Background: Retinopathy of prematurity (ROP) is one of the few causes of child hood blindness in which severe vision impairment is largely preventable. Ophthal mic screening for ROP is required to identify disease that requires treatment wh ereby the development of potentially blinding disease can be minimised. Objectiv es: To make the first UK population based estimate of the incidence of babies wi th severe ROP (stage 3 or more); to document their clinical characteristics and management and to evaluate the appropriateness of current ROP screening guidelin es in the UK. Patients: Cases were recruited through a national surveillance pro gramme with 1 year ophthalmic follow up and data from clinician completed questi onnaires. Results: Between 1 December 1997 and 31 March 1999, 233 preterm babies with st age 3 ROP were identified. Severity (location, extent, and presence of plus dise ase) was associated with degree of prematurity, most severe in the most prematur e babies. Fifty nine percent were treated. The UK screening protocol was followe d in two thirds of cases, but in the remainder itwas begun too late orwas too in frequent. Three quarters of the cases were followed up at 1 year, and 13%had a severe vision deficit as a result of ROP. Conclusions: Visual deficit as a resul t of ROP in premature babies continues to be a severe disability in some of the survivors of neonatal intensive care. Further efforts are needed to organise tre atment regionally to improve outcome and standards of practice. Background: Retinopathy of prematurity (ROP) is one of the few causes of child hood blindness in which severe vision impairment is largely preventable. Ophthalmic mic screening for ROP is required to identify disease that requires treatment wh ereby the development of potentially blinding disease can be minimized. Objectiv es: To make the first UK population based estimate of the incidence of babies wi th severe ROP (stage 3 or more); to document their clinical characteristics and management and to evaluate the appropriateness of current ROP screening guidelin es in the UK Patients: Cases were recruited through a national surveillance pro gramme with 1 year ophthalmic follow up and data from clinician completed questi onnaires. Results: Between 1 December 1997 and 31 March 1999, 233 preterm babies with st age 3 ROP were identified. Severity ( location, extent, and presence of plus dise ase) was associated with degree of prematurity, most severe in the most prematur e babies. Fifty nine pe The UK screening protocol was followe d in two thirds of cases, but in the remainder itwas begun too late orwas too in frequent. Three quarters of the cases were followed up at 1 year, and 13% had a severe vision deficit as a result of ROP. Conclusions: Visual deficit as a resul t of ROP in premature babies continues to be a severe disability in some of the survivors of neonatal intensive care. Further efforts are needed to organize tre atment regionally to improve outcome and standards of practice.