<prompt> Eye defect by anti Tb drug:EthambutolPyrazinamideRifampicinIsoniazid  <response>: Ans. a. EthambutolRef: Goodman Gilman 13th EP1074Reversible eye defect in the form of optic neuritis and red-green greenred colour blindness can be seen with ethambutol.Hence ophthalmological examination for same is mandatory.These intensity of ocular toxicities are both dose and duration dependent. 