Like all medical terms which end in “-itis", conjunctivitis describes a type of inflammation. It affects the conjunctiva, which is a thin membrane over the top of the sclera and over the inside of the eyelids.
Conjunctivitis is also called Pink Eye or Red Eye. It can be caused by an allergy, bacteria, a virus, or a chemical splashed into the eye. Mild cases can be caused by something which gets into the eye and irritates it, such as smoke or dust. When it is caused by bacteria or viruses it is contagious.
Conjunctivitis causes are not always obvious and your eye doctor may need to do a slit lamp examination to diagnose the cause. Sometimes a laboratory test is needed.
Irritation, redness, and excessive tearing are the most common symptoms. Depending on the cause, there are also other symptoms:
- Allergic conjunctivitis has a stringy discharge and different degrees of pinkness or redness. When severe it is very itchy and the eyelids may swell.
- Bacterial conjunctivitis gives different symptoms depending on which particular bacterium is the cause. There may be a gritty feeling in the eyes, crusting of the eyelids due to a gray or yellow discharge, and sometimes moderate pain. The infection may be in one eye only at first but will usually spread to the other eye.
- Viral conjunctivitis may also begin in one eye and later spread to the other. There is a watery discharge and this type is often related to infection in the respiratory tract, such as a cold or throat infection.
- Chemical conjunctivitis makes the eyes red and can be very painful, especially when you look upwards or downwards. Any chemical splashed into the eyes tends to pool inside the lower lids but may also be caught inside the upper lid. Typically there is no discharge. A caustic chemical (too acid or too alkaline) can cause the death of surface eye cells and the sclera may look white not because of any lack of problem, but because the blood vessels have been closed down.
Treatment varies according to the cause.
- For allergic conjunctivitis, if the allergen is unknown and therefore cannot be removed, symptoms can be treated with cool water over the eyes and face to help shrink the tiny blood vessels. Artificial tears help in mild cases and prescription eyedrops are needed for more severe cases, either steroid or non-steroid.
- Bacterial conjunctivitis typically needs no treatment, but heals up within a week by itself. Antibiotic eyedrops are sometimes prescribed anyway, and they will speed the recovery, reducing it from about five days to three.
- There are no specific treatments for viral conjunctivitis and it is allowed to run its course. It will usually resolve within three to four weeks. Symptoms can be soothed with prescription or non-prescription eyedrops and if there is a related infection in the airway, antibiotic eyedrops are used.
- The burns of chemical conjunctivitis can be a sight-threatening emergency, as they may cause scars on the eye surface within the visual field. To remove the chemical, a saline solution is typically used (that is, a salt solution of the same strength as the body’s natural fluids). Then a topical steroid is used for healing.
Mild cases of conjunctivitis are quite common and usually resolve with no lasting problem. Treatments of the more severe cases are usually successful.
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