A Hospital Based Prospective Study to Assess the Ocular Manifestations of Anti-Tubercular Drugs in Patients Receiving Anti- Tuberculosis Treatment

Abstract

Background: TB is still the most common infectious disease and a major public health problem, infecting millions of people worldwide. Among ATT, ethambutol is the most commonly implicated drug causing optic neuropathy. The aim of this study to assess the ocular manifestation of anti-tubercular drugs in patients receiving anti-tuberculosis treatment. Material &Methods: This study is an observational follow up study done on 80 patients of newly diagnosed drug susceptible pulmonary tuberculosis, referred to ophthalmology OPD in a Government Medical college, Sikar, Rajasthan were examined. All patients of newly diagnosed pulmonary TB on standard HRZE regimen were examined thoroughly before initiating ATT and thereafter every month up to 6 months during a period of one year. Socio demographic data with patient’s personal identification information was recorded. All the patients were evaluated for best corrected visual acuity by illuminated Snellen chart for 20 feet distance. Colour vision was assessed using Ishihara chart. Visual field testing was done using the Carl Zeiss Meditec HFA 2 Humphrey field analyzer with 30-2 threshold programme, with dim ambient light source with full refractive correction. Results: Mean age of the patients is 32.56 year with maximum number of patients being in age group 18-30 years (56.25%). There were 45 (56.25%) males and 35 (43.75%) females. Colour vision was assessed using Ishihara colour vision plates. During study, it was observed that out of 160 eyes, 10 eyes of five patients (6.25%) showed colour vision abnormality at the end of 6 month follow up. All the patients were followed up at monthly interval up to 6 months and their visual acuity was tested, during which we found that decline in visual acuity from baseline was seen in 12 eyes of six patients (7.5%) in which 2 eyes of one patient had drop in visual acuity at 4th month follow up, 8 eyes of four patients had drop in visual acuity at 5th month follow up and 8 eyes of four patient at 6th month follow up. The most common defect seen was cecocentral scotoma in four (2.5%) eyes out of 160 eyes. Other defects seen were peripheral constriction (2.5%) and peripheral defect in different quadrant (1.25%). Conclusion: We found that ocular toxicity was seen in a significant number of patients (6.25%). The ocular toxicity of ethambutol in our patients had manifested in the form of changes in visual acuity, colour vision, visual field and fundoscopy picture.