title: Visual impairment is common in children born before 25 gestational weeks--boys are more vulnerable than girls.
abstract: BACKGROUND
  Children born extremely preterm have high risk of visual impairment due to retinopathy of prematurity (ROP) and cerebral lesions.
  
  
  OBJECTIVE
  The aim of this study was to investigate the frequency of ROP and visual impairment as defined by the World Health Organization (WHO), with respect to gender in two hospital-based groups of children born at the limit of viability.
  
  
  METHODS
  A retrospective chart review was conducted for all children (n = 114), born before 25 gestational weeks and screened for ROP at Karolinska hospital in Stockholm and Sahlgrenska hospital in Gothenburg between 1990 and 2002. Maximal ROP stages, treatment for ROP and visual acuity (VA), with correction when needed at latest available visit, were recorded.
  
  
  RESULTS
  Altogether 97.4% had ROP, 74.6% developed proliferative disease (stage >/= 3) and 63.2% were treated with retinal ablation. Normal VA (>/=0.8) in at least one eye was found in 50.5% of all and in significantly more girls (61.5%) than boys (34.8%) (p = 0.006), while visual impairment (VA < 0.33) was more common in boys (32.6%) than in girls (9.2%) (p = 0.004).
  
  
  CONCLUSIONS
  A large proportion of children, especially boys, born at the level of viability are visually impaired with low vision or blindness. Development of preventive measures is urgent.
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden. lena.jacobson@karolinska.se
authors.forename: Lena
authors.initials: L
authors.lastname: Jacobson
authors.forename: Anna-Lena
authors.initials: AL
authors.lastname: Hård
authors.forename: Eva
authors.initials: E
authors.lastname: Horemuzova
authors.forename: Hannah
authors.initials: H
authors.lastname: Hammarén
authors.forename: Ann
authors.initials: A
authors.lastname: Hellström
mesh_terms: D001766:Blindness / Q000453:epidemiology*; D002675:Child, Preschool; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000453:epidemiology*; D008297:Male; D012178:Retinopathy of Prematurity / Q000453:epidemiology*; D012189:Retrospective Studies; D017678:Sex Distribution; D012737:Sex Factors