Diagnosis	Characteristics
Acute angle-closure glaucoma	Diffuse conjunctival redness, especially adjacent to the limbus; ocular pain may be accompanied by headache and blurry or decreased vision; abdominal pain, nausea, and vomiting may be present; usually unilateral, pupil mid-dilated and nonreactive
Episcleritis	Localized or diffuse redness, dull ache, tender on palpation; normal vision; responds to corticosteroids or oral nonsteroidal anti-inflammatory drugs
Hyphema	Layering of blood in the anterior chamber; possible decreased visual acuity, photophobia, eye pain
Subconjunctival hemorrhage	Sharply demarcated area of bright redness; painless; normal vision; resolves spontaneously
Viral conjunctivitis	Diffuse redness, watery discharge; often associated with a viral upper respiratory tract infection