An exploratory study to evaluate efficacy and safety of frequent Transcutaneous Electrical Stimulation for Leber...

Electrical stimulation (ES) may be effective for intractable retinal or optic nerve diseases. We studied frequent transcutaneous ES in a single-center, single-arm prospective study in patients with Leber hereditary optic neuropathy (LHON) who carry the mitochondrial (mt) 11778 G > A mutation. A 30-min ES was applied to either eye every other day for 12 weeks. The primary outcome was the difference in the logarithm of the minimum angle of resolution (LogMAR) at baseline and 1 week after completion of ES treatment. The secondary outcomes included changes in visual field; LogMAR; critical flicker frequency; and inner retinal thickness. Safety endpoints included the corneal endothelial cell density and complications during ES. Fourteen patients participated in the study; four dropped out. The median (interquartile range) LogMAR values before stimulation and 1, 4, and 8 weeks after ES were 1.60 (1.45-1.80), 1.70 (1.35-1.80), 1.60 (1.43-1.73), and 1.50 (1.43-1.73), respectively, indicating no significant improvement (primary outcome: Wilcoxon's signed rank test, p = 1.000, secondary outcome: Friedman test, p = 0.229). There were no improvements in any secondary efficacy endpoints and no complications. In conclusion, frequent transcutaneous ES did not improve visual acuity in patients with LHON carrying the mt11778 G > A mutation.