Very low birthweight linked to poor visual outcomes in adolescence

NEW YORK (Reuters Health) – Findings published in the July issue of the Archives of Diseases in Childhood–Fetal and Neonatal Edition support previous observations that very-low-birthweight adolescents have poorer visual outcome compared with their normal-birthweight peers.

"Children with very low birth weight (VLBW), less than 1500 g, constitute a heterogeneous group of premature children born small for gestational age or with a birth weight appropriate for gestational age," Dr. Kerstin Hellgren, of the Karolinska Institute, Stockholm, Sweden, and colleagues write. "Within this group, different mechanisms of visual disturbance have been reported."

In a population-based, case-control study, the researchers examined visual functions in 59 15-year-old VLBW adolescents and 55 age- and sex-matched normal-birthweight controls. The team recorded objective clinical findings, including visual acuity, stereo acuity, and cycloplegic refraction.

Significant differences were observed between the VLBW adolescents and controls in terms of visual acuity (median distance binocular, line visual acuity was -0.11 in the VLBW group and -0.2 in the control group, p = 0.004). Subnormal stereo acuity was found in 13 VLBW adolescents (22%) and three controls (5%; p = 0.011). Significantly more VLBW subjects had astigmatism than controls (11/58 versus 0/55) (p < 0.001).

Overall, 20 subjects in the VLBW group and seven in the control group had visual dysfunction (p = 0.009) according to predefined criteria.

Based on a full-scale IQ < 70, 11 VLBW subjects had learning disabilities compared to one control subject (p = 0.002).

Fifty-seven of the VLBW subjects underwent MRI examination. Of these, 17 had abnormal findings.

"Adolescents with abnormal MRI had more pronounced visual and cognitive dysfunction," Dr. Hellgren’s team reports. "Of those with visual dysfunction, half had brain pathology documented with MRI and a third of them had learning disabilities."

The investigators conclude, "The findings indicate a cerebral causative component for the visual dysfunction seen in the present study."

Arch Dis Child Fetal Neonatal Ed 2007;92:F259-F264.