Utility Of Optical Coherence Tomography In The Evaluation Of Patients With Ethambutol-Induced Optic Neuropathy

In this study, optical coherence tomography (OCT) was used to evaluate retinal thickness in two patients with optic neuropathy who had recently discontinued ethambutol. OCT was used to measure retinal nerve fiber layer (RNFL) thickness and to map the RNFL, ganglion cell layer (GCL), and inner plexiform layer (IPL). Decreased RNFL thickness was observed in one case. However, the combined RNFL, GCL, and IPL map showed significant decreases in retinal thickness in both cases, suggesting that ethambutol likely affects the GCL as well as the RNFL. I propose that the GCL thickness should be considered in addition to the RNFL thickness while monitoring ethambutol-induced optic neuropathy.