Incidence of blindness in southern Germany between 1990 and 1998

Abstract

Aims/hypothesis. A reduction of diabetes-related blindness by at least one third was declared a primary objective for Europe in 1989 (St. Vincent Declaration). To ascertain a potential change of incidence rates, we collected data on blindness in a German district (population: about 5 million) over 9 years. Methods. We obtained complete lists of newly registered blindness-allowance recipients between 1990 and 1998 and population data on Württemberg-Hohenzollern, Germany. We estimated incidence rates of blindness in the general population and the diabetic population. To ascertain any time trend, we applied Poisson regression models. Results. There were 6371 newly registered blindness allowance recipients (1990-1998). Of these 67% were women and 27% had diabetes. Mean age was 71.7 years. Standardised results in the diabetic population (incidence rates per 100 000 person-years; standard: diabetic population; 95% CI): 1990:72 (61;82); 1991:88 (76;100); 1992:77 (67;88); 1993:82 (71;93); 1994:62 (53;72); 1995:82 (71;93); 1996:70 (60;80); 1997:69 (59;79); 1998:59 (49;68). The Poisson model estimated a 3% decrease of incident blindness in the diabetic population for each year (Relative risk per year 0.97; CI: 0.95; 0.99). No significant change could be observed in the non-diabetic population (Relative risk: 0.99; CI: 0.98; 1.00). Relative risks for each year varied between sub-groups according to sex, diabetic status and cause of blindness between 0.94 and 1.01. Conclusion/interpretation. A slight reduction of incident blindness could be shown but a reduction by one third has not been reached. Several possible sources of bias in the data have to be considered.