498
Retinal abnormalities, including retinal hemorrhage and "cotton-wool" spots, often occur within the first 8 weeks in the course of interferon therapy in patients with chronic hepatitis C.
 ( adverse event: occur ,  patients with chronic hepatitis C.: Subject, Retinal abnormalities, including retinal hemorrhage and "cotton-wool" spots: Effect, interferon: Treatment, 8 weeks: Treatment.Time_elapsed, interferon: Treatment.Drug, chronic hepatitis C.: Treatment.Disorder) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: adverse event,potential therapeutic event, Arguments type: Treatment.Disorder,Treatment.Time_elapsed,Treatment.Dosage,Subject.Race,Treatment.Drug,Treatment.Route,Subject.Disorder,Treatment.Freq,Treatment,Effect,Subject.Population,Treatment.Duration,Combination.Drug,Subject,Subject.Age,Subject.Gender. 
Text: {0} 
Answer:
 ( adverse event: occur ,  patients with chronic hepatitis C.: Subject, Retinal abnormalities, including retinal hemorrhage and "cotton-wool" spots: Effect, interferon: Treatment, 8 weeks: Treatment.Time_elapsed, interferon: Treatment.Drug, chronic hepatitis C.: Treatment.Disorder) 