Transcorneal Electrical Stimulation for the Treatment of Visual Field Defects in Patients With Open-Angle Glaucoma (TES-GPS)

Transcorneal Electrical Stimulation for the Treatment of Visual Field Defects in Patients With Open-Angle Glaucoma - a Monocentric, Randomized, Double-Masked, Sham-Controlled Pilot Study

Glaucoma is a progressive optic neuropathy with retinal ganglion cell loss which leads to visual field loss. Open-angle glaucoma is the most common form of glaucoma.

The aim of this pilot study is to evaluate the safety and effectiveness of the treatment of visual field defects using transcorneal electrical stimulation (TES) with the OkuStim 2 System in patients with primary open-angle glaucoma, pseudoexfoliation glaucoma, pigment dispersion glaucoma or normal tension glaucoma.

Study Overview

• Status: Recruiting
• Conditions: Primary Open Angle Glaucoma; Glaucoma; Pseudoexfoliation Glaucoma; Normal Tension Glaucoma; Pigment Dispersion Glaucoma
• Intervention / Treatment: Device: Transcorneal electrical stimulation (TES) with the OkuStim 2 System

Detailed Description

Electrical stimulation therapy with the OkuStim System can help patients with retinitis pigmentosa and other hereditary retinal diseases slow the progression of visual field defects and thus preserve usable vision for longer. Since degenerative processes in the retina also lead to loss of vision in patients with glaucoma, the desired clinical benefit in this group of patients is also to slow down the decline in the visual field.

This is a prospective, single-center, randomized, sham-controlled, double-masked pilot study in a parallel group design. Patients are assigned 1:1 to one of two different groups: Sham group (sham treatment) or TES with maximum tolerated current intensity below the pain threshold (tolerance threshold). Patients are stimulated in one eye (study eye). Since these are patients with progressive visual field defects and the experimental therapy is being compared with a sham treatment, the patients also receive pressure-lowering eye drops ("treatment as usual", "TAU") to ensure the safety of the study participant. Treatment duration is 18 months for each patient, with application of TES once a week for 30min.

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Katrin Lorenz, Prof.; Phone Number: +49 6131 174069; Email: katrin.lorenz@unimedizin-mainz.de

Study Locations

• Germany
  • Mainz, Germany, 55131
    • Recruiting
    • Augenklinik und Poliklinik der Universitätsmedizin Mainz, Johannes Gutenberg-Universität Mainz
    • Contact: Katrin Lorenz, Prof.; Phone Number: +49 6131 173612; Email: klinisches-studienzentrum-augenklinik@unimedizin-mainz.de

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Willingness to participate in the study, the subjects signed and dated informed consent must be submitted before the start of the screening
2. Age ≥ 40 years
3. Primary open-angle glaucoma, pseudoexfoliation glaucoma, pigment dispersion glaucoma or normal tension glaucoma (according to the EGS criteria) in the study eye
4. Current progression in perimetry of at least 1.5 dB per year in the study eye and mean defect (MD) in the study eye between ≥ 6 and ≤ 12 dB (Octopus visual field) or ≤ -6 and ≥ -12 dB (Humphrey visual field) in the screening examination as the mean value of the two visual field examinations carried out as part of the screening (permitted deviation maximum 2 dB)
5. Visual acuity ≥ 0.2 decimal in the study eye (corresponds to a visual acuity of 0.7 logMAR)
6. The patient must master home stimulation after extensive training.
7. Ability of subject to understand the scope, significance and individual consequences of participation in the study
8. Ability of subject to give consent
9. If both eyes meet the inclusion/exclusion criteria, the eye with the higher MD is selected as the study eye. If the MD is the same in both eyes, the eye with the worse visual acuity will be selected as the study eye. If there is no difference between the eyes, the right eye will be selected as the study eye
10. Negative serum or urine pregnancy test at screening in women of childbearing potential. Participants are considered to be of nonchildbearing potential if they are postmenopausal and have not menstruated for at least 12 months prior to screening or if they are surgically sterile
11. Women of childbearing potential must agree to be abstinent or to use highly effective methods of contraception that result in a failure rate of less than 1% per year. This applies consistently throughout the duration of the treatment once you have given your consent to participate in the study.

Exclusion Criteria:

1. Neovascularisations of any origin in the study eye
2. Condition after arterial or venous occlusions in the study eye
3. Condition after intraocular surgery in the last 3 months before the screening examination in the study eye
4. Acute (intra)ocular inflammation in any eye
5. Non-proliferative or proliferative diabetic retinopathy in the study eye
6. Condition after retinal detachment in the study eye
7. Dry age-related macular degeneration affecting the visual field in the study eye
8. Exsudative age-related macular degeneration in the study eye
9. Macular edema of any origin in the study eye
10. Other relevant retinal diseases in the study eye
11. Any form of corneal degeneration that limits vision in the study eye
12. Any disease other than glaucoma affecting the central 30° visual field in the study eye
13. No cataract surgery or other eye surgery may be planned for the patient in the study eye during the duration of the study (except laser trabeculoplasty)
14. Patients with active implants
15. General illnesses that are difficult to control/adjust and which, in the opinion of the investigator, could jeopardize regular study routines
16. Poor general condition according to the investigators assessment
17. Mental illness or dementia, that, in the opinion of the investigator, reduces the understanding of the study procedures and use of the Okustim 2 System
18. Simultaneous participation in another interventional study or past interventions whose effect may still be ongoing (30 days)
19. Breastfeeding women
20. Patients unable to consent
21. Previous enrolment in the TES-GPS study
22. Contraindications to the use of OkuStim 2 such as allergies/hypersensitivity to silver

