Transcorneal electrical stimulation for patients with retinitis pigmentosa – Safety and efficacy evidence from a multicentric observation study – TESOLA

Abstract

Purpose : The multicentric observational study was performed to verify the safety and efficacy of transcorneal electrical stimulation (TES) in a large number of patients with retinitis pigmentosa (RP).

Methods : 105 patients (mean age 46 ± 15.9; 58 males) underwent TES (5-ms biphasic pulses@20 Hz, 30 minutes/week for 6 months) using the OkuStim®-system (Okuvision GmbH, Germany) and finished the study per protocol. All patients were stimulated in one eye with 150% stimulation current of their individual electrical phosphene threshold. Patients were stimulated at home after a 4-week training in the clinic (n=32) or in the clinic (n=73). Primary outcome was safety; secondary endpoints were efficacy measurements via visual field and visual acuity; additional intraocular pressure (IOP) and optical coherence tomography (OCT) were performed. Patients were examined at baseline (week 1), during weeks 12, and 24 (stimulation) as well as weeks 36 and 48 (follow up examinations during stimulation free period).

Results : 97 patients completed the study per protocol. Most adverse events (AE) were dry eye symptoms reported by patients (37.5% of all AE). No serious AEs related to the treatment were observed; no serious AEs related to the treatment were reported during the follow up examinations. The efficacy analyses revealed significant improvement in the BCVA in the stimulated eye (MANOVA; p < 0.05), while no changes were observed in the fellow eye (MANOVA; p > 0.05). Moreover positive trend showing improvements in the visual fields of the stimulated eye as compared to the fellow eye was observed (Ranks test; p = 0.084). No significant effect on IOP or OCT were observed during stimulation.

Conclusions : TES was found to be safe; AEs were mainly dry eye symptoms treatable by artificial tears. Significant improvements in visual acuity and the positive tendency in visual fields observed in the stimulated eyes demonstrate the efficacy of TES in RP patients. The majority of patients reported to be satisfied with the therapy.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.