INCIDENCE OF BLINDNESS AND VISUAL IMPAIRMENT IN DIABETIC-PATIENTS PARTICIPATING IN AN OPHTHALMOLOGICAL CONTROL AND SCREENING-PROGRAM

We studied the incidence of blindness and visual impairment in patient s who were enrolled in a photographic control- and screening program f or diabetic retinopathy. The study cohort consisted of 2133 patients e xamined between January 1990 and December 1992 and followed until Octo ber 1st 1995. The occurrence of blindness (visual acuity less than or equal to 0.1) and moderate visual impairment (visual acuity 0.2-0.4) w as assessed. The Wisconsin scale was used to grade retinopathy. The me an HbA(1c) value for the last 8 years was used to represent long-term glycaemic control. Average follow-up time was 2.9 years. Seven patient s were blind and 24 had visual impairment caused by retinopathy at the entry of the study. Six patients went blind due to retinopathy during the study period, corresponding to an incidence of 1.0 per 1000 perso n-years (95% confidence interval 0.4-2.1), and 28 became visually impa ired, corresponding to an incidence of 4.6 per 1000 person-years (95% confidence interval 3.0-6.6). Multivariate analysis showed a statistic ally significant association between blindness/visual impairment and o ld age, long duration of diabetes, and poor glycaemic control. HbA(1c) values in the highest quartile, i.e greater than or equal to 8.5%, we re associated with a 65% increase in risk of blindness/visual impairme nt (95% confidence interval 14-130%). Retinopathy was the major cause of blindness and visual impairment in patients with diabetes. The stud y revealed a low incidence of blindness, which is in line with recent reports. Control of hyperglycaemia may be of value for the prevention of visual loss.