Visual pathway function in adults born preterm with very low birth weight: a two-country birth cohort study.

Purpose: To investigate if preterm birth with very low birth weight (VLBW; birth weight < 1500 g) affects macular and visual pathway function in an adult population and explore if best corrected visual acuity (BCVA) was associated with any of the electrophysiologic responses.

Methods: Fifty participants born preterm with VLBW and 77 term-born controls years were recruited when aged 31-41 years from the Helsinki Study of Very Low Birth Weight Adults (Finland) and the NTNU Low Birth Weight Life study (Norway) studies. Pattern reversal electroretinogram (PR-ERG), visual evoked potential (PR-VEP) and BCVA were examined. PR-ERG components (P50, N95 peak time, amplitude and N95:P50 amplitude ratio) and PR-VEP components (N75, P100 and N145 peak time and amplitude) in the better-seeing eye were compared between the groups, and association with BCVA was examined.

Results: The VLBW group showed longer N145 peak time compared to the control group (mean difference 6.8 ms, CI 2.0 to 11.5, p = 0.006) and lower N95:P50 amplitude ratio (CI - 0.3 to - 0.1, p = 0.003). Otherwise, both groups showed similar electrophysiological waveforms. No relationship was found between electrophysiologic responses and BCVA. BCVA was normal in birth groups and showed no group difference.

Conclusion: The responses in the primary visual cortex (N75 and P100) to visual stimuli presented to the better-seeing eye were similar in adults born preterm with VLBW and term-born controls. However, in the VLBW group, there was an indication that subtle electrophysiological deviation may exist at a higher cortical level (N145) and in the ganglion cell response in the macula. These significant differences were not related to reduced visual acuity.