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

Retinitis pigmentosa and similar degenerative diseases of the retina lead to progressive loss of vision. TES therapy with the CE-marked OkuStim® System is a treatment approved in the EU for slowing the progression of the disease. Patients increasingly report short-term subjective improvements in vision, which have not yet been systematically investigated. This exploratory study is conducted to determine whether these subjective short-term effects can be measured, and therefore also be quantified, by objective tests.

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.

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