Abstract
Purpose :
Due to a mutation in the RS1 gene, which encodes retinoschisin, a protein involved in cellular adhesion and information transmission between photoreceptors and bipolar cells, individuals with X-Linked Retinoschisis (XLRS) display distinctive electrophysiological features, notably the reduction of the scotopic b-wave. The electrophysiological OPs component emerge between the a- and b-waves and reflect a network comprised of various cells of the inner retina. This study aims to explore the electrophysiological aspect of oscillatory potentials (OPs) in XLRS.
Methods :
We analyzed full-filed ERGs (Diagnosys Ltd., Cambridge, UK) of eleven individuals with XLRS (mean age 29 ±17) and twenty-six controls (mean age 40,±11). The study followed the Declaration of Helsinki. Full-field ERG measured mixed cone-rod signal under mesopic conditions at 3 cd.s/m2, and OPs were extracted by filtering the signal between 70-300Hz. Subsequently, a time-frequency analysis was conducted by convolving a Morlet wavelet to observe the dynamic nature of this component in time (ms) and frequency (Hz) and extract the power (dB). Additionally, implicit time (IT, ms) and amplitude (µV) information of the b-wave were extracted. For data analysis, an independent sample t-test was performed with a significant threshold at p<.05. Furthermore, a correlation matrix was generated to explore relationships between electrophysiological component parameters.
Results :
For OPs, the time-series trace exhibits temporal delay of 2.8 ms compared to the control group. The power of OPs calculated from the time-frequency maps is significantly reduced in comparison to control group (mean power: XLRS=15.67±6.09; controls=28.02,±4.03; p<.0001, t=-6.804). Also, the amplitude and implicit time (IT) of the b-wave are significantly diminished compared to controls (mean amplitude: XLRS=162.77,±55.44; controls=421.7,±100.6; p<.0001, t=-7.815 and t=-5.010, respectively). It is noteworthy to highlight the strong correlation found between OPs power and the amplitude (r=.75) as well as the implicit time (r=.75) of the b-wave in the XLRS group, whereas a strong correlation is lacking in the control group.
Conclusions :
The transmission of information in patients with XLRS differs due to the presence of neuroretinal splitting in the central macula. The significant OPs reduction in XLRS individuals and their association with the b-wave imply a reorganization of the information transfer across retinal layers.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.