01 · Overview
The short version
Red eye is a symptom, not a diagnosis
Dryness, allergies, infection, a scratched cornea, contact lens irritation, chemicals, and glaucoma can all make the eye look red. The right treatment depends on the cause.
Pain or vision change makes it more urgent
Redness with eye pain, blurry vision, light sensitivity, headache, nausea, or a sudden change in sight should not be watched at home for long.
Contact lenses change the risk
If you wear contacts and your eye is red, painful, or light-sensitive, take the lenses out and get prompt advice. Lens wear can hide or worsen a corneal problem.
Simple care can help mild irritation
Cool compresses, artificial tears, and avoiding rubbing may ease mild dryness or irritation, but they do not replace care when warning signs are present.
02 · Care guidance
When to get help
Emergency help
- Call 911 or go to the ER now if red eye comes with sudden vision loss, severe eye pain, chemical exposure, a deep injury, a new droopy face or weakness, or signs of anaphylaxis such as trouble breathing or swelling of the lips or tongue.
Get advice promptly
- Get same-day or next-day care if you have red eye with moderate pain, light sensitivity, pus-like discharge, a foreign body sensation that does not improve, contact lens use, fever, or redness in only one eye that is worsening.
- Seek urgent eye care if you had recent eye surgery, a blow to the eye, or symptoms of angle-closure glaucoma such as eye pain, headache, blurry vision, halos around lights, nausea, or vomiting.
If the redness is mild, both eyes are affected, and you feel otherwise well, try gentle self-care and arrange a routine visit if it does not improve within a few days or keeps coming back.
03 · Red Eye
What the redness is actually telling you
Redness usually means the eye surface is irritated or inflamed, but the reason can range from minor dryness to a problem that needs urgent treatment.
The white part of the eye turns red when surface blood vessels widen or when the tissues of the eye are inflamed. That can happen with dryness, allergies, viral or bacterial conjunctivitis, a scratched cornea, a foreign body, or chemical irritation. Sometimes the eyelid or nearby skin is the source of the problem, not the eye itself.
The pattern matters. Mild itching and watering often fit irritation or allergy. Thick discharge or crusting can point toward infection. Pain, light sensitivity, or blurry vision make a simple cause less likely and raise the need for an eye exam.
- Both eyes and itching often fit allergy or irritation.
- One red eye is more concerning when it is painful or worsening.
- Discharge, crusting, or blur can change the urgency.
04 · Red Eye
Common causes and the clues that fit them
The most likely causes are often irritation, allergy, or conjunctivitis, but contact lenses, scratches, and chemicals make the situation more serious.
Dry eyes, screen time, smoke, wind, chlorine, and eye rubbing can leave the eyes red and gritty. Allergies often cause itching, tearing, and redness in both eyes. Viral conjunctivitis is common and can spread easily. Bacterial conjunctivitis is more likely to cause pus-like discharge, although symptoms can overlap enough that an exam may be needed.
A red eye after contact lens use, a scratch, or getting something in the eye needs extra caution because the cornea can be involved. Eye pain with nausea, halos, and blurred vision can point to a pressure problem such as angle-closure glaucoma. That situation needs urgent treatment rather than waiting for it to settle.
- Itching and both eyes can fit allergy.
- Discharge can happen with conjunctivitis, but not every discharge means bacteria.
- Contacts, injury, or chemical exposure raise the risk of a corneal problem.
05 · Red Eye
Symptoms that should not wait
Some red eyes need same-day care because vision can be affected quickly, especially when pain, vision change, injury, or contact lens use is part of the picture.
Get urgent help if redness comes with significant pain, light sensitivity, blurry vision, a sudden change in sight, a foreign body that will not wash out, or a chemical splash. A blow to the eye, a penetrating injury, or a very painful headache with nausea is also concerning. These patterns can mean the problem is deeper than surface irritation.
If you wear contact lenses and your eye is red and painful, do not keep wearing the lenses. Contact lens use can raise the risk of a corneal infection, which can worsen quickly and needs prompt treatment. Recent eye surgery is another reason not to wait, because postoperative problems need a clinician’s review.
- Pain plus blur or light sensitivity needs prompt evaluation.
- Chemical splash or eye trauma is an emergency.
- Contact lens wear raises the concern for corneal infection.
06 · Red Eye
What is reasonable to try at home
For mild redness without warning signs, gentle care can reduce irritation while you watch for improvement.
Cool compresses, lubricating artificial tears, and a break from contact lenses, eye makeup, smoke, and chlorine can help mild redness that seems like dryness or irritation. Wash your hands before touching your eyes, and do not rub them, because rubbing can make redness worse. If you need drops often, preservative-free artificial tears are usually easier on the eye than drops that sting.
