To Örebro University

PURPOSE: The Extremely Preterm Infants in Sweden Study (EXPRESS) followed a national cohort of extremely preterm born (EPT, i.e. <27 weeks) children until 12 years of age. This study aimed to investigate the longitudinal development of visual acuity (VA) in children born EPT, explore the predictive value of early visual assessments, and evaluate risk factors for visual impairment at the age of 12 years.

METHODS: All 462 children born EPT in Sweden during April 2004-March 2007, and surviving to age 6.5 years, and full-term born matched controls were invited to participate in the 12-year follow-up. VA was assessed at 12 years and the results were compared with values at 2.5 and 6.5 years.

RESULTS: At age 12, 332 (72%) EPT survivors and 189 controls were examined. The mean VA in the EPT group was lower than in the control group (1.15, 95%CI [1.12-1.19] vs. 1.33, 95% CI [1.29-1.37]). Fifteen (4.5%) EPT had visual impairment. The examination at age 2.5 failed to identify most of them, while the examination at 6.5 could predict the final visual outcome at 12. Risk factors for visual impairment were low gestational age, moderate and severe intraventricular haemorrhage, treatment-requiring retinopathy of prematurity, cerebral palsy, and cognitive disability.

CONCLUSION: In this national cohort, the VA outcome at age 12 was lower in children born EPT than full-term controls. As eye examination at 2.5 years did not reliably identify visual impairment, clinical risk factors should be considered in the screening of children born EPT to early identify the visually impaired.