Retinitis Pigmentosa
Conditions
Keywords
Transcorneal electrostimulation, TcES, TES
Brief summary
The purpose of this study is to determine the long-term effects of transcorneal electrostimulation (TcES) in patients with retinitis pigmentosa (RP). In a prior study (NCT00804102) the results of short-term stimulation showed a positive effect on the visual field and other parameters. In this study, the patients will be stimulated with either 0%, 150% or 200% of the individually determined phosphene threshold.
Detailed description
The study was performed at the Centre for Ophthalmology, University of Tübingen, Germany. The protocol was approved by the local ethics committee. All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008. Informed consent was obtained from all patients for being included in the study. The study was conducted according to the standards of GCP, the European Union Directive for Medical Devices, and the German Medical Product Law. Patients were seen at 14 visits over a period of 78 weeks: one baseline visit (screening), followed by 12 visits (in week 1-4 weekly, then in weeks 10, 16, 22, 28, 34, 40, 46 and 52; dates varied a maximum of ± 1 week) including application of TcES for 52 weeks and one follow-up visit (in week 78, dates varied a maximum of ± 1 week). After inclusion patients were randomly assigned to TcES with 0 mA (sham), 150% or 200% of their individual electrical phosphene threshold (EPT) current at 20 Hz. Patients and technicians who performed kinetic perimetry, as well as full-field electrophysiology (ERG), multifocal ERG (mfERG) and dark adaptation, were blinded to the treatment group for the entire study period. The physicians who performed all other examinations and TcES were not blinded to study treatment because they were responsible for setting the stimulation parameters.
Interventions
Sponsors
Okuvision GmbH
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* Adult subject with RP (rod-cone dystrophy) * BCVA 0.02 to 0.9 * Reliable visual field measurements * Reliable ERG measurements * Skillful enough to use the device at home * Able to give consent and take part during the whole study
Exclusion criteria
* Diabetic retinopathy * Neovascularisation of any origin * After arterial or venous occlusion * After retinal detachment * Silicone oil tamponade * Dry or exudative age-related macular degeneration * Macular edema * All forms of glaucoma * Any form of corneal degeneration that reduces visual acuity * Systemic diseases that are difficult to control or manage, that could endanger the normal study schedule * Patients in a permanently poor general condition, which could hinder the regular attendance at control examinations in the clinic * Forms of mental illness related to the bipolar affective and schizoid-affective disorders, and all forms of dementia * Simultaneous participation in another interventional study or history of interventions whose effect may still persist
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Visual Field, III4e | one year | Change in the area measured by kinetic visual field measurement |
| Visual Field, V4e | one year | Change in the area measured by kinetic visual field measurement |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| BCVA | one year | Best corrected visual acuity |
| ERG B-wave | one year | — |
| Dark Adaptation | one year | Adaptation time, changes in pupil diameter, threshold to fullfield blue and red light is measured with a fullfield stimulus threshold test (FST) on the ESPION ERG machine (Diagnosys). |
| VFQ-25 | one year | Visual Function Questionnaire (VFQ-25) |
| ERG A-wave | one year | — |
Countries
Germany
Participant flow
Recruitment details
Patients were recruited from the hospital's hereditary retinal degeneration clinic (Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany). Of 88 enrolled participants, 63 met the inclusion criteria and were randomized to treatment.
Participants by arm
| Arm | Count |
|---|---|
| Sham Device was turned on but no stimulation was performed. | 20 |
| 150% Transcorneal electrostimulation with 150% of phosphene threshold. | 15 |
| 200% Transcorneal electrostimulation with 200% of phosphene threshold. | 17 |
| Total | 52 |
Baseline characteristics
| Characteristic | Sham | 150% | 200% | Total |
|---|---|---|---|---|
| Age, Continuous | 48 years STANDARD_DEVIATION 15 | 42 years STANDARD_DEVIATION 13 | 49 years STANDARD_DEVIATION 16 | 46 years STANDARD_DEVIATION 15 |
| Region of Enrollment Germany | 20 participants | 15 participants | 17 participants | 52 participants |
| Sex: Female, Male Female | 11 Participants | 7 Participants | 7 Participants | 25 Participants |
| Sex: Female, Male Male | 9 Participants | 8 Participants | 10 Participants | 27 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 22 | 0 / 21 | 0 / 20 |
| other Total, other adverse events | 13 / 22 | 18 / 21 | 20 / 20 |
| serious Total, serious adverse events | 0 / 22 | 0 / 21 | 0 / 20 |
Outcome results
Primary
Visual Field, III4e
Change in the area measured by kinetic visual field measurement
Time frame: one year
| Arm | Measure | Group | Value (MEAN) |
|---|---|---|---|
| Sham | Visual Field, III4e | Baseline | 4835.29 deg2 |
| Sham | Visual Field, III4e | 1 year | 4488.39 deg2 |
| 150% | Visual Field, III4e | Baseline | 4988.43 deg2 |
| 150% | Visual Field, III4e | 1 year | 4962.76 deg2 |
| 200% | Visual Field, III4e | Baseline | 6234.59 deg2 |
| 200% | Visual Field, III4e | 1 year | 5878.75 deg2 |
Primary
Visual Field, V4e
Change in the area measured by kinetic visual field measurement
Time frame: one year
| Arm | Measure | Group | Value (MEAN) |
|---|---|---|---|
| Sham | Visual Field, V4e | Baseline | 7135.77 deg2 |
| Sham | Visual Field, V4e | 1 year | 6730.20 deg2 |
| 150% | Visual Field, V4e | Baseline | 7599.65 deg2 |
| 150% | Visual Field, V4e | 1 year | 7641.55 deg2 |
| 200% | Visual Field, V4e | Baseline | 8303.59 deg2 |
| 200% | Visual Field, V4e | 1 year | 8112.18 deg2 |
Secondary
BCVA
Best corrected visual acuity
Time frame: one year
Secondary
Dark Adaptation
Adaptation time, changes in pupil diameter, threshold to fullfield blue and red light is measured with a fullfield stimulus threshold test (FST) on the ESPION ERG machine (Diagnosys).
Time frame: one year
Secondary
ERG A-wave
Time frame: one year
Secondary
ERG B-wave
Time frame: one year
Secondary
VFQ-25
Visual Function Questionnaire (VFQ-25)
Time frame: one year