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Sham Comparator: Sham group; 0µA to therapy amplitude, ramping up in 30 seconds; directly followed by 0µA stimulation for 30 minutes. Stimulation will be performed once per week, for 30 minutes, for 18 months.	Device: Transcorneal electrical stimulation (TES) with the OkuStim 2 System; Retinal stimulation is achieved through transcorneal current application: using a thread electrode, a weak current (≤ 1mA) is introduced onto the surface of the eye, which spreads through the eye towards the retina.; Other Names: OkuStim; OkuStim 2 System; OkuStim System
Experimental: TES group; 0µA to therapy amplitude, ramping up in 30 seconds; directly followed by stimulation with the therapy amplitude for 30 minutes. Stimulation will be performed once per week, for 30 minutes, for 18 months.	Device: Transcorneal electrical stimulation (TES) with the OkuStim 2 System; Retinal stimulation is achieved through transcorneal current application: using a thread electrode, a weak current (≤ 1mA) is introduced onto the surface of the eye, which spreads through the eye towards the retina.; Other Names: OkuStim; OkuStim 2 System; OkuStim System

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Difference in Humphrey visual field examination between the TES-treated group and the sham-treated group	18 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Visual field - Changes in the average in the Mean Deviation		6/12/18 months
Visual field - Changes in local visual field defects in at least 3 positions		18 months
Visual acuity	Visual acuity measurements will be done using the 4 meter Early Treatment Diabetic Retinopathy Study (ETDRS) protocol.	18 months
Intraocular pressure		18 months
OCT	GCL-OCT (macular cube), thickness	18 months
OCT	OCT optic nerve (RNFL), thickness	18 months
Flavoprotein fluorescence	Flavoprotein fluorescence (FPF) will be measured with the OcuMet Beacon. FPF will be reported both by intensity (a cumulative value reflecting global signal strength), and heterogeneity (measures variation of the relative intensity across the image).	18 months
NEI-VFQ-25	Original numeric values from the survey are converted to a 0 to 100 scale (scores represent the achieved percentage of the total possible score). To calculate an overall composite score for the VFQ-25, the vision-targeted subscale scores are averaged.	18 months
Additional antiglaucoma therapies	Comparison between groups regarding additional antiglaucomatous therapies (nature and number of e.g. eye drops, surgery, laser treatments)	18 months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Safety	Safety endpoints are the long-term safety of the device, its tolerability assessed by adverse events and the use of rescue treatments.	18 months

Collaborators and Investigators

• Sponsor: Okuvision GmbH
• Collaborators: Interdisciplinary Center for Clinical Trials, University Medical Center Mainz; University Medical Center of the Johannes Gutenberg University Mainz, Department of Ophthalmology; Sponsored by the German Federal Ministry of Education and Research (FKZ 13GW0732A)
• Investigators: Principal Investigator: Katrin Lorenz, Prof., Augenklinik und Poliklinik der Universitätsmedizin Mainz, Johannes Gutenberg-Universität Mainz

Publications and helpful links

General Publications

• Lorenz K, Schuster A, Michel HM, Ruckes C, Kronfeld K, Schippert R, Stett A, Beck A. Transcorneal electrical stimulation for the treatment of visual field defects in patients with open-angle glaucoma: a monocentric, randomised, double-masked, sham-controlled pilot study: the TES-GPS study protocol. BMJ Open. 2026 Feb 9;16(2):e112879. doi: 10.1136/bmjopen-2025-112879.

Study record dates

Study Major Dates

• Study Start (Actual): April 2, 2025
• Primary Completion (Estimated): June 1, 2028
• Study Completion (Estimated): June 1, 2028

Study Registration Dates

• First Submitted: November 4, 2024
• First Submitted That Met QC Criteria: November 8, 2024
• First Posted (Actual): November 12, 2024

Study Record Updates

• Last Update Posted (Actual): March 12, 2026
• Last Update Submitted That Met QC Criteria: March 10, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: POAG; Glaucoma; Electrical Stimulation; TES; TcES; OkuStim; Okuvision
• Additional Relevant MeSH Terms: Eye Diseases; Optic Nerve Diseases; Uveal Diseases; Ocular Hypertension; Iris Diseases; Glaucoma; Glaucoma, Open-Angle; Low Tension Glaucoma; Exfoliation Syndrome
• Other Study ID Numbers: TES-GPS; CIV-24-02-045997 (Other Identifier: EUDAMED)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No