Visual impairment in Danish children 1985.

In 1985 150 children aged 0-18 were reported to the Danish National Register for Visually Impaired Children. Cross tabulation of the ophthalmological diagnoses by site and type of affection was performed with respect to year of birth, aetiology, visual acuity and birth weight. Finally the relations between aetiology and the presence of additional handicaps are demonstrated. The 'incidence of notification' (IN) was calculated for each birth year as the number of notified children per 100,000 within each birth year group showing variations between 46 in the 1984 birth year group and 3 in the 1970 birth year group with a mean value of 14. The figures stress the impact of congenital and neonatal visual impairment. The significance of IN is discussed with respect to other concepts of incidence. It is concluded that the presented epidemiological method is useful as a tool of analysis in the planning of preventional strategies. From the tables the following main features may be highlighted: Nearly 90% of the blinding causes anatomically are located in the posterior segment of the eye, the optic pathways or in the brain. Isolated visual handicap was notified in 34% of the children, while another 48% presented central nervous system involvement. From an aetiological point of view it is noteworthy that no specific aetiology could be encircled in 38% of the material. In conclusion, it is proposed that future lines of ophthalmological work in the prevention of visual handicap in childhood should concentrate on a higher degree of specificity in diagnostic procedures and an intensified search for specific aetiologies in every single child with visual impairment.