Diabetes mellitus is on the increase and seems to be emerging as a major public health problem for our country. Interestingly, for every patient who is known to have diabetes, another has the disease but is unaware of it. It is a multisystem disorder, including cardiovascular disease, renal failure, peripheral neuropathy, and retinopathy which may lead to blindness. The relationship of diabetes mellitus and retinopathy is most interesting. It has been reported in the literature from the developed world that 20 years after the onset of diabetes, nearly all patients with type I diabetes (insulin-dependent) and more than 60% of those with type II diabetes (non-insulin dependent) will have some degree of retinopathy. However, this also depends on the degree of metabolic control of diabetes.

Diabetic retinopathy is a leading cause of blindness amongst the working class (<55 years old) in the industrialized countries. The emerging scenario in the developing world suggests that diabetes and blindness secondary to diabetic retinopathy may soon be a major problem in this part of the world as well. Unfortunately, India has no figures for diabetic retinopathy as a cause for blindness as no proper survey has been carried out as yet. Our blindness figures still rest on the decade-old National Programme for Control of Blindness survey carried out in the mid-eighties.

Screening for diabetic retinopathy should be mandatory for all diabetics as diabetes mellitus is now assuming alarming epidemic proportions in the developing countries due to an increasingly inappropriate diet high in fat and carbohydrates, sedentary life styles, and obesity. Hence, screening for retinopathy is important. This should consist of dilated fundus examination of the diabetics at least once a year. This could best be achieved by a National Diabetic Retinopathy Screening Programme. Basic requirements for such a screening programme include identification of the population at risk, an efficient recall system so that patients are not lost to follow-up, an effective instrument for retinal viewing (an ophthalmoscope or a non-mydriatic fundus camera), an experienced interpreter of the findings, a screening protocol defining clinical parameters for referral and treatment, a system for effective management of the identified cases and their feedback, and finally, quality control.

Information obtained from various randomized control trials such as Diabetes Control and Complication Trial,[2] Diabetic Retinopathy Study,[3] Early Treatment of Diabetic Retinopathy Study,[4] and Diabetes Retinopathy Vitrectomy Study[5] are valuable both from overall health planning and individual treatment points of view. Good glycemic control can markedly reduce the retinopathy in patients with type I diabetes. Timely laser surgery can reduce risk of visual loss from proliferative diabetic retinopathy by 90%. Timely laser for diabetic macular edema can reduce the risk of moderate visual loss by 50%. Vitrectomy surgery may restore useful vision when retinopathy is too advanced for laser treatment.

Handling of the increasing problem of diabetes mellitus and its danger to sight should also include effective education and communication with the patients on the one hand, and with general ophthalmologists, primary care physicians, diabetologists, and allied health professionals on the other hand.

Dr Amol Wankhede
Retina eye centre, Nasik