Retinal neurovascular responses to transcorneal electrical stimulation measured with optical coherence tomography

Abstract

Noninvasive transcorneal electrical stimulation (TES) has emerged as a potential strategy to facilitate visual restoration and promote retinal cell survival for certain retinal and optic nerve diseases owing to its neuroprotective effects. However, the neurovascular responses of retinal neurons evoked by TES have not been completely determined. To investigate this issue, we utilized a custom-designed spectral-domain optical coherence tomography (SD-OCT) to record the retinal neural and vascular responses under TES in vivo simultaneously. Significant increases of both positive and negative intrinsic optical signal (IOS) changes were recorded in all three segmented retinal layers, which mainly related to neural activities. However, the changes of TES-induced retinal vascular responses, including blood velocity, cross-sectional area of vessel, and blood flow, were not significant. It suggests that TES mainly elicited neural responses in retina, while no significant vascular responses were evoked. Our results provide experimental evidence to the mechanism of retinal neurovascular coupling under TES. Additionally, the present study also suggests that SD-OCT could be utilized as a promoting method to explore neurovascular responses under retinal stimulation in clinical treatment and technology. Impact statement Noninvasive transcorneal electrical stimulation (TES) has emerged as an effective treatment for certain retinal and optic nerve diseases owing to its neuroprotective effects. However, the retinal neurovascular responses evoked by TES have not been completely determined. To investigate this issue, we utilized a custom-designed spectral-domain optical coherence tomography (SD-OCT) to record the retinal neural and vascular responses evoked by TES in vivo simultaneously. The present study suggested that TES mainly elicited neural responses in retina, while no significant vascular responses were evoked. Our results provide experimental evidence to the mechanism of retinal neurovascular coupling evoked by TES. Additionally, the present study also suggests that SD-OCT could be utilized as a promoting method to explore neurovascular responses under retinal electrical stimulation.

OCT-measured retinal vasculature and intrinsic optical responses to transcorneal electrical stimulation

“…IOS is defined as the change in intrinsic optical properties after being stimulated, which can be defined as ∆I/I (where ∆I represents change in signal replication caused by the stimulus [36,37], and I represents the signal amplitude before the stimulus). Firstly, B-scan images obtained at the same location were reconstructed and registered, Ten consecutive measurements of the same location were then averaged and the signal-noise-rate(SNR) was thus increased.…”

Fabrication and Characterization of a Flexible Thin-Film-Based Array of Microelectrodes for Corneal Electrical Stimulation

“…Both approaches have demonstrated protection effects on the retinal ganglion cells (RGCs) and on the photoreceptors preserved from degeneration processes. This protection mechanism may be due to the increase in certain bioactive factors, for example, insulin-like growth factor 1 (IGF-1), brain-derived neurotrophic factor (BDNF), and ciliary neurotrophic factor (CNTF) [6,[13][14][15][16][17][18][19].…”

Biomedical optical imaging technology and applications: From basic research toward clinical diagnosis

“…Su et al. 70 reported their investigations on retinal neurovascular responses to transcorneal electrical stimulation (TES). By using SD-OCT to measure the intrinsic optical signal (IOS) and the blood flow parameters, they were able to record simultaneously the neural and vascular responses of the retina to TES in vivo.…”