Red eye — decoding the cause and urgency
A red eye is one of the least specific eye complaints — it can be anything from mild allergic irritation to a genuine sight-threatening emergency. Two things separate the safe from the serious: pain and blurred vision.
What can cause this — and how each feels different.
Viral or allergic conjunctivitis
Watery discharge, itching, both eyes usually involved. Vision is normal, no significant pain.
Bacterial conjunctivitis
Sticky yellow-green discharge, eyelids stuck in the morning. Antibiotic drops speed recovery.
Dry eye disease
Burning, foreign-body sensation, worse with screens. Redness is mild but recurrent.
Subconjunctival haemorrhage
A dramatic bright-red patch that looks alarming but is painless and harmless — usually clears in 10-14 days.
Corneal ulcer or keratitis
Red eye with severe pain, light sensitivity, and blurred vision — a red flag, particularly in contact lens wearers.
Acute angle-closure glaucoma
Red eye with severe pain, nausea and blurred vision with halos around lights — a genuine emergency.
When to seek care — a practical guide.
Use the guide below only as a starting point. If you are unsure, run the free AI Symptom Checker or simply message us on WhatsApp — we would rather see you and reassure you than miss something serious.
Questions patients ask us most.
Can I use over-the-counter drops for a red eye?
Lubricant / artificial tear drops are safe. Do not use steroid drops without an examination — they can turn a corneal ulcer into a severe vision-threatening infection.
How long does viral conjunctivitis last?
5-10 days on average. It is contagious for the first week — wash hands often and use separate towels.
Is a red eye in a contact lens wearer serious?
Always take it seriously. Stop the lens immediately, keep the lens case, and come in the same day — contact-lens corneal ulcers are one of the fastest-progressing eye emergencies.
The AI Eye Symptom Checker is an educational triage aid only. It cannot examine your eye and it cannot make a diagnosis. It is not a substitute for a physical, in-person consultation with an ophthalmologist. If you have any doubt, please book an appointment or come to the clinic.Concept by Dr. Shantanu Kumar Gupta & Dr. Manisha Mishra · Developed with AI
This article is for patient education. It is not a substitute for personalised medical advice, examination or diagnosis. If you have symptoms discussed here, please book an in-person consultation with a qualified ophthalmologist.