Ophthalmological follow up of preterm infants: a population based, prospective study of visual acuity and strabismus

Background/aims-Prematurely born infants are known to have an increased rat e of ophthalmological morbidity. The aim of the present study was to invest igate visual acuity and ocular alignment in a population of preterm infants in a geographical area, in infants with and without retinopathy of prematu rity (ROP). Methods-A prospective population based study of ophthalmological status of preterm infants with a birth weight of 1500 g or less was performed during 3.5 years, with examinations at 6, 18, 30, and 42 months of corrected age. Visual acuity was tested using linear optotypes. Multiple regression analys es were used to analyse independent risk factors for poor vision and strabi smus. Results-Poor vision (<0.3) was detected in 2.5% (6/237) of the children. Of these, only two (0.8%) had a severe visual impairment (<0.1). Strabismus o ccurred in 13.5% (31/229). Children with cryotreated ROP and neurological c omplications ran the highest risk of poor vision and strabismus, according to multiple regression analysis. Among children without a history of ROP or neurological complications, 34% had a visual acuity <0.7 and 5.9% had stra bismus, compared with 61% and 22%, respectively, among the children with RO P or neurological complications. Conclusions-The overall incidence of subnormal vision and strabismus in chi ldren born prematurely was higher than in a full term population of the sam e age. On the basis of this study, follow up of all preterm infants screene d for ROP is recommended and general guidelines are suggested.