<prompt> In ethambutol toxicity there will be loss of ability to see which of the following colour?RedGreenBlueYellow  <response>: Optic neuritis, the most serious adverse effect repoed, typically presents as reduced visual acuity, central scotoma, and loss of the ability to see green or, less commonly, red. Ref: Harrisons Principles of Internal Medicine, 18th Edition, Page 1376. 