A 61-year-old man is evaluated in an urgent care center for acute frontal headache and pain in the right eye that began a few hours earlier while he was watching his grandson's basketball game. The pain extends through the anterior scalp and downward across the nose. The patient is also nauseated and vomiting acutely. He has photophobia and notes that lights appear "fuzzy." Medical history is significant for hypertension and anxiety. Medications are hydrochlorothiazide and citalopram. On physical examination, blood pressure is 150/90 mm Hg; other vital signs are normal. Severe conjunctival erythema; photophobia; a mid-dilated, nonreactive pupil on the right side; and corneal cloudiness are noted. Upon gentle palpation of the eyes, tenderness and increased firmness are noted over the right globe compared with the left. Right eye visual acuity is grossly decreased. No discharge is noted. Which of the following is the most likely diagnosis?
A. Acute angle-closure glaucoma
B. Bacterial endophthalmitis
C. Central retinal vein occlusion
D. Scleritis