Blue light blind-spot stimulation upregulates b-wave and pattern ERG activity in myopes

Ana Amorim-de-Sousa,Paulo Fernandes,Tim Schilling,Yeshwanth Seshadri,Hamed Bahmani,José Manuel González-Méijome

doi:10.1038/s41598-021-88459-2

Abstract

Upregulation of retinal dopaminergic activity may be a target treatment for myopia progression. This study aimed to explore the viability of inducing changes in retinal electrical activity with short-wavelength light targeting melanopsin-expressing retinal ganglion cells (ipRGCs) passing through the optic nerve head. Fifteen healthy non-myopic or myopic young adults were recruited and underwent stimulation with blue light using a virtual reality headset device. Amplitudes and implicit times from photopic 3.0 b-wave and pattern electroretinogram (PERG) were measured at baseline and 10 and 20 min after stimulation. Relative changes were compared between non-myopes and myopes. The ERG b-wave amplitude was significantly larger 20 min after blind-spot stimulation compared to baseline (p < 0.001) and 10 min (p < 0.001) post-stimulation. PERG amplitude P50-N95 also showed a significant main effect for ‘Time after stimulation’ (p < 0.050). Implicit times showed no differences following blind-spot stimulation. PERG and b-wave changes after blind-spot stimulation were stronger in myopes than non-myopes. It is possible to induce significant changes in retinal electrical activity by stimulating ipRGCs axons at the optic nerve head with blue light. The results suggest that the changes in retinal electrical activity are located at the inner plexiform layer and are likely to involve the dopaminergic system.

Highlights

Considering the increasing evidence of a rapid myopic trend in the younger cohorts of the global population, regulation of myopia progression has become a priority for the scientific community, eye care practitioners and policy makers
Tukey-corrected post-hoc tests showed that the b-wave was significantly larger after 20 min compared to baseline (p < 0.001) and 10 min (p < 0.001) after stimulation of the blind-spot with blue light
To the best of our knowledge, the present study is the first evaluating the effect of stimulating the blind-spot with blue light using a virtual reality (VR) system on the electrophysiological response of the human retina

Summary

Introduction

Considering the increasing evidence of a rapid myopic trend in the younger cohorts of the global population, regulation of myopia progression has become a priority for the scientific community, eye care practitioners and policy makers. The progressive loss of retinal dopaminergic neurons and the consequent impact on dopamine regulation was strongly correlated with a latency delay and amplitude reduction observed in visual evoked potentials (VEPs) and PERGs of Parkinson’s disease patients when compared with healthy controls[16]. This decrease in PERG responses observed in Parkinson’s disease patients can be reversed with levodopa therapy[17]. Even patients in the early stages of Parkinson’s disease show the bioelectrical dysfunctions of the retina related to dopamine deficiency This was evident by a reduction of mean amplitudes of several ERG tests, including a reduction in the photopic b-wave. Melanopsin-expressing ipRGCs are a potential target system for a physiological enhancement of DA levels in the myopic eye, as they have been shown to project via their axon collaterals onto DACs23 and thereby modulate DA levels in response to light[24,25]

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