Abstract
Purpose :
To analyze the visual function by electroretinogram (ERG) using EvokeDx® (Konan Medical USA) system in healthy adults. In the system, patterned stimuli were shown repeatedly and averaged to obtain ERG waveforms which were converted into the frequency-domain using a Fourier transform.
Methods :
Twenty-nine eyes of 29 healthy adults (16 males) participated, and the data of left eyes were analyzed. Those who had high myopia (>6 diopters) were excluded. Mean age was 32.2 ± 7.1 years (range 22 to 48) and mean refractive error was -2.3 ± 2.2D (range -5.9 to +1.4D). The ERG was recorded using stripe-patterned stimuli of size 1 (thickest) to 6. The frequency component was compared with background brain activity recorded as noise, and the data were expressed by signal-to-noise ratio (SNR). Measurements were performed twice, and the greater value was analyzed. Macular volume in each layer was evaluated using optical coherence tomography (Heidelberg Spectralis OCT, Heidelberg Engineering GmbH, Dossenheim, Germany). Pearson correlation coefficient (IBM SPSS Statistics version 24.0) was used to evaluate the data, and p<0.05 was considered to be significant. The study adhered to the tenets of the Declaration of Helsinki, was approved by the Ethics Committee of Keio University School of Medicine (Tokyo, Japan; 20150116), and was registered as UMIN000017845. Informed consent was obtained from all subjects.
Results :
The SNR scores were negatively correlated with age at stimulus size 4 (r=-0.381, p=0.041) and 5 (r=-0.373, p=0.046), but were not correlated with refraction error. The SNR score was correlated with macular volume in the retinal nerve fiber layer within 6 mm circle diameter from the fovea at size 4 (r=0.388, p=0.038), although there were no correlations with the other layers.
Conclusions :
The SNR scores of ERG recorded using EvokeDx® system were correlated with age and macular volume in healthy adults. The system may detect slight differences in the visual function related to age and/or retinal morphological variations.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.