Retinitis pigmentosa (RP) is a progressive degenerative disease of the retina, which often leads to blindness. 1 in 4000 people in the UK are affected by RP yet there is no established therapy for treating or delaying its progression.

Transcorneal electrical stimulation (TES) has garnered attention as a possible therapeutic option for RP. Research has shown that TES improves retinal cell viability and visual function. An initial pilot study of TES on 24 participants with RP demonstrated that it was safe and improved vision.

This study aims to confirm the safety of the new CE-approved Okustim device and to further characterise the benefits of TES on a larger scale. 12 participants will be enrolled for 1 year across two sites in the UK - the Oxford Eye Hospital and London Moorfields Eye Hospital.

Recruited participants will undergo weekly TES of 1 eye for 30 minutes for a period of 6 months. This will be followed by a further 6 months of observation without stimulation giving a total participation time of 1 year. Participants will be assessed at 3, 6, 9 and 12 months after their initial baseline visit by clinical examination, investigations and questionnaires.

Participants should have a diagnosis of RP and be capable of giving consent. Participants, or a carer, should have sufficient motor skills to attach the device themselves. As this study seeks to ascertain the impact of TES on RP, participants with other eye diseases (e.g. diabetic retinopathy) cannot be included in the study.

Inclusion Criteria:

• Participant is willing and able to give informed consent for participation in the study
• Male or Female, 18 or more years of age
• Diagnosis of retinitis pigmentosa (rod-cone dystrophy) made by an ophthalmologist
• Participants should have a visual acuity of ≥ 0.02 (Snellen Chart)
• Able (in the investigators opinion) and willing to comply with all study requirements
• Willing to allow his or her General Practitioner and consultant, if appropriate, to be notified of participation in the study
• Participants, or a designated other, should have sufficient motor skills (assessed by the investigator) to apply the device independently

Exclusion Criteria:

• Female participants who are pregnant, lactating or planning pregnancy during the course of the study
• Diabetic Retinopathy
• Previous arterial or venous occlusion of the retina
• Previous retinal detachment
• Previous silicone oil tamponade
• Dry or exudative age-related macular degeneration
• Macular oedema
• All forms of glaucoma
• Any form of corneal degeneration that reduces visual acuity
• Neovascularisation of any origin
• Any other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the study, or may influence the result of the study, or the participant's ability to participate in the study
• Forms of mental illness related to bipolar affective and schizoid-affective disorders, and all forms of dementia
• Simultaneous participation in another interventional study or history of interventions where effects may still persist