Research and Clinical Trials on Retinitis Pigmentosa (RP)

This page brings together current research on retinitis pigmentosa — from genetics and disease progression parameters to clinical data on TES with OkuStim®.

Why researchis essential

Retinitis pigmentosa (RP) is a hereditary retinal disease that can lead to vision loss over years. Research helps to understand disease mechanisms, measure progression, and evaluate treatment options—with tangible benefits for patients, families, and the healthcare system. Reviews describe not only the medical but also the economic and psychosocial impacts of RP. Typical for RP: night blindness in early stages, later constriction of the visual field leading to “tunnel vision”—this clinical development is well documented and helps to select meaningful study endpoints. Conclusion: Research is the foundation for realistic expectations and better care decisions.¹

Genetics & Inheritance—Fundamentals

RP has pronounced genetic diversity: reviews describe mutation-caused forms in ≥80 genes; inheritance is predominantly autosomal recessive (~20%), autosomal dominant (10–20%), or X-linked (~10%), with sporadic cases also occurring. Genetic diagnosis provides important information for counseling, study eligibility, and —for suitable subtypes— targeted therapies.²

Therapeutic Approaches
in Research

International literature describes several approaches:

Gene therapy: For RPE65-associated hereditary retinal dystrophies, an approved gene therapy exists (voretigene neparvovec); guidelines and assessment documents confirm clinical benefit with appropriate patient selection.¹
Cell-based approaches: The goal is to regenerate or stabilize damaged retinal areas in the future (currently predominantly in studies).¹
Optogenetics & retinal implants: Concepts for reactivating remaining retinal circuits and supplementing function in advanced stages—also primarily in the study context.¹

Why do studies often measure the visual field? In RP, peripheral vision is particularly affected. The area of the retina with intact photoreceptors (VFA, visual field area) decreases exponentially over time. Studies report annual decline rates (ADR) of approximately 5–17%, depending on the measurement method.²

Clinical Trials on TES Therapy with OkuStim®

Transcorneal electrical stimulation (TES) is a noninvasive stimulation of the ocular surface with weak alternating currents. The goal is to activate cellular protective mechanisms of the retina and thereby preserve function longer. In an interventional randomized 12-month study (weekly application, one eye treated), visual field area loss was lower in treated eyes— and the effect showed dose dependence (higher current intensity, greater benefit).²

Safety: In the published analysis, adverse events were predominantly mild and transient, most commonly dry eyes, which improved rapidly with tear substitutes; a current-intensity-dependent increase in serious adverse events was not observed.²

Important: TES does not cure RP. However, studies have shown that TES can slow visual field loss. Whether TES is suitable for you should be discussed with your treating physician.²

What does this mean for patients?

Set realistic expectations: RP progression is heterogeneous. The visual field decreases on average by approximately 5–17% annually—individual courses may vary. Comparable measurements (same method/setting) are crucial.²
Check genetics: A genetic test can open therapy and study pathways and helps with family counseling.¹
Actively strengthen quality of life: Research shows significant daily life and participation burdens (mobility, work, mental health). Rehabilitation, assistive devices, and counseling are therefore advisable early on.¹
Know specific options: For RPE65 mutations, gene therapy may be an option; for many other forms, clinical studies are important.¹