Quick answer. Most red eyes are due to conjunctivitis (eye infection) or dry eye and settle with simple care. A red eye with severe pain, vision loss, halos around lights, or after an injury can mean acute glaucoma or another serious problem – seek urgent eye care.
A red eye means the white of the eye looks pink or red, usually because small blood vessels on the surface are inflamed or dilated. It is one of the most common eye complaints.
This guide explains the common and serious causes of a red eye, the emergency warning signs, and which specialist to see in Singapore.
At a glance
| Cause | What it may suggest | Urgency |
|---|---|---|
| Red, watery or sticky eye, often both eyes, with discharge | Conjunctivitis (viral or bacterial eye infection) | Routine – often self-limiting; see a doctor if severe |
| Gritty, burning, tired eyes that worsen on screens or in aircon | Dry eye | Routine – eye drops and lifestyle measures usually help |
| Small bright-red patch on the white of one eye, no pain | Subconjunctival haemorrhage (burst surface vessel) | Routine – usually harmless and clears on its own |
| Red eye with itching, swelling and watering, with allergies | Allergic conjunctivitis | Routine – antihistamine or allergy eye drops help |
| Red eye with severe pain, blurred vision, halos around lights | Possible acute glaucoma or other serious cause | Emergency – seek urgent eye care immediately |
Emergency: red eye warning signs that need urgent care
Most red eyes are minor, but some signal a sight-threatening problem. Seek urgent eye care immediately if a red eye comes with any of the following:
- Severe eye pain
- Sudden or worsening loss of vision, or blurred vision
- Halos or rainbow rings around lights
- Nausea or vomiting with eye pain and headache
- A red eye after an injury, or after a chemical or foreign body entering the eye
- Sensitivity to light, or a red eye in a contact lens wearer with pain
A painful red eye with vision loss and halos can be acute angle-closure glaucoma, where eye pressure rises sharply and vision can be lost without prompt treatment. Go to an eye emergency service or A&E without delay. In a medical emergency in Singapore, call 995.
What causes a red eye?
The white of the eye is covered by a thin membrane called the conjunctiva, which carries fine blood vessels. When these vessels become inflamed, irritated or dilated, the eye looks red. The cause can be on the surface (such as infection or dryness) or, less commonly, inside the eye (such as raised pressure or inflammation), which tends to be more serious.
Common vs serious causes
Common, usually mild causes: conjunctivitis (viral, bacterial or allergic), dry eye, eye strain, a burst surface blood vessel (subconjunctival haemorrhage), and minor irritation from smoke, dust or contact lenses.
Serious causes are less common but important: acute angle-closure glaucoma, inflammation inside the eye (uveitis or iritis), a corneal ulcer or infection (a particular risk for contact lens wearers), scleritis, and eye injury. These usually cause significant pain or affect vision, which is why those features are red flags.
Self-care and treatment
For mild conjunctivitis, clean the eyelids gently with cooled boiled water, avoid rubbing, use a separate towel and wash your hands often, as viral conjunctivitis spreads easily. Most viral cases settle in 1-3 weeks. For dry eye, lubricating eye drops, regular screen breaks, and reducing aircon and fan exposure can help.
Stop wearing contact lenses while your eye is red, and do not use old or other people’s eye drops. If symptoms are severe, not improving, or any red-flag feature appears, seek eye care rather than continuing self-care.
Which specialist should you see?
Mild conjunctivitis or dry eye can often be managed by a GP or optometrist. For a painful red eye, reduced vision, halos, an eye injury, a red eye in a contact lens wearer, or symptoms that do not improve, you should be assessed by an eye specialist (ophthalmologist) – urgently if the symptoms are severe. You can find one among our listed eye specialists.
If you suspect acute glaucoma or any sight-threatening problem, do not wait for a routine appointment – go to an eye emergency service or A&E.
How to prepare for your appointment
If you are seeing a GP, optometrist or eye specialist, note when the redness started, whether one or both eyes are affected, and any discharge, itching, grittiness or pain. Crucially, record any change in vision, halos around lights, or recent eye injury, as these guide how urgently you are seen. Tell the clinic if you wear contact lenses, as a painful red eye in a lens wearer needs prompt assessment for a corneal infection. Bring your spectacles or lens details and a list of any eye drops you have used. Avoid wearing contact lenses to the appointment if your eye is red and uncomfortable.
What to expect at the appointment
The clinician will ask about your symptoms and check your vision. They may examine the eye with a bright light or a slit lamp, sometimes after putting in a drop that stains the surface to reveal scratches or ulcers. If raised eye pressure is a concern, they will measure it. Most cases of conjunctivitis, dry eye or a burst surface vessel are diagnosed from the examination alone and need no scans. If a serious cause such as acute glaucoma, uveitis or a corneal ulcer is suspected, you will be referred for same-day specialist care.
Self-management at home
For mild infective conjunctivitis, wash your hands often, use a separate towel and pillowcase, and avoid sharing eye make-up to limit spread, as viral conjunctivitis is highly contagious. Clean any discharge gently with cooled boiled water on a fresh swab. For dry, gritty eyes, lubricating drops, regular screen breaks and reducing direct air-conditioning or fan flow help. Do not rub the eye, and stop wearing contact lenses until the eye is fully settled and a clinician confirms it is safe. Never use someone else’s prescription eye drops, and seek care promptly if pain or blurred vision develops.
Costs and subsidies in Singapore
A GP or optometrist can manage many minor red eyes, and eligible Singapore Citizens may receive CHAS subsidies at participating GP clinics; polyclinics also offer subsidised consultations. Ophthalmologist review at a public hospital attracts subsidised rates for referred subsidised patients, while private clinics charge market rates. For an emergency such as suspected acute glaucoma, go to an eye emergency service or A&E without worrying about cost first; sight is time-sensitive.
Common questions
How do I know if my red eye is an emergency?
Severe pain, loss or blurring of vision, halos around lights, nausea with eye pain, an injury, or a painful red eye in a contact lens wearer all need urgent eye care. A comfortable red eye with normal vision is usually minor.
Will conjunctivitis clear on its own?
Most viral conjunctivitis settles within one to three weeks with hygiene measures. See a doctor if it is very severe, not improving, or you are unsure of the cause.
Can I wear contact lenses with a red eye?
No. Stop wearing lenses while the eye is red and only resume once a clinician confirms the eye has fully recovered.
Related guides
- Best Eye Clinics in Singapore — our editorial shortlist
- eye clinics directory
- Mouth ulcers
- Jaw pain & TMJ
- Lump in the throat (globus)
Sources
- SingHealth – Conjunctivitis and Viral Conjunctivitis
- SingHealth – Glaucoma: Symptoms & Treatment
- SingHealth – Dry Eye Syndrome
- NHS – Red eye
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