Article Text
Abstract
Objective To explore the impact of weekly transcorneal electrical stimulation (TES) over a 6-month period as a treatment for retinitis pigmentosa (RP).
Methods and analysis A prospective open-label observational trial was carried out assessing weekly TES in participants with RP for a period of 6 months followed by observation for a further 6 months. Clinical examination and investigations were carried out at 3 monthly intervals for a total of 12 months. The primary outcome measure explored safety through a descriptive analysis of adverse effects with secondary outcome measures evaluating structural and functional efficacy.
Results Seven male and seven female participants with RP aged 18–80 years were recruited. TES was well tolerated with no serious adverse events reported. Two participants reported transient foreign body sensation and one participant had discomfort underneath the skin electrode. Following 6 months of TES, best-corrected visual acuity increased by 1.1±1.4 letters in the control arm and 0.93±1.4 letters in the treated arm. Central microperimetry threshold sensitivity rose by 0.02±0.5 decibels (dB) and 0.37±0.4 dB and Goldmann visual field volume by 0.16±0.09 steradians (sr) vs 0.22±0.12 sr for the control and treated eye, respectively. There was no statistical significance seen between eyes following the treatment or observation period.
Conclusion This small open-label clinical trial showed that TES was safe and well tolerated in patients with RP. Visual function measurements at 6 months demonstrated no significant difference between the control and treated eyes. The results justify a larger clinical trial over a longer period of time in order to identify any treatment effect.
- treatment other
- retina
- genetics
- degeneration
- clinical trial
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Footnotes
Contributors The project was conceived by FG with design amendments by ARW, SKD and REM. SKW, JKJ, MP, ARW, SMD and REM contributed to acquisition, analysis and interpretation of the data. SKW and JKJ composed the manuscript, which was revised with significant input by MP, FG, ARW, SKD and REM. All authors have approved the final version.
Funding The research was funded by the Oxford Biomedical Research Centre based at Oxford University Hospitals NHS Trust and the University of Oxford and Okuvision GmbH with research infrastructure support from the National Institute for Health Research (NIHR) as a Clinical Research Network Portfolio-adopted study. Okuvision GmbH participated in the design and data monitoring of the trial.
Competing interests All authors except FG were employed by the National Health Service at the time of this work taking place. SD: has previously received support to attend educational meetings from Novartis, a Novartis grant to develop the AMD service and the employer has received funds from Novartis to allow SD to speak at educational events. REM: Director of NightstaRx, a choroideremia gene therapy company established by the University of Oxford and funded by the Wellcome Trust. The company had no role in the conduct, funding or writing up of this study.
Ethics approval The study was approved by the National Health Service (NHS) Research Ethics Committee (REC) and received institutional approval from the Oxford University Hospitals NHS Trust Research and Development Department (12/SW/0293).
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement All data relating to this clinical trial are published. Any requests for data should be addressed to the corresponding author.