687
Two patients who developed decreased visual acuity after several months of ethambutol treatment for Mycobacterium avium-intracellulare infection had bitemporal visual field defects that suggested optic chiasm damage.
 adverse event: after 
Please tell me event type and its trigger word from given type options. Output format is "type: trigger".  Option: adverse event, potential therapeutic event 
Text: {0} 
Answer:
 adverse event: after 