Transcorneal electrical stimulation for the treatment of retinitis pigmentosa: results from the TESOLAUK trial

Abstract

ObjectiveTo explore the impact of weekly transcorneal electrical stimulation (TES) over a 6-month period as a treatment for retinitis pigmentosa (RP).Methods and analysisA prospective open-label observational trial was carried out assessing weekly TES in participants with RP for a period of 6 months followed by observation for a further 6 months. Clinical examination and investigations were carried out at 3 monthly intervals for a total of 12 months. The primary outcome measure explored safety through a descriptive analysis of adverse effects with secondary outcome measures evaluating structural and functional efficacy.ResultsSeven male and seven female participants with RP aged 18–80 years were recruited. TES was well tolerated with no serious adverse events reported. Two participants reported transient foreign body sensation and one participant had discomfort underneath the skin electrode. Following 6 months of TES, best-corrected visual acuity increased by 1.1±1.4 letters in the control arm and 0.93±1.4 letters in the treated arm. Central microperimetry threshold sensitivity rose by 0.02±0.5 decibels (dB) and 0.37±0.4 dB and Goldmann visual field volume by 0.16±0.09 steradians (sr) vs 0.22±0.12 sr for the control and treated eye, respectively. There was no statistical significance seen between eyes following the treatment or observation period.ConclusionThis small open-label clinical trial showed that TES was safe and well tolerated in patients with RP. Visual function measurements at 6 months demonstrated no significant difference between the control and treated eyes. The results justify a larger clinical trial over a longer period of time in order to identify any treatment effect.

Clinical Trial to Evaluate Safety and Efficacy of Transdermal Electrical Stimulation on Visual Functions of Patients with Retinitis Pigmentosa

“…Recently, two groups reported that they did not detected significant improvements of the visual acuity and visual field after 1 year of transcorneal electrical stimulation in patients with retinitis pigmentosa 12,19 . They determined the stimulation current intensity based on individual electrical phosphene threshold.…”

Removal of the Sinusoidal Transorbital Alternating Current Stimulation Artifact From Simultaneous EEG Recordings: Effects of Simple Moving Average Parameters

“…A recent pilot clinical study shows similar effectiveness of long-term treatment (i.e., 4–6 years) with transcorneal(tco)ACS ( Ota et al, 2018 ). Moreover, tcoACS has also proven to be useful in the treatment of retinitis pigmentosa, wherein recent clinical studies in humans demonstrate both structural and functional improvement ( Schatz et al, 2011 ; Bittner and Seger, 2018 ; Bittner et al, 2018 , however, see Wagner et al, 2017 ). Several other clinical studies demonstrate that tcoACS can improve visual function (i.e., visual acuity and/or visual field) in patients with various retinal diseases, including retinal artery occlusion, traumatic optic neuropathy, non-arteritic ischemic optic neuropathy, and Best vitelliform macular dystrophy (for a review, see Ota et al, 2018 ).…”

The Use of Electrotherapeutics in Ophthalmology

“…His works on electrical stimulation provided inspiration for the development of TES. 9,10 IONTOPHORESIS: In 1908, Robert Wirtz was the first to use iontophoresis to treat ocular diseases. Iontophoresis is the use of electrical current to drive ionically charged medications into the body.…”

“…Electric stimulation of the cornea, lens, choroid, and retina have proved efficacious for the development of devices such as iontophoresis, transcorneal electrical stimulation (TES), the Argus II epiretinal implant (Second Sight Retinal Products, Lausanne, Switzerland), and the Alpha AMS subretinal implant (Retina Implant AG, Reutlingen, Germany). [8][9][10][11] This perspective looks at the various electrotherapeutics recognized by Edward Jackson and discusses the electrical devices that are being used or developed in contemporary practice.…”