Efficacy and safety of transdermal electrical stimulation in patients with nonarteritic anterior ischemic optic neuropathy

BACKGROUND: No effective treatment for NAION with strong evidence has been established till date. The aim of this investigator-led, prospective, non-randomized, open-label, uncontrolled multi-center exploratory clinical trial is to evaluate the efficacy and safety of transdermal electrical stimulation (TdES) using skin electrodes in patients with NAION. METHODS: Five patients with monocular NAION underwent TdES (10-ms biphasic pulses, 1.0 mA, 20 Hz, 30 min) of the affected eye six times at 2-week intervals. The primary endpoint was the logarithm of the mini-mum angle of resolution (logMAR) visual acuity at 12 weeks compared with 0 weeks. The secondary endpoints were changes in the best-corrected logMAR visual acuity, Early Treatment of Diabetic Retinopathy Study (ETDRS) visual acuity, and mean deviation (MD) of the Humphrey field analyzer (HFA) 10–2 and HFA Esterman test scores. Additionally, the safety of TdES was evaluated. RESULTS: LogMAR visual acuity improved by ≥ 0.1 in two eyes, and ETDRS visual acu-ity improved by ≥ 5 characters in one eye. The mean change in logMAR visual acuity from week 0 showed an increasing trend. The mean MD of HFA 10–2 showed no obvious change, while HFA Esterman score improved in four eyes. All patients completed the study according to the protocol, and no treatment-related adverse events were observed. CONCLUSIONS: TdES treatment may have improved visual acuity and visual field in some patients. Further sham-controlled study in larger cohort is needed on its effectiveness. TRIAL REGISTRATION: UMIN, UMIN000036220. Registered 15 March, 2019, https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000041261. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s42234-023-00125-2.