Conjunctivitis is when your conjunctiva becomes inflamed. The conjunctiva is a transparent layer of your eye that protects your eyeball. If it gets infected or irritated, your body sends more blood to the eye to help it heal. This makes the blood vessels in your eye expand, meaning the eye looks pink.
Wondering what causes conjunctivitis? Here's what's happening in the eye itself.
There are three main kinds of conjunctivitis. It's helpful to know the difference between the types, as they can have slightly different symptoms and treatments.
This is the most common type of pink eye in adults and it’s very contagious. It's usually caused by adenoviruses — the same kind of virus that causes the common cold (which is why you're also likely to experience cold‑like symptoms). Viral conjunctivitis tends to clear up on its own within a couple of weeks.
This is more common in kids and is usually caused by bacteria in the conjunctiva. It often leads to redness, irritation and a pus‑like discharge.
If you have allergies to things like pollen, pet dander or dust mites, you might get allergic conjunctivitis. If the eye is irritated by an allergy, it releases substances called histamines, which make your eye's veins swell and your eyes feel itchy. Learn more about hay fever.
Book an eye examWhile there are a few different causes of conjunctivitis, they all share similar symptoms.
People tend to get allergic conjunctivitis in both eyes at the same time, whereas bacterial and viral conjunctivitis typically affect only one eye, but can spread to the other.
These are some of the most common conjunctivitis symptoms seen at our independent clinics in Canada:
A pink eye – This is the 'classic' symptom of conjunctivitis. When your body reacts to an infection, it sends more blood to the affected area; a response known as inflammation. The increase in blood flow causes the tiny blood vessels in your eyes to expand, making them more visible. This is what makes your eyes look pink.
A burning sensation – Inflammation can also make your eye feel warmer. This is because more blood is going to the eye, causing some people to find that their eyelids feel warmer to the touch.
Tearing or watering eyes – If you have conjunctivitis, your eyes may produce more tears than usual. If the pink eye is caused by an allergy, a chemical or something on the surface of the eye, the extra tears can help to flush it out.
Grittiness of the eye – You might notice that you get a gritty feeling in your eye, as if there's something on the surface of your eye. This is usually due to conjunctivitis, which can cause the eye to swell slightly when the conjunctiva becomes inflamed.
Itchy eye – If your conjunctivitis is caused by an allergy, your eye might feel especially itchy. When you have an allergic reaction, your body releases a chemical called histamine which makes blood vessels expand, which can make them feel itchy.
Discharge – You might get a sticky or crusty substance (pus) collecting on your eyelashes. People often find their eyes are stuck together when they wake up. This is particularly common with bacterial conjunctivitis.
Conjunctivitis is probably the most common cause of eye‑related visits to the ER in Canada. In a study conducted in Ontario, it was the top eye‑related reason people went to the hospital.
The greatest risk with conjunctivitis is how contagious it can be (particularly the viral form). It's common for pink eye to spread in schools, workplaces, and other places where people spend time close to each other.
Book an eye examSo, what causes conjunctivitis? There are several things that can irritate your conjunctiva and lead to pink eye. Here are the most common causes we see at our stores in Canada.
Most cases of pink eye are caused by viruses, usually the same ones behind colds, like adenoviruses. If that’s the cause, you’ll probably get cold‑like symptoms, too. Other viruses linked to pink eye include herpes, chicken pox and COVID‑19.
Some bacteria that normally live on your skin or in your body can grow too much and cause pink eye. It’s more common in children than adults.
Pollen, pet hair, and dust mites can trigger an allergic reaction that causes pink eye. This often leads to swelling, itching, and redness.
Things like shampoo, cleaning products or eye makeup can irritate your eyes and lead to pink eye.
Fungal conjunctivitis is rare, but it can happen. It’s usually caused by fungi getting into the eye through contact or trauma, dirty contact lenses, or plant material.
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Some types of conjunctivitis often improve on their own within one to two weeks. However, not all red or irritated eyes are caused by conjunctivitis, and some forms require treatment.
If your symptoms are uncomfortable, worsening, affecting your vision or not improving, speak with an optometrist, family doctor, nurse practitioner or pharmacist. A health professional can assess your symptoms, examine your eyes when needed, confirm the cause, and recommend appropriate management to help relieve discomfort.
