visual loss in eyes which run such a risk.

Specialised surgical procedures like vitrectony may be necessary is advanced diabetic eye disease. Till today there is no specific medication than can cure or prevent DR.

Periodic follow up is essential in patients with no or mild retinopathy. However there are a group of patients who have very advanced disease whom neither photocoagulation nor vitrectomy can help.