Slow flash multifocal electroretinogram in myopia.
OBJECTIVE
The purpose of this study was to investigate the characteristics of retinal function in myopes using a modified multifocal electroretinogram (mfERG) protocol, the slow flash (sf-mfERG) paradigm, which is thought to primarily reflect responses of ON- and OFF-bipolar cells and emphasize the late response components.


METHODS
Twenty-eight subjects (10 emmetropes and 18 myopes) underwent mfERG testing using VERIS 5.1.5X. The sf-mfERG stimulus array consisted of 103-scaled hexagons and flickered according to a pseudorandom binary m-sequence (2(13)-1). The stimulation sequence was slowed by inserting three dark frames such that each step in the m-sequence was four frames long (53.3ms). The amplitude and implicit time of the major sf-mfERG waveform features (N1, P1, and N2) of the first-order kernel were analysed.


RESULTS
Myopes had significantly reduced P1 and N2 amplitudes compared to the emmetropes (F(1,25)=8.818, p=0.007; F(1,25)=6.723, p=0.017). There were no significant differences in N1 amplitude or implicit time between the groups (F(1,25)=1.506, p=0.233; F(1,25)=1.291, p=0.269).


CONCLUSIONS
Late response components (P1 and N2) of the first-order sf-mfERG responses were preferentially affected in myopia, suggesting possible reduced ON- and OFF-bipolar cell activity. As bipolar cells form the first synapse of the visual system with the photoreceptors to initiate the ON- and OFF-pathways, future investigations of ON- and OFF-systems in myopia are of interest.
Chen
Jennifer C
JC
School of Optometry, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia. jc.chen@qut.edu.ca
Brown
Brian
B
Schmid
Katrina L
KL
D000328:Adult; D004596:Electroretinography / Q000379:methods; D005123:Eye / Q000473:pathology; D006801:Humans; D009216:Myopia / Q000473:pathology / Q000503:physiopathology*; D010775:Photic Stimulation / Q000379:methods; D012160:Retina / Q000503:physiopathology*