# A pilot study of the safety and feasibility of transcutaneous electrical nerve stimulation (TENS) for chronic ocular pain

> **NIH VA I21** · MIAMI VA HEALTH CARE SYSTEM · 2022 · —

## Abstract

The aims of the proposed work are to: 1) evaluate the safety and side-effect profile of long-term
Transcutaneous Electrical Nerve Stimulation (TENS) use in neuropathic ocular pain (NOP) patients; 2) assess
the feasibility and acceptability of the Active and Sham TENS protocols for use in a future, randomized-
controlled trial; 3) estimate the time-course of analgesic effect of long-term use of TENS for NOP; and 4)
explore between-subject variability in feasibility, safety, and analgesic responsiveness to TENS for NOP. This
pilot study will enroll 50 Veterans with chronic (>6 mo) NOP (without associated tear film abnormalities) of at
least moderate intensity (≥ 4 on a 0 – 10 pain rating scale).
Participants will be assessed with regard to baseline characteristics, including demographics, medical and pain
history, characteristics and impact of ocular pain, eye exam metrics, and evoked pain sensitivity (Visit 1).
Participants will then be randomized, in a 2:1 ratio, to Active or Sham TENS therapy. An initial in-lab 20-minute
session of TENS will be performed and reports of side effects and ocular pain relief will be recorded at multiple
time points for 120 minutes afterward (Visit 2). After participants are instructed on how to safely apply and start
the TENS device, they will leave the laboratory with the Active or Sham device to initiate the 3-times-per-week
treatment protocol (20 mins per session) at home, for a duration of 6 months. Participants will be assessed
with regard to the frequency and severity of side-effects, frequency of use of the device, and pain ratings via bi-
weekly phone calls with the study staff. At the mid-point (3 months) and end-of-treatment (6 months) time
points, participants will return to the lab for assessments of pain characteristics, eye exam metrics, and evoked
pain sensitivity measures (Visits 3 and 4). The utilization log recorded by the TENS device will also be
downloaded at that time. Additional long-term follow-up data collection will occur via monthly phone interviews,
up to 12 months, to capture the presence of any lingering side-effects and change in ocular pain ratings.
The TENS device to be used is the Cefaly Dual ® (Cefaly Technology, Belgium), which delivers biphasic
rectangular impulses (impulse width 250μS, frequency 60Hz) of up to 16mAmps in intensity via a single
electrode that is placed on the forehead just above the eyebrows. The device has previously been shown to be
effective for the reduction of migraine.
Primary analyses will consist of descriptive statistics to assess: 1) the feasibility for recruitment and retention
into a future efficacy trial (goal is enrollment of at least 50% of eligible patients, and retention of 80% of those
enrolled); 2) the safety of the device (goal is that no more than 10% of participants report mild-moderate side
effects that do not persist; and 0% report a severe side-effect related to the TENS treatment); and 3) the
feasibility of the Sham TENS device (goal is t...

## Key facts

- **NIH application ID:** 10486158
- **Project number:** 1I21RX003883-01A1
- **Recipient organization:** MIAMI VA HEALTH CARE SYSTEM
- **Principal Investigator:** Elizabeth Roy Felix
- **Activity code:** I21 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2022
- **Award amount:** —
- **Award type:** 1
- **Project period:** 2022-07-01 → 2024-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10486158

## Citation

> US National Institutes of Health, RePORTER application 10486158, A pilot study of the safety and feasibility of transcutaneous electrical nerve stimulation (TENS) for chronic ocular pain (1I21RX003883-01A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10486158. Licensed CC0.

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