Allergic (vernal or atopic) conjunctivitis is an allergy reaction involving the surface of the eye.
If a pollen, dust or other substance to which a person is allergic lands on the eye, an allergy reaction will occur. Allergic conjunctivitis is often associated with hay fever and often only occurs at certain times of the year.
The symptoms include redness, itching, blurred vision and watering of the eye. In severe cases the white of the eye may swell dramatically and balloon out between the eyelids. There may be a clear, stringy discharge from the eyes, as well as excessive tears, and if the lower eyelid is turned down it appears to be covered with a large number of tiny red bumps. Rarely, ulceration of the eye surface may occur.
It can be prevented by the regular use of sodium cromoglycate drops throughout the allergy time of year. Attacks can be treated by antihistamine tablets and eye drops such as levocabastine and olopatadine. Simple eye drops available over the counter from chemists and containing artery-constricting (vasoconstrictor) medications can be used in milder cases.
Appropriate treatment usually settles the symptoms rapidly.