Eye conditions

What is conjunctivitis?

Conjunctivitis, often called “pink eye”, is one of the most common eye conditions. It’s inflammation of the conjunctiva, the thin, clear layer that lines the inside of your eyelids and covers the white of your eye.

When the conjunctiva becomes irritated or inflamed, your eye can look red or pink, feel itchy, gritty or sore, and produce a sticky discharge. Conjunctivitis can be caused by a virus, bacteria, an allergy such as hay fever, or an irritant like chlorine or smoke, and the right treatment depends on the cause.

Some types are contagious and some aren’t, so it’s worth getting your eyes checked if you’re not sure. Our director, Amar-Kaash Gandecha, is a qualified therapeutic optometrist who can diagnose eye conditions and prescribe treatment, often without the need for a hospital referral.

Red, irritated eye with conjunctivitis

Know the signs

Symptoms, causes and risk factors

Symptoms

  • Red or pink eyes, including redness inside the eyelids
  • Itching, burning or a gritty feeling, like sand in your eye
  • Sticky discharge and crusty eyelids, especially when you wake up
  • Watery eyes
  • Puffy, swollen eyelids
  • Sensitivity to bright light
  • In children: rubbing their eyes a lot, sometimes with sneezing or a runny nose

Causes

Conjunctivitis happens when something irritates or infects the conjunctiva:

  • Viruses: often the same viruses that cause colds
  • Bacteria: which can cause more severe symptoms
  • Allergies: such as pollen, dust or pet hair
  • Irritants: such as chlorine, smoke or chemicals
  • Contact lenses: a reaction to lens wear (giant papillary conjunctivitis)

Risk factors

Some things make conjunctivitis more likely:

  • Close contact with someone who has infective conjunctivitis
  • Hay fever or other allergies
  • Wearing contact lenses for long periods or sleeping in them
  • Untreated blepharitis, which raises the risk of eye infections
  • Sharing towels, pillows, make-up or eye drops

Causes

Types of conjunctivitis

There are several types of conjunctivitis. Knowing which one you have matters, because it affects whether it’s contagious and how it’s treated.

Contagious

Viral

Often caused by the same viruses as colds and other respiratory infections. It spreads easily and usually clears up on its own.

Contagious

Bacterial

Caused by bacteria. Symptoms can be more severe, and it may need antibiotic treatment.

Not contagious

Allergic

Triggered by allergens such as pollen, dust or pet hair, and often comes with other allergy symptoms like sneezing.

Not contagious

Chemical

Caused by irritants such as chlorine, smoke or chemicals. Flush the eye with clean water straight away.

Not contagious

Giant papillary (GPC)

A type of allergic conjunctivitis linked to contact lenses. It causes itching, mucus and difficulty wearing lenses.

Urgent

Neonatal

Affects babies in their first month, most often from an infection passed on at birth. It needs treating quickly, as it can cause permanent eye damage.

Allergies

Hay fever and allergic conjunctivitis

For most people, allergic conjunctivitis is part of hay fever. Pollen lands on the surface of the eye and triggers the release of histamine, which causes itching, burning, watering, redness and puffy eyelids. It can be seasonal or happen all year round.

How to tell it’s allergic: both eyes are usually affected and symptoms come on quickly. The insides of the eyelids look red and sore, and your eyes may burn but aren’t usually painful. Hay fever affects the whole body, so if only one eye is irritated, it’s unlikely to be the cause. If one eye stays irritated for more than 1 to 2 days, speak to your optometrist.

Easing symptoms:

  • Avoid pollen where you can: keep windows closed, especially when pollen peaks from mid-May to July.
  • Wear glasses or wraparound sunglasses to keep pollen out of your eyes.
  • If you wear contact lenses, daily disposables stop pollen building up.
  • Use a cool compress or soothing eye mask, and try not to rub your eyes.
  • Ask us about anti-allergy eye drops and antihistamine tablets. Some eye drops can’t be used with contact lenses, so check first.

Read more in our guide to how hay fever affects your eyes.

What works

Conjunctivitis treatment

Treatment depends on the type of conjunctivitis. Some types clear up on their own, while others need medicine. We can examine your eyes, find the cause and, where needed, prescribe treatment.

Viral and bacterial conjunctivitis

Viral conjunctivitis usually clears up on its own. To ease discomfort while it heals:

  • Cool compresses: hold a clean, cool, damp cloth over your eyes to reduce swelling and itching. Use a fresh cloth each time.
  • Artificial tears: lubricating eye drops soothe dry, irritated eyes and help wash away discharge. Choose preservative-free drops if you use them often.
  • Rest and hygiene: keep your eyes clean, avoid touching them and wash your hands often.

