Abstract
Purpose :
To obtain Visual Evoked Potential (VEP) and Pattern Electroretinography (PERG) measured outcomes of ocular hypertensive (OHT) patients with thick and thin corneas and not receiving treatment to determine if the VEP and PERG parameters are affected by central corneal thickness (CCT).
Methods :
Twenty-two subjects, with OHT and with CCT ranging from 317µm to 668 µm were tested with Diopsys NOVA Vision Testing System’s Contrast PERG and Multi-contrast VEP protocols to measure their electrophysiological visual function response. Each patient was tested three times with each protocol in both eyes. The Pearson product moment correlation coefficient (r) was calculated for the influence of CCT on IOP. The correlation was also calculated between the VEP/PERG parameters and both the CCT and IOP to determine the effects of the CCT and IOP on the visual function response.
Results :
The Pearson’s r for the correlation between CCT and IOP was 0.239 (95% CI: -0.031 to 0.476, p=0.082), which suggests that there may be an influence of CCT on IOP. Tables 1-4 show the correlation between the VEP/PERG parameters and CCT and between the VEP/PERG and IOP. The CCT did not have a significant effect on the PERG parameters. The CCT had no significant effect on either the low contrast (Lc) or high contrast (Hc) N75 parameters, nor was there an effect on Lc P100 latency. However, CCT had a significant effect on the Lc P100 and Hc P100 amplitudes and the Hc P100 latency.
Conclusions :
The CCT does appear to affect the Lc and Hc P100 components of the VEP with the exception of the Lc P100 latency. The Lc and Hc N75 component is not dependent on CCT. The CCT did not appear to alter the PERG parameters, which indicates that the function of the retina is not affected. The Lc and Hc N75 VEP parameters and the PERG parameters represent the visual function of the eye independent of the corneal thickness of patients with OHT. Since the IOP maybe under/overestimated depending on CCT, VEP/PERG parameters will be useful in aiding the clinician in determining when to treat patients with apparent OHT.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.