Abstract
Purpose :
The aim of this project is to replicate the study of Brûlé et al., 2007, which shows a decreased amplitude of electroretinogram in men of about 30%, but this time using much less invasive dermal electrodes than the traditionally used DTL electrodes.
Methods :
Full-field photopic and scotopic ERGs were performed with an Espion E3 system (Diagnosys LLC, Lowell, MA). Recordings were obtained in nondilated eyes using self-adhesive skin electrodes (LKC Technologies, Gaithersburg, MD) applied 2 mm below the eyes. ERGs were performed in 25 subjects (16 women [27.1 +/- 4.7 years]; 9 men [28.1 +/- 4.8 years]). The photopic ERG was performed with a background light set at 80 cd/m2 and using 7 white flashes (luminance ranging from 1.33 to 50 cd.s/m2). The scotopic condition was performed after 20 minutes of dark adaptation using 12 green flashes (peak: 509 nm) (luminance ranging from 0. 001778 to 1 cd.s/m2). Each flash intensity was repeated twice (20 flashes per trial) and averaged for both eyes.
Results :
In photopic conditions, and at the intensity allowing maximum amplitude (7.5 cd.s/m2), men (M) demonstrated when compared to women (W), an 18% lower cone a-wave amplitude (p=0.017 [M mean=-7.9; s.d.=1,3 mV] [W mean=-9,9 mV; s.d.=2,4 mV]) and a 23% lower cone b-wave amplitude (p=0.002 [M mean=36,6 mV; s.d.=7,2 mV] [W mean=47,6 mV; s.d.=8,8 mV]). In scotopic conditions and at the intensity allowing maximum pure rod response (0.1 cd.s/m2), men demonstrated a 24% lower b-wave amplitude (p=0.001 [M mean=60,8 mV; s.d.=8,4 mV] [W mean=80,2 mV; s.d.=15 mV]. At the maximum intensity used (1 cd.s/m2), men exhibited a 25.5% lower mixed cone and rod b-wave amplitude (p<0.001 [M mean=69,9 mV; s.d.=10 mV] [W mean=93,8 mV; s.d.=14,8 mV]).
Conclusions :
The data obtained replicate those shown by Brûlé et al., 2007. More and more researchers are interested in using the ERG to detect biomarkers in mental health. The present project demonstrates the importance of considering biological sex in this field. The difference in ERG amplitudes between men and women increases the variability within groups when not accounted for, reducing the overall statistical power of the projects. The data also validates the use of the less invasive dermal electrodes, as they replicate the results obtained with traditional DTL electrodes, albeit smaller amplitudes are achieved which is not a concern when investigating a normal eye.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.