Book an eye examAt Specsavers, independent optometrists will decide how to treat conjunctivitis depending on your symptoms, how you're feeling and the underlying cause (if known).
In some cases, conjunctivitis can clear up by itself within a couple of weeks. However, sudden vision changes, significant pain, light sensitivity or symptoms in only one eye that are severe should be assessed promptly, and in these cases, it’s recommended to seek treatment.
Many mild cases of conjunctivitis can be managed with supportive care and self‑care measures.
If you wear contact lenses, it’s best not to irritate your eyes any further, so avoid wearing them while you have symptoms and wear your glasses instead. Any contact lenses worn while the infection was active should be discarded and contact lens cases cleaned or replaced.
Conjunctivitis can make your eyes itchy and sore, so it's natural to want to rub them. But this won't resolve the issue and can cause more damage and irritation to your eyes.
Use warm water and cotton pads to gently clean sticky eyelids and lashes. Avoid soaps or chemicals – warm water is usually enough.
If pollen, pet hair or dust mites trigger your conjunctivitis, try to avoid them. Keep pets out of the bedroom and clean regularly to reduce dust mites.
In Canada, a range of over the counter (OTC) treatments that can help relieve conjunctivitis symptoms are available.
Commonly taken as anti‑allergen eye drops, helping to reduce itching and redness by blocking histamine.
Both warm and cold eye compresses can help with relieving pink eye discomfort. You place them over your eyelids, and this can reduce symptoms of itchiness, soreness and inflammation. Warm or cool compresses can help relieve discomfort. Commercial eye masks are available in many pharmacies and optical stores, including Specsavers.
Eyelid cleansing wipes or solutions that you apply with a cotton pad are available at pharmacies and optical retailers, including Specsavers. You can use these wipes or solutions to gently remove built‑up discharge and crust on your eyelashes.
If your conjunctivitis symptoms aren't going away by themselves or you’re experiencing sudden vision changes, significant pain, light sensitivity, or symptoms that are severe, seek treatment as these should be assessed promptly.
If bacterial conjunctivitis is confirmed, prescription antibiotic eye drops or ointment may be recommended. Always finish the full course, even if you start to feel better. Only take antibiotics prescribed by a healthcare provider.
Most viral pink eye clears up on its own. But if caused by certain viruses, such as herpes viruses, prescription antiviral medication may be necessary.
If your conjunctivitis is caused by an autoimmune disorder (this is quite rare), then your physician may prescribe you immunosuppressants. These stop your body's immune system from attacking itself.
Antibiotic eye drops help treat bacterial infection. As the infection improves, redness and discharge typically decrease. A range of eye drops is offered at Specsavers stores in Canada
You can lower your risk of getting conjunctivitis by using a few simple preventive measures.
If you already have viral or bacterial conjunctivitis, these steps can also help avoid passing it on to others.
Viral conjunctivitis spreads easily, so a few days off work or school might help stop it passing on, especially in young children.
Wash your hands often and avoid touching your eyes with unwashed hands, sharing towels or close contact with others. This helps stop pink eye spreading, especially during an outbreak.
Antihistamines help, but it’s best to avoid triggers. Keep pets out of the bedroom, clean often, and during pollen season, close windows and stay in on high pollen days.
Throw away old eye makeup, wear eye protection when using chemicals, and use mild products in the shower, rinsing any soap suds away quickly.
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If your child has pink eye, check with their school/daycare nurse and a healthcare provider about whether they can attend. In some Canadian provinces, kids are required to stay home from school if they have viral conjunctivitis.
Some types of conjunctivitis can improve on their own within one to two weeks. Viral conjunctivitis usually lasts closer to two weeks, while bacterial conjunctivitis usually clears up in about seven to 10 days.
However, not all red or irritated eyes are caused by conjunctivitis, and some forms require treatment. If your symptoms are uncomfortable, worsening, affecting your vision or not improving, it’s recommended to speak with an optometrist, family doctor, nurse practitioner or pharmacist. A health professional can assess your symptoms, examine your eyes, confirm the cause and recommend appropriate treatment.
Yes, bacterial and viral conjunctivitis are highly contagious. They are easily spread through coughs, sneezes and physical contact. It’s important to keep your mouth and nose covered when sneezing or coughing, regularly wash your hands and avoid sharing towels and other items so you don’t pass it on to others.
