Diabetes Mellitus is the body’s inability in handling glucose, due mainly to a combination of insulin deficiency (either relative or absolute) and insulin inaction (termed insulin resistance). In normal individuals, insulin takes glucose from the blood and delivers it to wherever it is required. When this does not happen, blood sugar levels go up, and diabetes occurs. High sugar levels do not cause symptoms. They cause certain changes inside blood vessels, which ultimately damages various organs of the body. Studies have shown that tight control over blood sugar (and blood pressure, if high) can prevent these organ damages.
One of the organs commonly affected in diabetes is the eye. The three eye diseases that might occur in diabetics are diabetic retinopathy, cataract and glaucoma. Although cataract and glaucoma are not limited to diabetics, they occur more commonly in this disease. The common presentations in both these disorders are headache and blurred vision. Diagnosis is fairly simple, and surgical treatment is the same as in non-diabetic individuals. However, careful blood glucose control is absolutely mandatory during and after surgery.
Diabetic retinopathy, as the name implies, is an eye disease that is specific to diabetes. Retina is the part at the back of the eye where light falls after entering the eye and passing through the lens, somewhat similar to a movie projector and the screen; the screen being the retina. The thin blood vessels supplying the retina get affected by the high sugars of diabetics, causing tiny haemorrhages and leaks. At this stage, there are no vision-related problems, so unless routinely checked for, this early retinopathy is likely to be missed.
In some cases, retina undergoes swelling (termed macular edema), which causes blurred vision. Routine eye examination is recommended in all diabetics, as early retinopathy and macular edema needs to be treated with laser therapy, a relatively inexpensive and painless procedure. If missed, later stages of retinopathy are not so easily treatable. If retinopathy is allowed to proceed, new blood vessels start retina. These vessels are weak and may subsequently break down to bleed inside the eye. Since a blood clot id opaque, this causes sudden loss of vision in that eye in part or whole, depending on the size of the clot.
Prior to an actual bleed, proliferative retinopathy can also be managed with laser, but once a bleed occurs, the only discourse is surgery, which is performed at specialised centres. Small bleeds may rarely disappear spontaneously, but may leave behind scar-tissue that might pull at the retina and cause it to detach from the underlying tissue, which might also need surgical repair. To sum up, diabetic eye diseases are an important group of diabetic complications. Regular eye check-up can identify early stages of retinopathy, and treatment at these early stages is relatively simple, with laser therapy. Later stages of the disease may require more specialised surgical care. But as the old age saying goes, “Prevention is always better than cure.”