Is Ethambutol more associated with a red/green or blue/yellow color defect?

Ethambutol is an antibiotic commonly used to treat tuberculosis, and it has known ocular side effects, particularly affecting color vision. The primary color vision defect associated with Ethambutol is a red/green color deficiency. This occurs due to the drug's effect on the retinal ganglion cells, specifically the ones responsible for processing red and green colors.

When patients experience a red/green color defect, they may find it difficult to distinguish between these colors, resulting in confusion and visual disturbances. The mechanism behind this is related to the drug's toxicity to the optic nerve, leading to optic neuritis or other forms of optic neuropathy, where the red and green photoreceptors are primarily impacted.

While Ethambutol can affect color vision, it does not typically cause blue/yellow defects. Thus, the association with red/green color vision impairment is a well-established characteristic of Ethambutol toxicity.