Field changes on automated Humphrey’s field analyzer in tuberculosis following ethambutol therapy

Abstract

This study was conducted to evaluate the visual field changes in tubercular patients on anti-tubercular therapy and to assess the reversibility of these changes after the discontinuation therapy. This study was conducted as a prospective analytical study at tertiary care centres in Bhopal and Jabalpur on all newly detected tuberculosis patients. Ocular history, relevant history was recorded and detailed ocular examination was done at the time of presentation, before initiating ATT. All the patients were followed up periodically till the cessation of treatment and three months thereafter. A total of 40 cases of newly diagnosed tuberculosis were registered with mean age of 38.4±13.99 years. We documented significant deterioration in visual acuity after 3 months of initiation of therapy. Once the ATT was stopped, the improvement in visual acuity was statistically significant 3 months after the cessation of ATT as compared to visual acuity 3 months after initiation of ATT (p<0.05). But residual visual impairment even after stoppage of ATT was observed. Color vison and visual field defects were observed in higher proportions of eyes following initiation of ethambutol which improved significantly after 3 months of cessation of ATT (p<0.05). Ethambutol, even in recommended dose according to DOTS, has been associated with ocular toxicity which manifests in the form of painless progressive loss of vision, color vision defects and visual field defects. Though these changes are usually reversible, few patients have irreversible damage. Thus, patients receiving ethambutol must be explained regarding these effects and followed up periodically.