Abstract
Purpose :
Oscillatory Potentials (OPs) of mixed full-field electroretinogram (ERG) mesopic response, whose origin is still debated, are fast high-frequency wavelets arising from the a-wave to the b-wave, thought to be driven in humans predominantly by cones. We investigate the occurrence of OPs in two congenital stationary dysfunctional cone syndromes – achromatopsia (ACHM) and blue-cone monochromacy (BCM). The aim of the study was to examine whether S-cones, present in BCM but not in ACHM, play a role in the generation of the OPs and their relationship with age, factor that could possibly explain the presence of a disease progression.
Methods :
We analyzed 39 ACHM (mean age 35.6, ±11) 19 BCM (mean age 36.5, ± 18) patients and 26 (mean age 40.1 ± 11) controls. Full-field ERG (ColorDome, Espion E2/E3, Diagnosys) was used to record the mixed cone-rod signal in mesopic condition at 3 cd.s/m2, and OPs were extracted by filtering the traces between 70 and 300Hz. Subsequently, time-frequency analysis was performed by convolving a complex Morlet wavelet to extract OPs power (dB). One-way ANOVA analysis and Spearman’s R correlation were computed to assess the relationship between OPs and age. Tukey HSD post-hoc test was used to correct for multiple comparisons.
Results :
OPs power is significantly reduced in both ACHM and BCM groups compared to the control group [F(2) = 36.60, p<.001] and no significant differences were found between ACHM and BCM [Figure 1]. A negative correlation with age has been found in all three groups, although the significance has been reached just by BCM group (NORM: R(24)= -.24, p =.23; ACHM: R(38)= -.23, p =.14; BCM: R(18)= -.54, p=.016) [Figure 2].
Conclusions :
Results demonstrate that fully functioning S-cones present in the BCM group do not influence the generation of OPs. The significant correlation between age and OP was found only in the BCM group, probably not reflecting the disease progression, but the natural aging of the retina as very similar trend was also found in all groups. To some extent, OPs could be used as a biomarker of the connectivity between outer and inner retina. Thus, in the age range explored, variations of OP appear to be extremely small, indicating that, beyond the normal aging process, the outer and inner retinal connectivity in ACHMs and BCMs is relatively stationary.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.