Transcorneal electrical stimulation for the treatment of retinitis pigmentosa - a multicenter safety study of the OkuStim® System (TESOLA-study).

Background: Transcorneal electrical stimulation (TES) has been suggested as a possible treatment for retinitis pigmentosa (RP). Objective: To expand the safety assessment of repeated applications of an electrical current from a DTL-like electrode in patients with RP. Methods: This single-arm open label interventional safety trial included a total of 105 RP patients from 11 European centers, who received weekly TES for 6 months on 1 eye followed by observation for another 6 months without stimulation. The primary outcome measure was safety, indicated by the frequency and severity of adverse events. Secondary measures included intraocular pressure and central retinal thickness. Visual field and visual acuity were examined using the methods available at each site. Results: Dry eye sensation was the most common adverse event recorded (37.5%). Serious adverse events secondary to TES were not observed. Most adverse events were mild and all resolved without sequelae. The secondary outcome measures revealed no significant or clinically relevant changes. Conclusion: The present results confirm the excellent safety profile of TES. Transient dry eye symptoms were the most common adverse event.