Red eye: conjunctivitis, dry eye or an emergency?

Common causes

• Conjunctivitis of viral, bacterial or allergic origin: red eyes, watering or discharge, itching, without reduced vision.
• Dry eye and blepharitis: stinging, a gritty sensation (see dry eye).
• Subconjunctival haemorrhage : a bright red, painless patch, often harmless.

Signs requiring prompt medical advice

• Marked pain, sensitivity to light, reduced vision.
• Red eye in a contact lens wearer: remove the lenses and seek advice promptly.
• Injury, product splash, foreign body.
• Redness with headaches, nausea and halos around lights.

What to avoid

Avoid eye drops from the “family medicine cabinet” kept after a previous infection, especially corticosteroid drops without medical advice. Avoid rubbing your eyes and wearing contact lenses if you have redness.

Prevention

Wash your hands, do not share towels or make-up, and follow contact lens hygiene (see contact lens care).