Scanning Laser Polarimetry in Pulmonary Tuberculosis Patients on Chemotherapy

Abstract

Introduction: The aim of this study was to analyse the thickness of the retinal nerve fibre layer (RNFL) of pulmonary tuberculosis patients on ethambutol and isoniazid. Materials and Methods: This was a prospective cohort study where patients with newly diagnosed pulmonary tuberculosis requiring chemotherapy, including ethambutol and isoniazid, were imaged using scanning laser polarimetry. Their mean baseline RNFL thickness and various scanning laser polarimetry parameters of both eyes were measured 2 weeks after the commencement of chemotherapy. The measurements were repeated at 3 months and 6 months after treatment. The various parameters of the baseline and the follow-up measurements were compared using paired sample t-test with Bonferroni correction. Results: Twenty-four patients (16 males and 8 females; mean age, 51.0 ± 17.6 years) were recruited. There was no statistically significant difference between the baseline and the follow-up measurements in RNFL thickness and all other scanning laser polarimetry parameters. Conclusion: In this cohort of subjects, there was no subclinical change in RNFL thickness detected by scanning laser polarimetry in pulmonary tuberculosis patients on chemotherapy, including ethambutol and isoniazid, after 6 months of treatment. Key words: Drug toxicity, Ethambutol, Isoniazid, Lasers, Optic diseases, Retina, Tuberculosis