Be careful with drops that promise to quickly “get the red out.” They may briefly mask the problem and can lead to rebound redness with repeated use. Do not use someone else’s eye drops or leftover prescription drops for a new eye problem. If symptoms are not clearly improving in a few days, a routine visit is reasonable.
- Artificial tears can soothe dryness.
- Rubbing can make irritation worse.
- Do not use leftover or borrowed prescription eye drops.
07 · Red Eye
When infection might be involved
Some causes of red eye are contagious, so handwashing and not sharing eye items matter while the cause is still unclear.
Viral and bacterial conjunctivitis can both cause red eye, tearing, and discharge, and they can be hard to tell apart without an exam. Some cases begin in one eye and spread to the other. Because some types of pink eye spread easily, careful handwashing and not sharing towels, pillows, cosmetics, or eye products are important.
Fever, worsening eyelid swelling, severe pain, or trouble moving the eye suggest the problem may be deeper than simple conjunctivitis. That is not a situation for home treatment alone. If infection seems likely, an exam helps decide whether supportive care is enough or whether prescription treatment is needed.
- Wash hands often and avoid touching the eyes.
- Do not share towels, washcloths, or cosmetics.
- Worsening swelling or trouble moving the eye needs prompt review.
08 · Red Eye
What an eye visit may involve
An exam can show whether the redness is on the surface, in the cornea, from pressure, or related to injury.
A clinician may ask when the redness started, whether you wear contacts, whether there was an injury or chemical exposure, and whether the eye is painful, blurry, or sensitive to light. The exam may include checking vision, looking closely at the cornea and eyelids, and sometimes measuring eye pressure or using drops to examine the back of the eye.
This matters because the treatment depends on the source. Dryness and allergy may need supportive care, conjunctivitis may need specific treatment depending on the cause, and glaucoma or a corneal injury needs urgent eye care. Even when the eye only looks moderately red, the exam can uncover problems that are not safe to ignore.
- Bring your contact lens details if you wear them.
- Tell the clinician if one eye sees worse than the other.
- Mention chemicals, swimming, makeup, or trauma.
09 · FAQ
Questions people ask
Can red eye go away on its own?
Yes, mild irritation sometimes improves on its own with rest and avoiding the trigger. But redness that is painful, lasts more than a short time, affects vision, or keeps coming back should not be ignored. Persistent or repeated red eye can be a clue to an untreated eye problem that needs an exam.
Should I stop wearing contact lenses?
Yes, take out your lenses if your eye is red, painful, itchy, or sensitive to light. Do not put them back in until the eye feels normal and you know it is safe. If symptoms are more than mild, get checked promptly because lens wear can hide a corneal problem.
Can I use over-the-counter eye drops?
Lubricating drops can help mild dryness or irritation. Be careful with “get the red out” drops, because they may briefly mask symptoms and can worsen rebound redness with repeated use. Do not use drops that are meant for another person or that were prescribed for a different problem.
Is red eye contagious?
Sometimes. Viral and bacterial conjunctivitis can spread, especially through hands, towels, pillowcases, cosmetics, and shared items. Allergic and dry-eye redness are not contagious. If you have drainage or crusting, be extra careful with hygiene until you know the cause.
What if the redness started after swimming?
Chlorine and other pool chemicals can irritate the eyes and cause temporary redness and burning. Rinse with clean water or saline, use lubricating drops if needed, and avoid rubbing. If pain, blur, or light sensitivity lasts, it could be more than irritation and should be checked.
Does a red eye always need antibiotics?
No. Many red eyes are from irritation, allergies, or viral infection, and antibiotics do not help those causes. Antibiotic drops may be used when a bacterial infection is suspected, but the right treatment depends on the exam. Using antibiotics without a clear reason can be unhelpful.
10 · References
References and supporting evidence
These sources support the points identified below. Source checking is not clinical approval.
- S1: Eye DiseasesMedlinePlus / U.S. National Library of Medicine
Explains that conjunctivitis can cause red itchy eyes and that some types spread easily; also supports regular eye exams and urgent attention for sudden vision change, eye pain, double vision, fluid from the eye, or swelling.
- S2: GlaucomaMedlinePlus / U.S. National Library of Medicine
Explains that sudden painful red eye with blurry vision or nausea can be a sign of angle-closure glaucoma and needs immediate medical care; also supports that glaucoma may have no early symptoms and can lead to vision loss without treatment.
General information, not a diagnosis. This guide is not a substitute for care from a qualified healthcare professional. For an emergency, call 911 in the US or your local emergency number. Illustrations are conceptual and are not diagnostic images.