Effect of Steroid Pulse Therapy on Ethambutol-induced Optic Neuropathy

Abstract

Purpose: This study investigated the effects of high-dose steroid injections for ethambutol-induced optic neuropathy.Methods: A retrospective study examined 13 patients diagnosed with ethambutol-induced optic neuropathy at Wonju Severance Christian Hospital from December 2016 to November 2020. Methylprednisolone was injected at 1,000 mg/day for 3 days. The patients were evaluated before treatment; immediately after it; and at 1, 6, and 12 months. Visual acuity and visual fields were tested (Humphrey Field Analyzer, Carl Zeiss Meditec, Dublin, CA, USA) and the visual field index (VFI) and mean deviation (MD) were recorded.Results: We analyzed 26 eyes of 13 patients (6 males, 7 females; average age 68.7 years). Immediately after treatment, there was no significant improvement in visual acuity, but the VFI improved by 10% or more in 11 eyes and MD improved by 2 dB or more in 16 eyes. After the end of treatment, 13 of 26 eyes showed improved visual acuity of two lines or more in the Snellen table; VFI improved by more than 10% in 16 eyes and MD b y 2 dB or more in 20 eyes. The average differences in the final VFI and MD were 25.96 (standard deviation [SD] = 29.33) and 7.29 (SD = 7.09), respectively.Conclusions: When patients with ethambutol-induced optic neuropathy were treated with high-dose steroid injections, 60% (16/26) showed visual field improvement immediately after treatment and 77% (20/26) ultimately showed improvement. This suggests that steroids have a therapeutic effect in patients with optic neuropathy caused by ethambutol. Further studies are needed.