Observational Study to Investigate the Short-term Effects of Transcorneal Electrical Stimulation on Visual Performance

This open-label observational study includes patients with retinitis pigmentosa or similar degenerative diseases (e.g. Usher syndrome, cone rod dystrophy) who already use the OkuStim System and are experiencing short-term effects following treatment.

Study procedure:

Participants will complete a questionnaire on previous experiences with short-term effects following transcorneal electrical stimulation therapy with the OkuStim System. If eligible, baseline ophthalmologic examinations will be performed, including slit-lamp examination, best-corrected visual acuity (BCVA), quick contrast sensitivity function (qCSF), kinetic perimetry, and microperimetry. Participants will then receive TES treatment with the OkuStim System according to the prescribed stimulation parameters for 30 minutes. Following treatment, examinations on BCVA and qCSF will be repeated. After a break of approx. 3.5 hours, participants will complete a second questionnaire assessing currently perceived changes in visual performance. Final examinations will be performed, including BCVA, qCSF, and microperimetry.

This scientific study aims to contribute to a better understanding of the underlying mechanisms of TES.

• Transcorneal Electrical Stimulation using the OkuStim System (Device), also known as OkuStim: Single application of the OkuStim® System for TES therapy in accordance with its intended purpose for 30 minutes. No control or comparative intervention planned.

Primary outcomes

• Best-corrected visual acuity [- ETDRS: Baseline and approx. 3.5 hours after TES - Manifold Platform: Baseline, immediately after TES, and approx. 3.5 hours after TES]: Measured with ETDRS chart and Manifold Platform
• Contrast sensitivity [Baseline, immediately after TES, and approx. 3.5 hours after TES]: Quick contrast sensitivity function (qCSF) measured with Manifold Platform
• Retinal sensitivity [Baseline and approx. 3.5 hours after TES]: Measured with microperimetry
• Subjective changes in visual performance [Approx. 3.5 hours after TES]: Questionnaire on perceived changes in visual performance after TES therapy

Other outcomes

• Safety [3.5 hours after TES]: Number and nature of device-related adverse events and serious adverse events

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Adult patients (≥ 18 years) with clinically diagnosed retinitis pigmentosa (RP) or other similar degenerative retinal disease
* Current treatment with TES using the OkuStim® System within the intended purpose
* Subjective perception of short-term effects after TES treatment
* Ability and willingness to give informed consent

Exclusion Criteria:

* Cognitive, psychological, or linguistic limitations that prevent informed consent or proper study participation
* Presence of other eye diseases (e.g., cataract, glaucoma, macular degeneration) that, in the opinion of the investigator, compromise or confound study assessments
* Simultaneous participation in other clinical studies that could influence the results of the study
* Severe comorbidities that could compromise patient safety or study conduct

• Dr. med. Svenja Deuchler, Principal investigator, Augenzentrum Frankfurt Prof. Koch GmbH