Transcorneal Electrical Stimulation for Patients With Retinitis Pigmentosa: A Prospective, Randomized, Sham-Controlled Follow-up Study Over 1 Year

Invest Ophthalmol Vis Sci. 2017 Jan 1;58(1):257-269. doi: 10.1167/iovs.16-19906.


Purpose: After promising results of an exploratory study, this study was designed to assess the safety and efficacy of transcorneal electrical stimulation (TES) over 1 year in patients with retinitis pigmentosa (RP).

Methods: We included 52 RP patients in this prospective, randomized, partially-masked study which was done in accordance with rules of good clinical practice. Transcorneal electrical stimulation by Okustim was applied monocularly for 30 minutes per week for 52 consecutive weeks. Patients were assigned randomly to the groups: sham, 150%, or 200% of individual electrical phosphene threshold (EPT). Visual acuity (retroilluminated Snellen charts), visual field (VF; Octopus 900), electroretinography (ERG), rod and cone full-field stimulus threshold, EPTs and IOP were assessed. Primary outcome measures were VF area; secondary outcome measures were development of ERG parameters.

Results: The application of TES was tolerated well. Dry eye symptoms (31 of 52 patients) were registered as the main adverse event. Throughout the study period, the VF area showed only a trend for prevention of VF loss in the 200% group (P = 0.24). A significant improvement of light-adapted single flash b-wave was noted for the 200% (P < 0.0001) and 150% (P = 0.006) groups compared to the sham group. Tendencies of improved function were observed for scotopic b-wave amplitude for the 200% group (P = 0.097). Other examination methods did not reach statistical significance.

Conclusions: The safety and acceptable tolerability of weekly TES self-administered by patients at home was confirmed over the course of 1 year. Objectively measured improvements in retinal function with ERG provide support for the potential benefits of TES for RP patients.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Cornea
  • Electric Stimulation / methods*
  • Electroretinography
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Pilot Projects
  • Prospective Studies
  • Retina / physiopathology*
  • Retinal Cone Photoreceptor Cells / physiology
  • Retinal Rod Photoreceptor Cells / physiology*
  • Retinitis Pigmentosa / physiopathology
  • Retinitis Pigmentosa / therapy*
  • Single-Blind Method
  • Treatment Outcome
  • Visual Acuity*
  • Visual Fields*
  • Young Adult