Dry Eye Signs and Symptoms Eased After Transcutaneous Electrical Stimulation

Transcutaneous electrical stimulation (TES) may improve dry eye signs and symptoms following photorefractive keratectomy (PRK), according to a study published in Ophthalmology Science.

Researchers included 24 patients in a prospective, single-center, single-blinded, placebo-controlled, randomized clinical trial and assigned them to treatment with TES (n=12; 6 women; mean age, 28.3 years) or sham treatment (n=12; 7 women, mean age 26.6 years). 

Participants in both treatment arms used an electrode patch to stimulate the ocular surface. Treatment was applied once a day for 15 to 30 minutes for 2 weeks followed by treatment once a week for 2 weeks until 3 months postoperatively. A 2-Hz biphasic pulse was used with a phase and interphase interval of 250-μsec and 5-μsec, respectively, for participants undergoing TES treatment. The sham device had only a 0.5 mA biphasic pulse which was delivered once every 30 seconds.

Dry eye signs and symptoms were evaluated at baseline and during 1-,4-, and 12-week follow-up visits. Patients reported symptoms using the ocular surface disease index (OSDI), 5-item dry eye questionnaire (DEQ-5) and standard patient evaluation for eye dryness 2 (SPEED 2) questionnaires. The researchers performed tear breakup time (TBUT), Schirmer I testing, total corneal fluorescein staining (tCFS) and conjunctival staining on all participants.

No significant differences in OSDI, DEQ-5, and SPEED II  scores were noted between cohorts at the 12-week follow-up visit. The TBUT scores, however, were significantly higher among participants in the TES group (9.28 s) compared with control individuals (5.98 s). This demonstrated a 63% increase in TBUT score from baseline among participants treated with TES (baseline, 5.66 s).

Both tCFS and total conjunctival staining score were significantly lower in the TES group compared with the control group at 4 weeks following PRK. Participants treated with TES reported significantly less pain intensity at week 1 compared with the control group participants (P =.011). No single serious adverse events were reported with device use.

Investigators highlight the unique nature of dry eye disease following surgical procedures. “DED after PRK is different from general dry eye disease and is known to be associated with damage to the corneal afferent nerve during PRK leading to a disruption in sensory input to the ocular surface lacrimal gland feedback system,” the study authors note. “Considering the mechanism of TES, DED related to corneal nerve damage seems to be the best candidate for testing the effects of electrical stimulation.”

Study limitations include a small sample size, single center design and short study duration.