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  • Visual Recovery After Ethambutol-Induced Optic Neuropathy

    By Jean Shaw
    Selected by Prem S. Subramanian, MD, PhD
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    Journal Highlights

    Clinical Ophthalmology
    2023;17:545-554

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    Ethambutol-induced optic neuropathy (EON) is an uncommon but well-rec­ognized adverse event in patients who take the antituberculosis drug etham­butol. Although some researchers have found that patients recover vision after immediate discontinuation of etham­butol, others have reported irreparable damage. Srithawatpong et al. set out to study visual recovery and identify the factors that may contribute to it in patients with EON. They found that EON damage was not always revers­ible—and that initial VA was the only factor that appeared to correlate with visual recovery.

    For this retrospective observational study, the researchers evaluated the charts of patients who were diagnosed with tuberculosis and treated with ethambutol between 2012 and 2021 in a tertiary eye center. The primary outcome was visual recovery, which was defined as experiencing improve­ment from the initial VA assessment and achieving a final BCVA of 20/50 or better once the drug was discontinued.

    Of 5,394 patients diagnosed with tuberculosis during the 10-year study period, 23 (.43%) were diagnosed with EON. All 23 developed impaired vision in both eyes. After ethambutol was discontinued, good visual recovery was achieved in nine (39.13%) of the 23 patients, while poor visual recovery was noted in the remaining 14 (60.87%). The mean daily dose of ethambutol was slightly higher in those who achieved good visual recovery, but this did not reach statistical significance (p = .55). Similarly, no statistically significant differences were noted between the two groups of patients with regard to age, body weight, mean duration of etham­butol treatment, or cumulative dose of ethambutol.

    After adjustment with multivariate analysis, initial VA was found to be the only significant factor associated with visual recovery: specifically, only those eyes with initial BCVA of 20/200 or better at presentation recovered vision.

    In their discussion, the authors recommend that ophthalmologists regularly screen patients who are taking ethambutol. Ophthalmologists and pulmonologists should work together to minimize the risk of EON—and if it is discovered, ethambutol should be immediately discontinued.

    The original article can be found here.