What is conjunctivitis (pink eye)?

Conjunctivitis is the term used to describe inflammation of the conjunctiva—the thin, filmy membrane that covers the inside of your eyelids and the white part of your eye (sclera). Conjunctivitis is most commonly referred to as “pink” eye.

The conjunctiva, which contains tiny blood vessels, produces mucus to coat and lubricate the surface of your eye. When the conjunctiva becomes irritated or inflamed, the blood vessels become larger and more prominent, making your eye appear red. Conjunctivitis may occur in one or both eyes.

Dr. Manvi P. Maker
Ophthalmologist (Eye Specialist)

Pink eye (or conjunctivitis) is an inflammation of the clear covering over the white part of the eye. It may result in eye redness, discharge, eyelid sticky sensation, foreign body sensation, tearing and pain. It can be caused by a bacterial infection, viral infection or it can be an allergic reaction.

Most forms of conjunctivits will resolve on their own, but other forms can be more serious and require attention. It is important to make an appointment with your eye doctor who can diagnose the source of the conjunctivitis and provide appropriate treatment.

Dr. Michael H. Reynard, MD
Ophthalmologist (Eye Specialist)

Conjunctivitis is inflammation of the surface of the eye. Individuals with conjunctivitis have redness of the eye that is often accompanied by tearing or purulent discharge. There are many causes for conjunctivitis. They include infection, allergy, exposure to toxic agents, and dryness of the eye. Conjunctivitis is also called "pink eye," but this lay term is commonly used to indicate infection of the eye causing redness. Infectious agents such as bacteria and viruses can cause conjunctivitis.

Epidemic conjunctivitis pink eye is the most common type of conjunctivitis caused by the virus, adenovirus. It is a contagious eye condition that happens when the conjunctiva becomes inflamed. The conjunctiva is a transparent membrane that lines the inside of the eyelid and covers the whites of the eye. Conjunctivitis can be caused by allergy, dry eyes, irritation, a virus, or bacterial infection known as “pinkeye.” Pinkeye is common in childcare centers or crowded classrooms, but both viral and bacterial conjunctivitis are contagious from exposure to someone with this disease. Symptoms of conjunctivitis include redness, tearing, a “gritty” feeling when blinking, itching, burning, and swelling of the eye and eyelid. 

With bacterial conjunctivitis, there is usually a thick, yellow mucus-like discharge that crusts over the eye and glues the eyelid together. Viral conjunctivitis usually affects both eyes, while bacterial pinkeye may only affect one eye. Viral conjunctivitis transmits to other people very quickly and can cause an epidemic outbreak. Allergic conjunctivitis leaves the eyes red, itchy, and watery but there is no thick yellow-green discharge. Epidemic conjunctivitis pink eye is uncomfortable, but it is unlikely to cause permanent damage to your eyes. However, rare types of conjunctivitis can lead to blindness if left untreated.

If you suspect conjunctivitis, contact your doctor to determine the cause. Only your doctor can determine which type of conjunctivitis you have, and the treatment is different depending on if it’s viral or bacterial.

Dr. David R. Demartini, MD
Ophthalmologist (Eye Specialist)

Epidemic keratoconjunctivitis (commonly referred to as "pink Eye") is cuased by a very contagious virus that easily spred. Commonly, slight contact with infected tears or other nose or throat fluids leads to easy transmission of this infection. Most patients have a short incubation period before they show symptoms of about five days. Their usual symptoms ar redness, mild swelling, and copious tears. The discharge is usually minimally thick or discolored. These symptoms persist for about 7-10 days then they decrease. Some patients may get this infection to invade the cornea which can cause mild to moderate decrease in vision and light sensitivity. These corneal lesions can perist for weeks to years depending on the patient. They can be the worst problem of "pink eye" because they can cause permanent vision loss.

When doctors talk about pinkeye, they usually mean bacterial conjunctivitis. However, many things can cause the eye to become red or inflamed, including viruses, allergies, contact lenses or air pollutants.

Continue Learning about Bacterial Eye Infections

How quickly will bacterial eye infections clear up?
Honor Society of Nursing (STTI)Honor Society of Nursing (STTI)
As with many bacterial eye infections, the infection clears up quickly with treatment. Eye drops and...
More Answers
What are the treatment options for bacterial eye infections?
Diana MeeksDiana Meeks
The type of treatment for bacterial eye infections is dependent on the type of infection you have. C...
More Answers
Does trachoma affect children differently than adults?
Diana MeeksDiana Meeks
Because adults tend to have better personal hygiene practices and are less likely to touch their eye...
More Answers
What's the difference between pink eye and conjunctivitis?
Michael X. RepkaMichael X. Repka
There is substantial overlap between pink eye and conjunctivitis. Pink eye is an infectious form of ...
More Answers

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.