Very Low Birth Weight Can Reduce Visual Function for Life

Visual function and self-reported vision-targeted health is lower for adults who were born preterm with very low birth weight (VLBW) compared with adults who were born at term, according to the results for a birth cohort study published in Acta Ophthalmologica. The study assessed participants in their 30s to 40s who were born premature with VLBW compared with their peers who were born at term. 

The “premature phenotype” is characterized by a high level of morbidity, including loss of visual function, but little data exists regarding these visual impairments beyond childhood.

Researchers evaluated 2 cohorts of participants (N=295) from the Helsinki Study of Very Low Birth Weight Adults (HeSVA) and the NTNU Low Birth Weight in a Lifetime Perspective study (NTNU LBW Life). Participants were divided into a very low birth weight group (n=137) and a term-born control group (n=158). Visual function was evaluated by eye examination and the National Eye Institute Visual Function Questionaire-25 (NEI VFQ-25) was used to collect self-reported measures of general and ocular health.

Two participants in the very low birth weight group were blind due to retrolental fibroplasia. Best-corrected visual acuity as measured by mean Early Treatment of Diabetic Retinopathy Study (ETDRS) letter score was lower for the VLBW group compared with the control group (HeSVA cohort: mean difference, -3.8; 95% CI, -6.6 to -1.5; P =.02; NTNU LBW Life cohort: mean difference, -5.58; 95% CI, -8.6 to -2.9; P =.003). Mean contrast sensitivity was lower across all spatial sensitivities for the VLBW group compared with controls, although not all differences were statistically significant. There were no significant differences in spherical equivalent, visual field, or intraocular pressure. 

The number of participants without a driver’s license was higher in the very low birth weight group compared with the control group (21% vs 8%; P =.001). Additionally, self-reported vision-targeted health status was significantly lower for most subscales for the VLBW group compared with participants in the control group, including general health, general vision, ocular pain, near and distance activities, social functioning, role difficulties, and peripheral vision. 

Although previous studies have shown comparable results in pediatric and young adult populations, this study is the first to report these trends for adults in their 30s and 40s. These data suggest that visual impairment may be a life-long complication of prematurity and is not restricted only to individuals affected by retinopathy of prematurity. 

“While the underlying mechanisms and sites of injury are unknown, it is conceivable that visual impairment is one of the life-long consequences of being born preterm and that it may impact function in other areas of life,” according to the study authors. Although the underlying mechanisms have not been elucidated, the researchers explain that “it has been proposed that lower visual function in preterm-born individuals has a common underlying mechanism with injury to neurovascular tissue in both the retina and the brain, in a syndrome that has been coined Visuopathy of Prematurity (VOP). The present study supports this hypothesis.” 

The study was limited by a few notable factors. First, the NEI VFQ-25 is the best-recognized measure of patient-reported outcomes for visual function but it has not been fully validated for Norwegian and Finnish populations. Additionally, of the individuals invited to participate in the study, 43% were lost to follow-up.