A 45-year-old man presents to an urgent care facility with a two-day history of worsening unilateral eye pain, significant photophobia, and blurred vision in his right eye. He reports a preceding viral prodrome with mild flu-like symptoms a week prior. He has been self-treating with over-the-counter decongestant eye drops and, more recently, a friend's leftover topical corticosteroid eye drops for what he thought was severe allergic conjunctivitis. On examination, his visual acuity is significantly reduced in the affected eye, and there is circumcorneal injection. Pupillary light reflex is sluggish in the right eye. Slit-lamp examination, after fluorescein staining, reveals a characteristic superficial branching lesion with terminal bulbs. Gram’s stain and Giemsa stain of corneal scrapings are negative for bacterial or fungal elements. What is the most probable diagnosis and the most appropriate initial management strategy?