Abstract
Purpose :
Transcorneal electrical stimulation (TES) is reported to be effective for the treatment of retinitis pigmentosa, retinal artery occlusion, non-ishchemic optic neuropathy, traumatic optic neuropathy, and Best vitelliform macular dystrophy. We performed a prospective, long-term, case-series study to explore the safety and efficacy of TES for the treatment of primary open-angle glaucoma (POAG).
Methods :
Ten eyes from 6 male subjects with POAG were enrolled in this study. Among 6 POAG patients, 4 patients had normal-tension glaucoma. Average age was 58.7 ± 15.2 years. The subjects in this study underwent TES every 2-3 months for 4 years. The procedure of TES treatment was as follows: First, the DTL electrode was placed on the lower conjunctiva. Then, the electric current pulses were delivered by a stimulator (BPG-1,BAK Electronics, Inc.) and a stimulus isolation unit (BSI-2). Next, the current of the biphasic pulses (10msec; 20Hz) was increased to determine the threshold current necessary to elicit the phosphenes. Then, the current evoking the phosphenes which the patient perceived in the whole visual area was delivered continuously for 30 min using the biphasic pulses. Ophthalmic examinations including visual field testing using Humphery visual field testing (SITA standard 30-2) were assessed according to the study plan. All the patients performed visual field testing at least three times before enrollment in this study. Changes in MD value were evaluated by linear regression model. Among ten eyes, three eyes underwent visual field test only once, therefore, we excluded these three eyes from the analysis.
Results :
During the study period, TES was performed 16.9 ± 8.5 times and for 34.9 ± 17.6 months [range 6 - 48]. Average pre-TES IOP, BCVA, and MD values were 12.3 ± 1.8 mm Hg, 0.44 ± 0.66 (LogMar) and -20.7 ± 7.1 dB. The average MD value was -21.0 ± 8.6 dB (p=0.53 vs pre-TES paired t-test, 6 months), -17.4 ± 6.8 (p=0.58, 12 m), -15.9 ± 5.9 (p=0.07, 18 m), -19.4 ± 6.2 (p=0.64, 24 m), -17.0 ± 6.7 (p=0.48, 30 m), -17.0 ± 7.8 (p=0.74, 36 m) and -12.6 ± 3.9 (p=0.30, 48 m). However, positive trends were discovered (β=0.462, p=0.001) between the number of times TES was performed and the change in MD value. No serious adverse event was observed during the study period.
Conclusions :
TES treatment may improve glaucomatous visual field defect in subjects with POAG.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.