Flicker electroretinogram in preterm infants

Abstract

Background Infants born prematurely are at risk of developing retinopathy of prematurity, which is associated with abnormalities in retinal function as measured using electroretinography. The aim of this study was to record and analyse non-invasive flicker electroretinograms (ERGs) in preterm infants. Methods In this non-randomized, cross-sectional study, 40 moderate preterm (gestational age (GA) 34 0/7 to 36 6/7 weeks, group A) and 40 very or extremely preterm infants (GA ≤ 31 weeks, group B) were recruited for flicker ERG recording through closed eyelids using the portable RETeval® device and skin electrodes. Group A was tested within the first week of life and group B between 34th and 37th week postmenstrual age. Flicker stimuli were presented at 28.3 Hz with stimulus levels of 3, 6, 12, 30 and 50 cd•s/m2. Primary endpoints were peak time (ms) and amplitude (µV). Results Flicker ERGs were reproducibly recorded in most infants with the highest number of reproducible ERG responses at 30 cd•s/m2. Amplitudes increased with stronger flicker stimulation, while peak times did not differ significantly between stimulus levels nor groups. Amplitudes were significantly greater in Group B at the strongest stimulus level (Mann-Whitney-U-Test = 198.00, Z = - 4.097, p = <0.001). Conclusions Feasibility of collecting flicker ERG data in most preterm infants was confirmed in this study. We found no evidence of reduced retinal responses to flicker stimuli associated with extreme prematurity. Higher amplitudes in infants born very, and extremely preterm could indicate acceleration of retinal development following birth, triggered by visual stimulation.