Purchase this article with an account.
Carla J Abbott, David AX Nayagam, Owen Burns, Helen Feng, Ceara McGowan, Robyn H Guymer, Chris E Williams, Penelope J Allen, Chi D Luu; Effect of chronic electrical stimulation with a fully implantable electrode on photoreceptor survival in a retinal degeneration model. Invest. Ophthalmol. Vis. Sci. 2019;60(9):4992. doi: https://doi.org/.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Chronic electrical stimulation is known to have a neuroprotective effect on retinal cells. Most previous studies have used a transcorneal stimulation approach, requiring electrodes to be positioned on the cornea, which may affect patient compliance and can cause dry eye and corneal irritation. As an alternative solution, retinal prosthesis research has shown that implantable electrode arrays are safe and stable over time. The aim was to determine if chronic low-level electrical stimulation with a fully-implantable electrode preserves retinal function in a transgenic model of retinal degeneration.
P23H-3 retinal degeneration rats were divided into 3 groups of control (n = 6), passive (n = 6) and active stimulation (n = 7). Animals in the passive and active stimulation groups had a platinum electrode implanted in one eye of each animal at 7 weeks of age. Animals in the passive group did not receive the stimulation. Animals in the active stimulation group received 1 hour of chronic micro-electrical stimulation (100μA, 1Hz) twice per week for 4 weeks. Full-field electroretinography (ERG) was performed at 6- (baseline) and 12- (post-treatment) weeks of age as a surrogate measure of photoreceptor survival. The ERG responses of the 3 study groups were compared to determine the effect of electrical stimulation on photoreceptor survival.
In the active stimulation group, the ERG a-wave response amplitude at 12 weeks of age was slightly reduced in the stimulated eyes (83.8 ± 38.1, p=0.413) but markedly reduced in the non-stimulated fellow eyes (33.7 ± 19.7, p<0.001), compared to the baseline value at 6 weeks of age (100.3 ± 29.9). The ERG a-wave amplitude of both eyes in the control and passive groups were markedly reduced at 12 weeks of age compared to the baseline value (p<0.001). Furthermore, the magnitude of ERG a-wave amplitude reduction in the control and passive groups was similar to that of the non-stimulated fellow eyes of the active stimulation group.
Chronic low-level electrical stimulation using a fully implanted electrode preserved photoreceptor function in the P23H-3 rat model of retinal degeneration. A fully implantable electrode has the potential to improve compliance and reduce side effects of the transcorneal stimulation approach and should be investigated further.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
This PDF is available to Subscribers Only