Farnsworth 100-hue test in diagnosis of ethambutol-induced damage to optic nerve.

In patients treated with EMB, disturbances in colour vision may be the first and only symptoms of the onset of toxic damage to the optic nerves. Owing to its sensitivity, the Farnsworth 100-Hue test is of great value in the ophthalmic control examinations. Moreover, it permits observation of the dynamics of the toxic process. The three reported cases of damage to the optic nerves confirm the great importance of colour vision examinations, as regards the detection of the complications of EMB treatment.