Retinopathy of prematurity in Denmark. Epidemiological considerations and screening limits.

The epidemiology of retinopathy of prematurity (ROP) in Denmark is analysed based on two sources. Regional experience is presented from 12 years' prospective ophthalmic control of infants at risk, in a Danish county with population 342,000 and 44,805 liveborns over the period 1982-93. Out of 127 subjects with ROP 101 reached stage 1 or 2 only; 26 progressed to at least stage 3. Seven with blindness due to ROP amounted to 15.6/100,000 liveborns, a high frequency. The trend over the twelve years was towards less serious sequelae. Currently, the national screening limits for ROP have been adjusted under guidance from the compulsory registration of childhood visual impairment; with birth years 1974-94 there were 157 ROP-children in the register. Blindness due to ROP is now seen only in the very immature. It is suggested that gestational age 30 weeks will soon replace the present limits of less than 32 weeks/1750 g.