Regional differences in screening for retinopathy of prematurity in infants born before 27 weeks of gestation in Sweden--the EXPRESS study

Acta Ophthalmol. 2014 Jun;92(4):311-5. doi: 10.1111/aos.12165. Epub 2013 Jun 20.


Purpose: The primary aim was to analyse regional incidences of retinopathy of prematurity (ROP) and frequencies of treatment and their relation to perinatal risk factors during a 3-year period. A secondary aim was to study adherence to the study screening protocol in the different regions.

Methods: A population-based study of neonatal morbidity in extremely preterm infants in Sweden (EXPRESS) was performed during 2004-2007. Screening for ROP was to start at postnatal age 5 weeks and to continue weekly until the retina was completely vascularized or until regression of ROP. Logistic regression analyses were used for evaluation of differences in incidence of Any ROP, ROP 3 or more and ROP Type 1 between the seven regions of the country.

Results: The regional incidence of ROP varied between 54% and 92% for Any ROP, between 25% and 43% for ROP stage 3 or more and between 8% and 23% of infants with ROP Type 1, all of whom were treated. There was no significant difference between the regions regarding ROP Type 1, even when adjusting for known risk factors for ROP.

Conclusion: The heterogeneity between the regions regarding the incidence of ROP was reduced with increasing severity of ROP, and there was no heterogeneity regarding frequency of treatment for ROP, which is the most important issue for the children. We cannot exclude observer bias regarding mild ROP and ROP stage 3 in this study.

Keywords: extremely preterm; population-based; retinopathy of prematurity; screening, observer bias.

MeSH terms

  • Birth Weight
  • Gestational Age*
  • Humans
  • Incidence
  • Infant, Extremely Low Birth Weight
  • Infant, Extremely Premature*
  • Infant, Newborn
  • Neonatal Screening*
  • Odds Ratio
  • Retinopathy of Prematurity / diagnosis
  • Retinopathy of Prematurity / epidemiology*
  • Risk Factors
  • Sweden / epidemiology
  • Vision Screening*