Visual function in school-aged children born before 29 weeks of gestation: a population-based study.

The aim of this study was to assess visual function, including visual perception, in a geographically-based population of school-aged children, with a median age of 7.2 years (range 5.1 to 9.3 years), born before 29 weeks of gestation to mothers living in Goteborg, Sweden. Fifty-one preterm children participated in the study, six of whom had known brain lesions. Visual acuity, visual fields, stereoacuity, and visual perception were tested. The Test of Visual Perceptual Skills Revised (TVPS-R, Gardner 1996) was used to measure visual perception, and the results were compared with those of 50 term (control) subjects. Six percent of the preterm children were visually impaired, with a visual acuity of less than 0.3 (6/18), while 42% of all the preterm children and 34% of those without known brain lesions had a total score below the 5th centile of the reference material for the test, compared with 14% of the control subjects. In conclusion, visual-perceptual problems seem to be common among very preterm children and should be screened for and assessed before the children start school.