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What is conjunctivitis? | Types | Causes | Symptoms | Treatment | Prevention of infectious conjunctivitis

What is conjunctivitis?

The conjunctiva is a thin mucus membrane covering all the front part of eyeball except the cornea. The conjunctiva is also located on underside of the upper and lower eyelids. It is actually translucent like waxed paper, but it appears white on the eyeball because it lies over the sclera. It looks pink on the eyelids because of the blood vessels located under it.

Conjunctivitis, commonly called "pink eye," is an inflammation of the conjunctiva and is characterized by red, tender, swollen eyes and eyelids.

Types

There are several types of conjunctivitis. The first, infectious conjunctivitis, is caused by a contagious virus or bacteria. Allergic conjunctivitis is the result of allergies to pollen, cosmetics, animals, or fabrics. Chemical conjunctivitis results from irritants like air pollution, noxious fumes, and chlorine in swimming pools.

Causes

A virus that causes conjunctivitis may also cause an upper respiratory infection simultaneously. Epidemic keratoconjunctivitis, caused by adenovirus types 3, 8, and 19, is very contagious and spreads easily. It begins with the feeling you have a foreign body in your eye, followed by pain and redness. Next, the lymph nodes in front of the ear become inflamed. Epidemic keratoconjunctivitis can involve the cornea and may last a month or more. It seldom causes permanent damage or threatens the eyesight. Treatment includes cool compresses and tear substitutes.

Pharyngoconjunctival fever is caused by adenovirus type 3. It is usually milder, and is associated with upper respiratory infections. Hemorrhages may occur in the conjunctiva. Treatment includes cool compresses and tear substitutes.

Herpes simplex conjunctivitis is associated with the herpes virus. The patient may have a cold sore near the eyelids. This form of conjunctivitis is usually harmless and does not involve the cornea. However, recurrent infections can cause damage to the cornea.

Bacterial infections of the conjunctiva are more common in children. Normally, you have lots of bacteria on the skin and even in the eye. When a person's natural defenses aren't strong enough to stop the bacteria from multiplying, conjunctivitis can result. Symptoms are usually mild. This form of conjunctivitis usually gets better on its own. However, if needed, sufferers can use artificial tears and cool compresses to soothe the eyes. Patients may also use a nontoxic topical antibacterial cream to relieve the symptoms.

Conjunctivitis caused by allergies can be the result of cosmetics, clothing, laundry products, pets, or pollens. Allergies are usually more prevalent in the spring or fall. Symptoms include itching, a foreign body sensation, tearing, and sensitivity to light. Allergies and the accompanying irritation can occasionally cause damage to a person's cornea. The first step in the treatment is to remove the cause of the itching. Then the patient can use eye drops and decongestants to relieve the symptoms.

Irritants that can cause pink eye include smoke or dust in the air, chlorine in swimming pools, and salt in seawater. Dry air can also cause the eyes to become red and irritated. Ultraviolet rays from too much sun can cause damage to the cornea and conjunctiva. Wearing contacts too long can also cause an eye irritation. A person's eyes might also get red if he or she stays up too late reading. When people stay up too long, they are too tired to blink often enough for tears to moisten the cornea, and the result is red eyes. Treatment for this type of conjunctivitis includes removing the source of irritation, using artificial tears, and resting the eyes. With treatment, the pink or red eyes should improve in a few hours.

Foreign bodies in the eye or an injury to the eye can also cause conjunctivitis. If foreign bodies stay in the eye, they may scratch the eye. In that case, a doctor should see the patient as soon as possible. Symptoms include the sudden onset of excessive tearing, and difficulty keeping the eye open. A corneal irritation causes more pain and sensitivity to light than an irritation of the conjunctiva does.

Symptoms

Symptoms of conjunctivitis include red, watery eyes, inflamed inner eyelids, blurred vision, a scratchy feeling in the eyes, and a puslike or watery discharge.

If you are experiencing some of the symptoms described here, it does not necessarily mean you have conjunctivitis. However, if you experience one or more of these symptoms, you should contact your eye doctor for a complete exam. Click here for information on emergency or immediate care.

Treatment

If the conjunctivitis is infectious and is caused by bacteria, the patient can use antibiotic eye drops. If bacteria cause the conjunctivitis, pus will most likely be present. Viral conjunctivitis must be fought by the body's immune system. This is true of most cases of conjunctivitis. Viral conjunctivitis will generally clear up on its own. If pain, blurred vision, or severe light sensitivity is also present, the patient should see his or her doctor.

If an allergy or a chemical causes the conjunctivitis, the patient should avoid the cause of the allergy. Patients may use prescription or over-the-counter eye drops to relieve their discomfort.

Prevention of infectious conjunctivitis

To prevent infectious conjunctivitis, people should keep their hands away from their eyes. In addition, they should wash their hands often, especially before and after applying medication. To avoid infection, do not share towels, washcloths, cosmetics, or eye drops with others.