Epidemiological study of severe vision impairment in Swiss children with special reference to retrolental fibroplasia

On December 31 1984, 262 children between 7 and 16 years of age were being trained in the major institutions for the visually handicapped in Switzerland. Of these, 173 (66%) were visually impaired and 89 (34%) were blind (i.e. some or no light perception). The causes of the visual impairment were malformations (65%), infectious diseases (14%), retrolental fibroplasia (12%), metabolic disorders (4%), tumors (3%) and accidents (2%). Among the blind children these diagnostic groups were distributed as follows: malformations (53%), RLF (25%), infections (10%), tumors (10%). The rates of blindness within The single diagnostic groups were as follows: accidents: 4 out of 5 children; tumors: 78%; RLF: 69%. This risk of developing blindness in RLF children, as compared to the risk in the overall population studied, had the highest statistical significance (p less than 0.0001). Malformations (28%) and infectious diseases (22%) represented a lower than average risk of developing blindness, the average figure for the whole population being 34%. The risk of developing blindness as a consequence of infections was statistically not different from that in the total population investigated. All RLF children had a birthweight below 2000 g. By extrapolation an incidence of 0.24% RLF cases was estimated for prematures below 2000 g. During the 10 years under investigation (1968-1977), 3.6 new cases of RLF/100,000 live births were diagnosed per year, with a peak in 1975 and 1976. This figure is probably an underestimate, since severely brain damaged blind children with multiple handicaps were not considered.(ABSTRACT TRUNCATED AT 250 WORDS).