The Effect of Anti-Tubercular Drugs on Retinal Nerve Fiber Layer Thickness Using Optical Coherence Tomography

Purpose: To study the effect of anti-tubercular drugs on retinal nerve fiber layer (RNFL) thickness using optical coherence tomography.
 Methods: The study was done in thirty patients newly diagnosed with pulmonary tuberculosis which were given anti-tubercular treatment (isoniazid, rifampicin, ethambutol and pyrazinamide ) at DOTS centre of K. N. TB and Chest hospital (Dr. S.N M C.) Jodhpur. Visual function tests (visual acuity, contrast sensitivity, color vision) and OCT assessment of RNFL done before initiation of treatment and after two month of treatment.
 Results: After two months, RNFL thinning was present in 3 eyes out of total 60 eyes in temporal and superior quadrant.
 Conclusion: The study revealed that the first line antitubercular drug Ethambutol causes RNFL thinning within two months of initiation of drug in the recomonded dose. In the initial stage of optic nerve toxicity, there are no clinically significant changes seen on posterior segment ophthalmoscopic examination and fundus photography.OCT can find out the retinal nerve fiber layer thinning even if there are minute changes.