Optic neuropathy by ethambutol in a patient with multiple sclerosis.

We present the clinical case of a patient who developed a toxic optic neuropathy due to ethambutol in the context of a tuberculosis reactivation and who also had a personal history of multiple sclerosis. The objective is to highlight the importance of making a good differential diagnosis of this adverse effect and of knowing its main clinical, campimetric and tomographic manifestations and characteristics. Furthermore, since the reversibility of damage is still discussed in the literature, early diagnosis is essential. For this purpose, it is important to inform the patient of the possible symptoms and to carry out an ophthalmological examination and colour tests before starting treatment to assess whether there is progression.