Purpose: To evaluate the effect of anti-tubercular treatment on retinal nerve fiber layer (RNFL) thickness and the efficiency of optic coherence tomography (OCT) on early diagnosis of optic neuropathy.
Methods: Twenty patients diagnosed with either pulmonary or extra-pulmonary tuberculosis which were treated with anti-tubercular treatment (isoniazid (INH), rifampicin, ethambutol (ETM), and pyrazinamide) were enrolled in the study. RNFL thicknesses of the patients were measured via OCT, at baseline (before starting anti-tubercular treatment) and after the two-month treatment period. Standard ophthalmologic examinations were also performed.
Results: Compared to baseline values, after the two-month treatment period, thinning was detected in the right eye's average and superior quadrant RNFLs (p = 0.024 and p = 0.006 respectively) and in the left eye's average, superior quadrant, and inferior quadrant RNFLs (p = 0.001, p = 0.008, p < 0.001, respectively).
Conclusion: We displayed that patients receiving INH and ETM, which were the basic medicines of anti-tubercular treatment, experienced thinning in RNFL after the two-month treatment period. Patients receiving these drugs can be followed via OCT in terms of reduction in RNFL thicknesses for early diagnose of INH and ETM toxicity.
Keywords: Ethambutol; isoniazid; optic coherence tomography; retinal nerve fiber layer thickness.