Bacterial conjunctivitis often needs treatment to clear the infection:

  • Antibiotic eye drops or ointment: finish the full course, even if your eyes feel better sooner.
  • Stop wearing contact lenses until the infection has completely cleared.
  • Follow-up: if your symptoms haven’t improved within a few days of starting treatment, come back and see us.
Using eye drops for conjunctivitis

Allergic and chemical conjunctivitis

Allergic conjunctivitis is treated by easing symptoms and avoiding triggers:

  • Antihistamine eye drops relieve itching, redness and swelling by blocking histamine.
  • Avoid allergens where you can, for example staying indoors when the pollen count is high, using air filters or avoiding pet hair.
  • Antihistamine tablets can help if you also have a blocked or runny nose or sneezing.
  • Cool compresses soothe itching and swelling.

Chemical conjunctivitis needs action straight away. Rinse your eyes with clean, lukewarm water or saline for at least 15 minutes, then get your eyes checked as soon as possible. You may need medicated eye drops and follow-up appointments to make sure there’s no lasting damage.

How to stop conjunctivitis spreading

1

Wash your hands

Wash your hands regularly with warm, soapy water, especially after touching your eyes.

2

Don't rub your eyes

Rubbing spreads infection and makes irritation worse.

3

Keep things to yourself

Don't share towels, pillows, make-up or eye drops.

4

Wash bedding and cloths

Wash pillowcases and face cloths in hot water and detergent.

5

Catch sneezes

Cover your mouth and nose when you sneeze, and put used tissues in the bin.

Opticare optometrist checking a patient's eyes

Get it checked

When to see an optometrist

To diagnose conjunctivitis, we’ll examine your eyes and ask about your symptoms, anything you may have been exposed to and your general health. Book an appointment if:

  • You're not sure what's causing your red or sore eyes
  • Only one eye is irritated and it hasn't settled after 1 to 2 days
  • Your symptoms haven't improved within a few days of starting treatment
  • You wear contact lenses and your eyes are red or uncomfortable

Get help straight away if:

  • A chemical has splashed in your eye (rinse it for at least 15 minutes first)
  • A baby in their first month has red or sticky eyes
  • You have severe eye pain, your vision changes or bright light really hurts your eyes

Lens wearers

Conjunctivitis and contact lenses

Contact lenses can make conjunctivitis more likely and can make it worse while you have it, so a few extra precautions help.

Tips for lens wearers

  • Stop wearing your lenses until conjunctivitis has completely cleared, and wear your glasses instead.
  • Don’t sleep in your lenses unless your optometrist has said it’s safe, and take them out on long flights.
  • In hay fever season, daily disposable lenses stop pollen building up.
  • Check before using anti-allergy eye drops, as some can’t be used with contact lenses.

Giant papillary conjunctivitis (GPC)

GPC is an allergic reaction linked to contact lens wear. It causes itching, mucus and difficulty wearing your lenses. It’s usually caused by protein deposits building up on lenses, or wearing lenses for a long time without replacing them. To help prevent it:

  • Replace your lenses as often as recommended
  • Keep up good cleaning habits
  • Consider daily disposables if your eyes are prone to irritation

FAQs

Frequently asked questions about conjunctivitis

Conjunctivitis, often called “pink eye”, is inflammation of the conjunctiva, the thin, clear layer that lines the inside of the eyelids and covers the white of the eye. It can make your eyes red or pink, itchy, gritty and sticky.

The main types are viral, bacterial, allergic and chemical. There’s also giant papillary conjunctivitis (GPC), an allergic reaction linked to contact lenses, and neonatal conjunctivitis, which affects babies in their first month. See types of conjunctivitis.

Viral and bacterial conjunctivitis are contagious. Allergic, chemical and giant papillary conjunctivitis aren’t. To stop infective conjunctivitis spreading, wash your hands regularly, avoid rubbing your eyes and don’t share towels, pillows, make-up or eye drops.

Your optometrist will examine your eyes and ask about your symptoms, anything you may have been exposed to and your general health.

It depends on the type. Viral conjunctivitis usually clears on its own, helped by cool compresses and lubricating drops. Bacterial conjunctivitis may need antibiotic drops or ointment. Allergic conjunctivitis is treated with antihistamine drops or tablets and avoiding triggers. Chemical conjunctivitis needs rinsing with clean water for at least 15 minutes, then an urgent eye check.

Yes. Allergic conjunctivitis is often part of hay fever. It usually affects both eyes, causing itching, watering, redness and puffy eyelids. If only one eye is affected, hay fever is unlikely to be the cause.

No. Stop wearing your lenses until the conjunctivitis has completely cleared, and wear your glasses instead. Check with us before using anti-allergy eye drops, as some can’t be used with lenses.

Yes, especially infective or chemical conjunctivitis, although infection can spread to the other eye. Allergic conjunctivitis usually affects both eyes. If one eye stays irritated for more than 1 to 2 days, see your optometrist.

Yes. Neonatal conjunctivitis affects babies in their first month and is most often caused by an infection passed on at birth. It needs treating quickly, so get a baby with red or sticky eyes checked straight away.

Untreated blepharitis can increase the risk of eye infections, including conjunctivitis. Keeping your eyelids clean helps. See blepharitis.

Medically reviewed by Amar-Kaash Gandecha, BSc(Hons) MCOptom DipTp(IP), Prof Cert Glauc, Director and Optometrist. Last reviewed 14 August 2026.

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Conjunctivitis