Review Question - QID 108988

An 82-year-old man with a history of atrial fibrillation presents to the emergency room complaining of sudden-onset, painless vision loss in his right eye starting 2 days ago. When it started, he felt like a “curtain was pulled down” over his right eye but wasn't able to seek care immediately because it was snowing outside and he didn't want to travel in inclement weather. A review of systems is significant for occasional palpitations and presyncope. The patient’s medications include aspirin and carvedilol. He reports that he is a smoker with a 50-pack-year history. The patient’s temperature is 99°F (37.2°C), blood pressure is 112/72 mmHg, pulse is 84/min, and respirations are 14/min with an oxygen saturation of 97% on room air. Physical exam reveals 20/800 vision in the right eye. A fundoscopic exam of the right eye is shown in Figure A. Physical and fundoscopic examinations of the left eye are unremarkable. Which of the following is the most appropriate next step in management?