Author: Victoria Stapley
Co-authors: Roger Anderson, Kathryn Saunders, Padraig Mulholland
Abstract
PurposeInvestigating retinal function in myopia can help identify potential biomarkers for myopic progression. Previous research suggests changes in the electroretinogram (ERG) response in myopia, however the invasive nature of the electrode and cumbersome equipment required has prevented the widescale uptake of ERG measures. This study investigated whether changes to the ERG response are also apparent in myopia when using a non-invasive skin electrode and a hand-held ERG device (RETeval®, LKC Technologies, Inc.).
Setting/Venue
Centre for Optometry and Vision Science, Ulster University, Northern Ireland.
Method
Monocular, flash ERGs were measured using the RETeval® device according to the ‘ISCEV 6 Step Dark First cd’ protocol in 46 participants with non-pathological myopia (SER -0.50D to -11.25D, median -3.75D, median axial length (AL) 25.4mm) and 47 non-myopic controls (SER +2.00D to -0.25D, median +1.00D, median AL 23.6mm). Measures were performed with pupil mydriasis and Sensor Strip skin electrodes in all observers. The median amplitude and implicit time for each waveform component was compared between the myopic and non-myopic groups. The relationship between ERG output and AL was also examined.
Results
The median implicit time for all dark-adapted (DA) components was longer in the myopic group. Post Holm-Bonferroni correction, this difference reached statistical significance (p<0.05) for the DA 3.0 A-wave, DA 10.0 A-Wave and B-wave, and DA Oscillatory potentials 1 and 2. There were no significant differences between median LA implicit times or response amplitudes (DA and LA) between groups. For all DA components there was a significant, positive correlation between implicit time and AL. There were no significant relationships between AL and response amplitudes or LA implicit times.
Conclusions
Subtle changes in implicit times of the DA response were evident in the myopic cohort when measured with the RETeval device. The relationship between DA implicit times and AL indicates that DA implicit times may provide an objective biomarker of altered retinal function in progressive myopia. Longitudinal studies are required to confirm this.
Financial Disclosure
This work was supported by a PhD studentship from the Department for the Economy, Northern Ireland (VS). Research support (instrument loan) and conference travel costs (VS) were provided by LKC Technologies Inc.