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

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.

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.

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.

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.