@entity3110 is one of the routinely used drugs as the first line of antitubercular agents. The delayed onset of @entity2194 is usually thought to be reversible following rapid withdrawal of the drug. We collected ten consecutive @entity1 with severe @entity227 due to @entity3110 @entity137 , and these @entity1 had received presumably safe @entity3110 dosages. Although @entity3110 was stopped immediately in all cases, only five @entity1 (50%) experienced visual improvement after a period of 12 months to 3 years follow-up. The other five @entity1 (50%) had permanent @entity227 without recovery. There were no predisposing or risk factors to contribute to poor visual outcome. In the group over 60 years old, only 20% (1/5) experienced visual improvement; in the group less than 60 years old, 80% (4/5) had some visual recovery, the difference between these two age groups being statistically significant. We need more @entity1 collections to answer whether the older @entity1 with @entity3110 @entity1781 have poor prognoses. @entity3110 @entity1781 , in our follow-up study, is not always reversible, especially in the older population. It may cause permanent @entity227 . There is no so-called "safe-dosage". We suggest reconsideration regarding the use of @entity3110 as one of the first-line antitubercular drugs, especially in older @entity1 .

Reversibility of XXXX @entity1781 .

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity3110 :: ('MESH:D004977', 'Chemical') :: ['Ethambutol hydrochloride', 'ethambutol', 'Ethambutol'] @entity2194 :: ('MESH:D005128', 'Disease') :: ['ocular toxicity'] @entity137 :: ('MESH:D064420', 'Disease') :: ['toxicity'] @entity227 :: ('MESH:D014786', 'Disease') :: ['visual disability', 'visual defects', 'visual impairment'] @entity1781 :: ('MESH:D009901', 'Disease') :: ['optic neuropathy']
@entity3110 :: (MESH:D004977,Chemical) :: ['ethambutol']
