Electrotherapeutic device/protocol design considerations for visual disease applications

Abstract

One of the more interesting applications of electrotherapy involves its use in the treatment of visual disease; including retinitis pigmentosa, diabetic retinopathy and macular degeneration. The therapeutic efficacy of electrotherapy is highly dependent upon the incorporation of appropriate design choices for both the electrotherapeutic device and treatment protocol. Electrotherapeutic design drivers include electrode probe-tissue interface, device reliability, operational constraints, treatment protocol procedures, and safety. In FDA guided and FDA supervised clinical studies (FDA pre-IDE numbers 1980275 and 1000038 and FDA IDE number G020106) involving electrotherapeutic intervention for dry macular degeneration, 61% of a 400 patient cohort treated with electrotherapy achieved visual acuity improvements of two lines or more on the Snellen chart. Average electric current intensities in the range of 60 to 125 muA were utilized to achieve this level of therapeutic efficacy. With further improvements in the design of electrotherapeutic device waveforms, frequency selection, treatment protocols and electrode probe configurations; long-term visual acuity improvements of two lines or better on the Snellen chart can be anticipated for more than 60% of the patients who are in the early stages of retinitis pigmentosa, diabetic retinopathy and dry macular degeneration.

Noninvasive Electrical Stimulation Improves Photoreceptor Survival and Retinal Function in Mice with Inherited Photoreceptor Degeneration

“…Mice were stimulated by a TheraMac ES device (Acuity Medical, Annapolis, MD, USA), which was selected for the study because of an earlier report implicating potential benefit of the device in human patients with AMD. 10,13,14 To further explore the protective effect of noninvasive ES on mouse photoreceptors, the portable electrode probe of this ES device was placed on four spots of the skin around the mouse orbit-two on the upper eyelid and two on the lower eyelid, for 40 seconds per spot. ES was generated as a series of positive monophasic rectangular pulse trains, followed by a series of negative monophasic rectangular pulse trains, both at increasing frequencies from 2 pulls per second (PPS) to 200 PPS (Fig.…”

“…7,8 The protective effects of minimal or noninvasive ES have since been reported in patients with AMD, RP, and retinal artery occlusion. 6,[9][10][11][12][13]14 Importantly, no significant safety-related adverse effects were observed in any of these studies; however, due to the lack of standardization of ES parameters in clinical trials and animal studies, the effects of ES have often been inconsistent or even controversial. 15 To date, it is not yet known why or how ES improves vision.…”

A review of textile-based electrodes developed for electrostimulation

“…Electrotherapy or electrostimulation includes various therapeutic approaches related to orthopedic injuries and diseases whereby a low-level current is introduced into the human body to stimulate and activate muscles or nerves. 1–3 It enables muscles to be exercised without the usual neurostimulation or to suppress pain sensations. 4–7 Different modalities of electrotherapy can be distinguished depending on the chosen stimulation parameters and the planned outcome.…”