Abstract
Purpose :
We previously reported that stimulation efficiency of retinal prosthesis decreases during suprachoroidal-translationally applied trains of stimulus pulses at the frequency of 20 Hz [Y. Nakano, et al. IOVS 2020;61:2210]. To understand the underlying mechanism that led to the decrease, we have investigated how inter-pulse interval (IPI) affects electrical stimulation efficiency in acute animal experiments.
Methods :
Field potentials were recorded from the right superior colliculus of healthy adult rats (Long-Evans, n = 7) anesthetized with urethane. Paired-pulse trans-retinal electrical stimulation (TES) at an IPI of 20-200 ms was focally delivered to the sclera of the left eyeball. Each pulse was cathodic-first biphasic, with no gap term (Fig. 1). The amplitudes of evoked potentials (EPs) to the second TES pulse were compared with those to the first one.
Results :
The second EPs were significantly suppressed (p <0.05, paired t-test) by 35% of the first EPs at 60 ms and 80% at 100 ms, of IPI. The relative amplitude of the second EP to the first, recovered at 200 ms, is shown in Fig. 2.
Conclusions :
In this study, the length of IPI affected the EP of the second pulse. In the future, we will investigate the IPI that can minimize the decrease in EP after the second pulse, during continuous stimulation.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.