Abstract
Purpose :
To evaluate the short- and long-term repeatability of the photopic negative response (PhNR) as an index of retinal ganglion cell function of the full-field electroretinogram (ERG) in stable optic neuropathy (ON), using a handheld, non-mydriatic ERG system and skin electrodes.
Methods :
PhNR amplitude, P-ratio (PhNRamp/Bamp), and W-ratio ((Bamp–PhNRamp)/(Bamp–Aamp)) were measured with a handheld ERG system using full-field, brief-luminance flashes (RetEVAL, LKC Technologies Inc.) in human subjects with stable ON (n = 18) and normal control (n = 9) eyes. Multiple ERG recordings were taken during the same session and across multiple visits to evaluate for short- and long-term repeatability of the measurements. Stability of ON was verified based on optic nerve structure using optical coherence tomography measures of retinal nerve fiber layer and ganglion cell layer thicknesses, visual function using Humphrey Visual Field mean deviation scores, and physician assessment.
Results :
For P- and W-ratios, repeatability across measurements taken during the same session was similar between stable ON and normal control patients. Short-term P-ratio 95% limits of agreement (LoA): stable ON eyes [-0.43, 0.36] and control eyes [-0.66, 0.52]. Short-term W-ratio LoA: control eyes [-0.35, 0.40] and stable ON eyes [-0.53, 0.46]. The W-ratio showed minimal variability for long-term measurements between control (LoA [-0.40, 0.38]) and stable ON eyes (LoA [-0.43, 0.41]).
Conclusions :
PhNR, P-ratio, and W-ratio measurements using a handheld, non-mydriatic ERG system with skin electrodes demonstrated minimal variability over multiple recordings and visits in stable ON and control subjects.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.