2. szöveg
Infectious Conjunctivitis
Infectious conjunctivitis is inflammation of the conjunctiva usually caused by viruses or bacteria. A variety of microorganisms may infect the conjunctiva (the membrane that lines the eyelid and covers the white of the eye). The most common organisms are viral, particularly those from the group known as adenoviruses. Bacterial infections are less frequent.
Both viral and bacterial conjunctivitis are quite contagious, easily passing from one person to another, or from a person's infected eye to the uninfected eye. Fungal infections are rare and occur mainly in people who use corticosteroid eye drops for a long time or have eye injuries involving organic matter, such as plants or dirt. Newborns are particularly susceptible to eye infections, which they acquire from organisms in the mother's birth canal.
Severe infections may scar the conjunctiva, causing abnormalities in the tear film. Sometimes, severe conjunctival infections spread to the cornea (the clear layer in front of the iris and pupil).
Symptoms
When infected, the conjunctiva becomes pink from dilated blood vessels, and a discharge appears in the eye. Often the discharge causes the person's eyes to stick shut, particularly overnight. This discharge may also cause the vision to blur. Vision improves when the discharge is blinked away. If the cornea is infected, vision also blurs but does not improve with blinking. Sometimes the eye feels irritated, and bright light may cause discomfort. Very rarely, severe infections that have scarred the conjunctiva lead to long-term vision difficulties.
Viral conjunctivitis differs from bacterial conjunctivitis in the following ways:
- Eye discharge tends to be watery in viral conjunctivitis and thicker white or yellow in bacterial conjunctivitis.
- An upper respiratory infection increases the likelihood of a viral cause.
- A lymph node in front of the ear may be swollen and painful in viral conjunctivitis but is usually not in bacterial conjunctivitis.
These factors, however, cannot always accurately differentiate viral conjunctivitis from bacterial conjunctivitis.
Diagnosis
Doctors diagnose infectious conjunctivitis by its symptoms and appearance. The eye is usually closely examined with a slit lamp (an instrument that enables a doctor to examine the eye under high magnification). Samples of infected secretions may be sent to a laboratory to identify the infecting organism by a culture.
Prognosis and Treatment
Most people with infectious conjunctivitis eventually get better without treatment. However, some infections, particularly those caused by some bacteria, may last a long time if not treated.
If discharge accumulates on the eyelid, people should gently wash the eyelid (with the eye closed) with tap water and a clean washcloth. Warm or cool compresses sometimes soothe the feeling of irritation. Because infectious (bacterial or viral) conjunctivitis is highly contagious, people should wash their hands before and after cleaning the eye or applying drugs. Also, a person should be careful not to touch the infected eye and then touch the other eye.
Antibiotics are helpful only in bacterial conjunctivitis. However, because it is difficult to distinguish between bacterial and viral infections, doctors sometimes prescribe antibiotics for everyone with conjunctivitis. Antibiotic eye drops or ointments, which are effective against many types of bacteria, are used for 7 to 10 days. Drops are usually effective, but ointments are sometimes used because they last longer. However, ointments can blur vision.
Source:http://www.merckmanuals.com/home/eye_disorders/conjunctival_and_scleral_disorders/infectious_conjunctivitis.html?qt=infectious%20conjunctivitis&alt=sh