Conjunctivitis is an inflammation (swelling and irritation) of the conjunctiva, the thin layer of tissue covering the eyeball and the inner surfaces of the eyelids. This causes the blood vessels on the eye to swell, making the eye look bloodshot red and feel gritty.
Conjunctivitis can be caused by an irritant, such as chlorine or dust, an allergy (for example, to pollen), or an infection by microbes (bacterias, viruses, chalamydiae etc.). It can also be due to other more rare conditions.
Allergic conjunctivitis will usually affect both eyes and is itchy, while infectious conjunctivitis tends to affect one eye first (which becomes watery), with redness developing in the second eye a few days later.
Some cases of infectious conjunctivitis occur along with a common cold. Infectious conjunctivitis will usually cause a sticky discharge from the eye and crusting around the eyelids and the eyelashes.
If not adequately treated conjunctivitis may become chronic or be associated with long term complications such as chronic tearing.
Treatment will depend on which type of conjunctivitis you have. That is why it is advisable that you consult your Eye Doctor for any red eye longing more than 48 hours.
A painful red eye, especially if assocIated with reduced vision, sensitivity to light, severe headache and feeling sick (nausea) should prompt an emergency appointment.
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