Diabetes: Leading Cause Of Acquired Blindness In Adults
Dr. Wong Jun Shyan,
CEO ISEC Healthcare Pty
Diabetes mellitus is a major health affliction among our population. A recent national health survey estimated 9% of our population or about 3 million Malaysians, suffer from this malady.
Types of Diabetes Mellitus (DM)
Generally, DM can be divided into two main types. Type 1 DM refers to a disease in which the age of onset is 30 years or younger. Type 2 DM refers to adult-onset disease, usually above the age of 30 years. By far, the most common type of DM is Type 2, accounting for more than 95% of all diabetic patients.
How does DM progress?
Among the body systems that can be affected by uncontrolled diabetes, the eye often takes the brunt of the disease and literally, with “visible” effects. Essentially, the structure and function of the blood vessels in a diabetic person are altered, making the blood vessel walls prone to hardening, narrowing, leaky, and eventually resulting in poor blood flow. When such changes occur in the eye, it affects the light-sensing layer at the rear of the eye, the retina. For the eye to see well, the retina must be in good health. However, in the early stages of abnormal changes in the retina or diabetic retinopathy, the patient may not notice any symptoms. With the progression of retinopathy, the patient will experience blurring in their vision.
This blurriness is usually caused by fluid and fat leakages from abnormal blood vessels in the retinal layer, making the nerve layer swollen. This will alter the structure of blood vessels around the eyes to the point of being blocked. When this happens, the retina will be starved of oxygen and nutrients. This will lead to permanent damage to the eye and vision.
Diabetic retinopathy is present in about 70% of all DM patients after 10 years of diabetes. Almost all patients will suffer from retinopathy after 20 years of the disease. Diabetes has resulted in it being the leading cause of acquired blindness in the adult population. A diabetic patient is 25 times more likely to suffer from vision impairment compared to a non-diabetic person.
There have been highly effective treatments for retinopathy, primarily with the use of laser, for some 30 years now. Prior to the introduction of laser in treating diabetic retinopathy, about 10% of patients with severe retinopathy would go blind each year. With appropriate and timely laser treatment, the risk of blindness is reduced by more the 90%.
Anti-Vascular Endothelial Growth Factor (VEGF) is a type of biologic compound that has now become a gold standard in the treatment of diabetic patients with swelling of the retina (macular edema) due to leakages from the damaged retinal blood vessels in people with diabetic retinopathy. Patients who received timely anti-VEGF therapy had good improvement in their vision, and the majority can prevent further vision loss too.
However, repeated treatment will be necessary to achieve stability in this group of patients. Apart from being enrolled in a life-long eye check-up program, it is important for the patient to be aware of the control of blood sugar on the development of diabetic complications. It has been shown beyond doubt, that strict control of blood sugar levels in both Type 1 and Type 2 DM (with regular monitoring of the blood sugar level), can prevent and retard the progression of diabetic complications, including that of the eye, heart, and kidney damages. Moreover, if the patient has co-existing high blood pressure, studies have also proven that strict control of the blood pressure was beneficial in reducing the severity and retarding the progression of diabetic complications.