Abstract
Purpose :
The existing literature lacks comprehensive data on the long-term variability in multifocal electroretinogram (mfERG) recording quality. To address this gap, we conducted a retrospective chart and data review study aimed at evaluating the changes in amplitude and signal-to-noise ratio (SNR) over a 6-month period between two mfERG recordings.
Methods :
This retrospective study analyzed patient charts and data from the USF Eye Institute in Tampa, Florida. We included patients who underwent initial mfERG testing and a subsequent follow-up mfERG 6 months later. The mfERG recordings were performed on both eyes using the Espion system (Diagnosys LLC, Lowell, MA) with fiber electrodes. The standard protocol involved 61 hexagonal elements, 60 degrees horizontal size, and 420 cd/m2 maximal brightness. We focused on measuring the P1 amplitudes (in nV) and SNR (in dB), using a paired t-test for statistical comparison of corresponding values between the two recordings. Additionally, two-way ANOVA was used to estimate the effect of time on the values that were compared.
Results :
The study comprised 25 patients (22 female and 3 male) with an average age of 57.8 ± 13.2 years. Analysis of the average P1 amplitude from all 61 hexagonal elements revealed no significant increase from the initial test to the 6-month follow-up for the right eyes (198.40 nV to 201.63 nV, p > 0.05), but a significant increase was seen in the left eyes (188.38 nV to 198.70 nV, p < 0.001). A two-way ANOVA test confirmed this result, showed no effect of time for the right eyes (p > 0.05), and a statistically significant effect of time for the left eyes (p < 0.001). The average SNR from all 61 elements showed no significant change between the two tests for both right (4.76 dB to 4.84 dB, p = 0.36) and left eyes (4.50 dB to 4.62 dB, p = 0.13). This result was confirmed by a two-way ANOVA test which showed no effect of time for both right and left eyes (p > 0.05).
Conclusions :
Our study indicates a significant increase in P1 amplitude values for the left eye, but no significant changes in SNR in mfERG recordings over a 6-month period. This stability in recording quality suggests that repeat mfERG testing after a prolonged interval may not yield significant variations in SNR values, reinforcing the reliability of mfERG for monitoring retinal function over time.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.