The patient was a 43-year-old woman with a sudden decrease in vision in the left eye two weeks previously. There had been no subsequent change in vision. The past medical history is remarkable for bronchitis with an acute exacerbation about two weeks ago. The visual acuity was 20/20 OD and 20/50 OS. The examination of the right eye was unremarkable. The left fundus and OCT are shown below. What is the most likely diagnosis? What treatment, if any, would you recommend?