There are many ways to get conjunctivitis, depending on the type. Bacterial and viral conjunctivitis (which are especially common) are often spread through coughing, sneezing, physical contact or through sharing things like towels. You get allergic conjunctivitis by being exposed to an allergen that affects you.
Conjunctivitis usually stays contagious for as long as you have symptoms, especially if you have any kind of eye discharge. Viral conjunctivitis can be contagious for 1‑2 weeks until symptoms subside, whereas bacterial conjunctivitis is generally contagious until 24 hours after starting appropriate antibiotic treatment. Allergic conjunctivitis is not contagious.
It's not usually necessary to go to the ER if you have pink eye. Some types of conjunctivitis can improve on their own within one to two weeks. However, not all red or irritated eyes are caused by conjunctivitis, and some forms require treatment.
If your symptoms are uncomfortable, worsening, affecting your vision or not improving, it’s recommended to speak with a health professional, like an optometrist, family doctor, nurse practitioner or pharmacist.
Conjunctivitis is when your conjunctiva is irritated or infected — meaning the issue is specifically affecting this part of your eye. An irritated eye can have many other causes or affect different parts of the eye.
If someone you live with has pink eye, there are a few things you can do to avoid it. First, regularly wash your hands with soap and water. Don't share any items that you touch or use on your face (such as hand towels in the bathroom). If they are coughing or sneezing without covering their nose and mouth, remind them that this can spread the infection.
Some types of conjunctivitis often improve on their own within one to two weeks. However, if your symptoms are uncomfortable, worsening, affecting your vision or not improving, it’s recommended to speak with an optometrist, family doctor, nurse practitioner, or pharmacist. They’ll assess your symptoms and recommend appropriate treatment.
CAO (2023) Conjunctivitis (pink eye) Available at: https://opto.ca/eye‑health‑library/conjunctivitis‑pink‑eye
Cleveland Clinic (2024) Pink eye Available at: https://my.clevelandclinic.org/health/diseases/pink‑eye‑conjunctivitis
Hashimia, F. et al (2024) Conjunctivitis Available at: https://www.ncbi.nlm.nih.gov/books/NBK541034/
Healthlink BC (2022) Pink eye Available at: https://www.healthlinkbc.ca/healthwise/pink‑eye
Mayo Clinic (2025) Pink eye Available at: https://www.mayoclinic.org/diseases‑conditions/pink‑eye/symptoms‑causes/syc‑20376355
Medical News Today (2023) How long is pink eye contagious? Available at: https://www.medicalnewstoday.com/articles/321551
Nanji, K., et al. (2023) Profile of eye‑related emergency department visits in Ontario – a Canadian perspective. Available at: https://www.nwhu.on.ca/for‑professionals/for‑schools/contagious‑illness‑in‑schools‑and‑childcare‑centres/
Northwestern Health Unit (2024) Contagious Illness in Schools and Childcare Centres. Available at: https://www.nwhu.on.ca/for‑professionals/for‑schools/contagious‑illness‑in‑schools‑and‑childcare‑centres/
Solando, D., et al. (2023) Viral conjunctivitis Available at: https://www.ncbi.nlm.nih.gov/books/NBK470271/
This is an inflammation of the iris and the uvea, which is the coloured part of the eye. It's often easy to treat, but could cause vision loss if not dealt with promptly.
This is when the edges of your eyelids get inflamed due to a skin problem or infection. It can also make the whites of your eyes look pink or red.
A corneal ulcer is a painful sore that develops on the outer surface of your eye. These ulcers can cause eye inflammation and redness. They're more common among people who wear contact lenses.
A corneal abrasion is when there's a scratch on the front of your eye. It often causes red eyes, discomfort and sensitivity to light.
There are quite a few eye conditions that can give you red or bloodshot eyes. In different ways, they can cause inflammation of the whites of the eyes, your eyelids or the conjunctiva.
Find the symptoms, causes and treatments of a whole range of eye conditions and vision problems.
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Your eyes can actually tell us a lot about your general health.
Learn about eye healthIf you have any concerns about your eye health, contact or visit your local optometrist immediately – even if you do not have an appointment.
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