Diabetic retinopathy : a cost-effectiveness analysis of ophthalmoscopy and photocoagulation

Within twenty years after the onset of diabetes mellitus (DM), the prevalenee of diabetic retinopathy (DR) reaches the following maxima: 98% for IDDM patients (age of onset <30 years); 95% and 72% for insulin taking and not-insulin taking NIDDM patients (age of onset ;:,30 years). At first, DR darnages the functioning of !he retina only in some eyes perceptibly, but after some years it seriously threatens the vision of numerous eyes. Ultimately, 14% to 35% of the diabetic patients become visually impaired and 6% to 12% blind. In the Uniled States, DR is the most important cause of blindness for ages between twenty and seventy-four years. So far, no medica! therapies have proved to be effective against DM or DR. According to newspaper-reports, some results of the Diabetes Control and Complications Trial will be published shortly. They are said to demonstrate unambiguously, that strict metabolic control significantly reduces the likelihood of complications like DR arnong IDDM patients. In the earlierhalf of the eighties, clinical investigations have indisputably established, that timely laser treatrnents prevent, or significantly delay, the occurrence of poor eyesight and blindness in more than half the treated eyes. Patients usually perceive the first symptoms of DR long after the moment when the condition of retina enables laser treatrnents to reach !heir highest effectiveness. lt is then quite probable that only surgery may preserve a limited fraction of the eyesight. Therefore, diabetic patients should receive frequent ophthalmic examinations, so that indications for laser treatments can be diagnosed timely. This obviously raises the question how frequently patients should be screened. How much blindness and poor eyesight can various scenarios of ophthalmic care prevent? Which resources do these scenarios require regarding personnel, matériel and finances? Which savings in production losses and facilities provided for disabilities do they realise?