Red eye
A red eye is the sort of complaint nobody hurries about. And usually there is no need to: redness from a sleepless night, from wind, from hours at a screen…
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Medicines commonly prescribed for Red eye
For informational purposes only. Always consult a doctor before taking any medication.
Dosage form: EYEDROP, 1 mg/mlActive substance: dexamethasoneManufacturer: Brill Pharma S.L.Prescription requiredDosage form: EYE DROP, 1 mg/mlActive substance: dexamethasoneManufacturer: Ntc S.R.L.Prescription requiredDosage form: EYEDROP, 1 mg/mlActive substance: dexamethasoneManufacturer: Ntc S.R.L.Prescription required
A red eye is the sort of complaint nobody hurries about. And usually there is no need to: redness from a sleepless night, from wind, from hours at a screen or from a small vessel that has burst clears up on its own. But the same sign also hides a handful of conditions in which an eye loses sight within days, and sometimes within hours. Telling them apart is not difficult, and the whole distinction rests on three things: whether the eye hurts, whether the vision has changed, and how the eye reacts to light.
The red eye that can cost you your sight
See a doctor the same day — and if the onset is dramatic, call an ambulance on the single European number 112 or your local number — if the redness comes with any of these:
- pain inside the eye itself, not just stinging or a gritty feeling: a deep, dull ache spreading to the brow and temple;
- light hurts — looking at a lamp or a window is painful and the eye screws itself shut;
- the vision has got worse: blurring, fog, a patch, haloes or rainbow rings around lights;
- the redness forms a ring around the iris rather than spreading across the white of the eye;
- the pupil has changed shape, looks irregular, differs in size from the other one, or no longer narrows in bright light;
- a severe headache with feeling sick and vomiting alongside a red, painful eye;
- a whitish spot or patch visible on the cornea, the clear dome over the iris;
- heavy pus discharge, or lids so swollen that the eye will not open;
- the eye turned red after an injury, a chemical splash, or recent eye surgery.
Behind that list sit uveitis, an acute attack of glaucoma, keratitis and corneal ulcer, and severe infectious conjunctivitis that has reached the cornea. All of them can be treated if treatment starts in time, and all of them leave lasting loss of vision if you wait.
A separate rule for contact lens wearers
A red eye with pain or reduced vision in someone wearing contact lenses is not the same thing as a red eye without them. A lens creates the conditions for microbial keratitis, and that can destroy the cornea in a day or two. So the rule is simple and has no exceptions:
- take the lens out as soon as the eye becomes painful or red;
- do not put it back in "just for now" to get home or finish the working day;
- be seen by an eye specialist the same day, not several days later;
- take the case, the solution and the lens packaging with you — the doctor will want them;
- do not try to ride it out on drops left over from a previous episode.
The same caution applies if you have slept in your lenses, rinsed them under the tap, swum in them or worn them beyond their replacement date.
Injuries and chemical splashes
If detergent, lime, solvent, glue, an acid or an alkali has got into the eye, rinse it immediately and for a long time. Do not go looking for a special solution and do not ring anyone first: hold the eye under a gentle stream of clean cool water and rinse for at least twenty minutes, holding the lids apart with your fingers and rolling the eye in every direction. Those first minutes decide more than all the treatment that follows. Powders and lime should be brushed off dry first and rinsed afterwards. You still need to be examined, and it is useful to bring the product packaging with you.
A blow to the eye, a cut eyelid, or glass, a metal shaving or a grinding spark entering the eye is handled the opposite way: rinse nothing and remove nothing. Leave anything embedded where it is, do not press on the eye, do not rub it and do not try to peer at it; cover it with something rigid resting clear of the surface and go to hospital. If the injury happened while using an angle grinder or a hammer without goggles, get it looked at even if the discomfort is slight: a fragment can pass inside the eye almost painlessly.
What ordinary conjunctivitis looks like
The harmless version has a recognisable pattern of its own. The redness is diffuse, spread across the whole white of the eye and strongest near the lids. There is itching, burning, a gritty feeling and discharge — watery when the cause is viral, thick and gluing the lashes together overnight when it is bacterial. And, most important of all, the vision is unaffected and there is no true pain. If wiping the eye clears the fog, that was a film of discharge and not loss of sight.
Viral conjunctivitis often starts in one eye and moves to the other within a day or two, arrives with a cold and with a tender swollen gland in front of the ear. It settles by itself over one to two weeks, and treatment amounts to cool compresses and preservative-free lubricating drops. The allergic kind causes intense itching and swelling, affects both eyes at once and matches a season or contact with an animal. The bacterial kind needs drops prescribed by a doctor.
All of this is highly contagious. While it lasts, use your own towel, wash your hands often, and leave lenses and eye make-up alone; make-up used in the first few days is best thrown away.
Harmless causes that look worse than they are
- A burst blood vessel. A bright red, sharply outlined patch on the white of the eye, like spilt paint. It does not hurt, does not alter vision, and clears over one to two weeks, changing colour like a bruise. If it keeps happening, blood pressure and clotting are worth checking.
- Dry eye. Stinging, a gritty feeling, paradoxical watering, worse in the evening, while driving, on a plane and after long screen sessions. Breaks, humidified air and artificial tears all help.
- Blepharitis. Red, itchy lid margins, flakes and crusts at the roots of the lashes, lids stuck together in the morning. Warm compresses and daily lid hygiene are the mainstay.
- Styes and chalazia. A tender lump on the lid, or the firm painless bead left behind after one.
- An ingrowing eyelash or a speck under the upper lid: a foreign-body sensation, watering and redness on one side only.
- Irritation from smoke, chlorinated water, cosmetics, eye drops or dust.
What not to do
- Do not use decongestant drops "for redness". They remove no cause, only its one visible sign, and they disguise an eye that needed a doctor today. Used regularly, the white of the eye goes redder and redder as soon as each dose wears off.
- Do not use steroid drops without being examined. Corticosteroid drops are genuinely prescribed for some inflammations, but only once a doctor has examined the cornea. In herpes keratitis they let the virus spread and can cost you the eye, and used long term they raise the pressure inside it.
- Do not use someone else's drops, and do not finish off an antibiotic left over from another occasion.
- Do not rub the eye or apply heat to it if there is pain or pus.
- Do not wash the eye out with tea, saliva, breast milk or home-made solutions.
- Do not wear lenses or eye make-up until the redness has gone completely.
Who needs examining even if the eye does not hurt
- Newborns and babies. A red eye with discharge in the first weeks of life is assessed urgently: it can be an infection acquired during birth.
- Young children, if the eye reddens with a temperature, a swollen lid, or the child screws up their eyes against light.
- People with a weakened immune system, on chemotherapy, or on medicines that suppress immunity.
- Anyone with rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel disease or sarcoidosis: in them a red, painful eye that keeps coming back is a typical start to uveitis.
- Anyone who has recently had eye surgery or an injection into the eye.
- Anyone whose redness lasts longer than a week or returns again and again in the same eye.
Online consultation
An online appointment is good at sorting out which of the two groups your case belongs to: the doctor will ask about pain, light, vision and lenses, look at the eye through the camera, judge whether there is discharge and how the redness is distributed, and say plainly whether this can be watched at home or needs an eye specialist today. They can also review anything you have already started putting in, and explain how to look after the lids in blepharitis and dry eye.
What cannot be done through a screen is a slit-lamp examination and staining of the cornea. So with pain in the eye, light sensitivity, reduced vision, an altered pupil, an injury, or redness in a contact lens wearer, an online consultation is not the right route — you need to be seen in person the same day.
This material is for information only and does not replace medical advice.
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