Review Question - QID 213675

A 23-year-old man presents to the emergency department with red eyes. The patient states that 2 days ago his left eye was red, and he noticed more tearing. He states the eye was itchy and had a minor cough and some ear pain at the time. Since then, his cough and ear pain has resolved but the redness in his eye has not improved and has spread to the contralateral eye. The patient states he may have been hit in the eye with a strap from his backpack prior to the onset of his symptoms. He is otherwise healthy and has no other symptoms including pain or changes in his vision. His temperature is 97.9°F (36.6°C), blood pressure is 122/74 mmHg, pulse is 81/min, respirations are 14/min, and oxygen saturation is 98% on room air. Physical exam is notable for bilateral red eyes with a thin, watery discharge. The patient’s vision test is within normal limits. Which of the following is the most likely diagnosis?