Retinopathy

Diabetes mellitus, a condition where the blood sugar concentration is persistently elevated, is a major health affliction in our population. A recent national health survey estimated that 9% of our population, or about 1.9 million Malaysians, suffer from this malady. Generally, diabetes mellitus (DM) can be divided into two main types. Type 1 DM refers to the disease in which the age of onset is 30 years or younger, whereas Type 2 DM refers to adult onset disease, usually above the age of 30 years. By far, the most common type of DM is the Type 2 DM, accounting for more than 95% of all diabetic patients.

Of the many body system that can be affected by uncontrolled diabetes, the eye is an important organ that often takes the brunt of the disease, and literally, with ‘visible’ effect. Essentially, the structure and the function of the blood vessels in the diabetic person are altered, making the blood vessel walls prone to hardening, narrowing, leaky and eventually, poor blood flow. Such changes when occur in the eye, usually affects the light-sensing layer at the rear of the eye.

This layer, the retina, is analogous to the film in the camera. For the eye to see well, the retina must be of good health. However, in the early stages of the abnormal changes in the retina, or diabetic retinopathy, the patient may not notice any symptoms. With progression of retinopathy, the patient will experience blurriness in vision. This blurriness is usually caused by fluid and fats leakages from abnormal blood vessels in the retina layer, making the nerve layer swollen.

With deterioration in retinopathy, the altered blood vessels may soon be blocked, and the retina will be starved of oxygen and nutrients that are normally delivered with the blood flow. The vision may decrease further and often abnormal growth of ‘new’ vessels on the retina will ensue. These new vessels formation is the result of an attempted compensatory mechanism by the eye in response to the oxygen-starvation state. These ‘new’ vessels bring about devastating results as they are highly fragile and often grow hand-in-hand with abnormal scar tissues on the retina surface.

The fragile, abnormal ‘new’ vessels can cause massive sudden bleeding inside the eye, obscuring vision. In addition, the scar tissues on the retina surface often contracts, the effect of which crumple and distort the retina layer. Moreover, the pull by these contracting scars on the retina detaches the retina from its usual place, i.e., lining the rear part of the eye, This leads to further permanent damage to the eye and vision.

There had been highly effective treatment for retinopathy, primarily the use of laser, for some 20 years now. Prior to the introduction of laser in treatment of diabetes retinopathy, about 10% of patients with severe retinopathy will go blind with each passing year. With appropriate and timely laser treatment, the risk of blindness is reduced by more than 95%. The aim of the laser treatment is the prevention of deterioration in retinopathy. Appropriate laser treatment works by preventing the growth of abnormal ‘new’ vessels and the scar tissues, and minimizes their attendant catastrophic visual effects in the diabetic eye. Therefore, it is important for the patient to realize that laser treatment in diabetes is not meant to improve but to maintain vision, and the reason behind the recommendation for treatment by their eye doctors even though the patient may not had experienced any visual disturbances yet.

In more severe cases, where abnormal blood vessels and scar tissues had resulted in serious retinal damage, laser treatment alone is no longer effective in restoring sight. The patient will require retinal surgery to remove the abnormal vessels, blood, and scar tissues on the retina in order to salvage vision and the eye. Although such sophisticated surgery is technically challenging, it is currently available and offered by selected retinal surgeons in our country.