To Study Optic Neuropathy in Multi Drug Resistant Tuberculosis Patients on Linezolid Based Regimen

Abstract

Background: Multidrug-resistant tuberculosis (MDR-TB) remains a major global health challenge, necessitating prolonged treatment with second-line anti-tubercular drugs such as linezolid. Although linezolid has demonstrated significant efficacy against MDR-TB, its long-term use is associated with adverse effects, particularly optic neuropathy, which can lead to irreversible visual impairment if not detected early. Aim and Objectives: To study the magnitude of linezolid-induced optic neuropathy in MDR-TB patients and to assess the clinical ophthalmological profile of these patients. Materials and Methods: A cross-sectional observational study was conducted over a period of 18 months at a tertiary care center. Forty MDR-TB patients receiving linezolid-based regimens for more than three months were included. Comprehensive ophthalmological evaluation was performed, including assessment of visual acuity, colour vision, contrast sensitivity, pupillary reactions, fundus examination, and visual field screening. Data were analyzed using SPSS version 24.0, and associations were evaluated using the chi-square test, with p < 0.05 considered statistically significant. Results: Among the 40 patients studied, a high proportion demonstrated features suggestive of linezolid-induced optic neuropathy. Decreased visual acuity (<6/60) was observed in more than 50% of patients. Fundus abnormalities were noted in 28 patients, including hyperemic disc (13 cases), disc pallor (11 cases), and disc edema (4 cases). A statistically significant association was found between duration of linezolid therapy and fundus changes (p = 0.0001). Reduced contrast sensitivity was observed in 16 patients and showed a significant association with duration of therapy (p = 0.004). Colour vision defects were identified in 9 patients and were more common with prolonged linezolid use. Relative afferent pupillary defect was present in 8 patients, though this association was not statistically significant. Conclusion: Linezolid-induced optic neuropathy is a significant and duration-dependent adverse effect in patients undergoing long-term treatment for MDR-TB. Regular ophthalmological screening, including visual acuity, colour vision, contrast sensitivity, and fundus examination, is essential for early detection and prevention of irreversible visual loss.

Keywords: Multi Drug Resistant Tuberculosis; Linezolid; Optic Neuropathy; Visual Impairment; Colour Vision Defect