Visual and cerebral sequels of VLBW in adolescents

Abstract

Objective: To describe the visual functions and relate them to magnetic resonance imaging (MRI) findings and to the intellectual level in adolescents born with very low birth weight (VLBW).

Design: A population-based case-controlled study.

Patients: Fifty-nine 15-year-old VLBW subjects and 55 gender and age matched controls, with normal birth weight.

Main outcome measures: Objective clinical findings (visual acuity, stereo acuity and cycloplegic refraction) were recorded. Structured history taking was used to identify visual difficulties. The intellectual level was assessed with the Wechsler Intelligence Scale for Children (WISC). All VLBW subjects underwent MRI of the brain.

Results: Significant differences were found between the VLBW subjects and controls regarding VA (medians -0.11 and -0.2 [p=0.004]), stereo acuity (medians 60’’ and 30’’ [p<0.001]), prevalence of astigmatism (19% and 0% [p<0.001]) and in FSIQ (mean IQ 85 and 97 [p<0.001]) and PIQ (mean 87 and 99 [p=0.002]). The structured history revealed significant differences between the groups. Thirty percent of the VLBW subjects had abnormal MRI findings and performed worse in all test, both compared to the VLBW subjects without MRI pathology and to the normal controls.

Conclusion: This study confirms previous observations that adolescents with VLBW are at a disadvantage regarding visual outcome compared to subjects with normal birth weight. Visual dysfunction was in 47% associated with abnormal MRI findings and in 28% with learning disabilities, and subjects with abnormal MRI had more pronounced visual and cognitive dysfunction. The findings indicate a cerebral causative component responsible for the visual dysfunction seen in the present study.