Epidemiological and clinical studies on blindness due to diabetic retinopathy.

To clarify the epidemiological and clinical features of blindness due to diabetic retinopathy, 21 patients were studied. Blind diabetics seen at our clinic numbered 2, 3, 4 and 12 in 1965-1969, 1970-1974, 1975-1979 and 1980-1981 respectively. The ratio of males to females was about 4:3. Patients whose onset was in the 10-19, 20-29, 30-39, 40-49 and 50-59 year age group numbered 4, 5, 6, 3 and 3 respectively. No difference was seen in the duration of the disease between patients whose onset was below and patients whose onset was above 40 years of age. Most of the blind diabetics (81.8%) were treated with insulin and hypoglycemic symptoms had occurred on several occasions in 14 cases. Hypertension was a complication in 10 (45%) and orthostatic hypotension in 7 cases (31.8%). Patellar tendon reflex disappeared in 15 cases (68.2%). Proteinuria was strongly positive in 11 cases (52.4%). It was therefore concluded that the number of blind diabetics has been increasing in our clinic since 1975. Insulin therapy and the association of hypoglycemia were thought to be important precipitating factors of blindness in diabetics. The levels of plasma fibrinogen and soluble fibrin monomer complexes in blind diabetics were higher than those in diabetics without retinopathy.