Hay fever eyes
Seasonal allergic conjunctivitis is the eye equivalent of hay fever and affects up to 25 per cent of the general population. The eyes become itchy, watery and red in the summer pollen season, usually from exposure to grass and tree pollen.
Vernal conjunctivitis is a more severe form of this disease seen in children. The eyes are sticky with a stringy discharge, and it's painful, especially when opening the eyes on waking.
The inner membranes of the eyelid swell and the conjunctiva develops a cobblestone appearance. Corneal damage may occur if the condition is left untreated.
Perennial allergic conjunctivitis tends to occur all year round, with house dust mite and cat allergies. The symptoms are usually milder than those in seasonal allergic conjunctivitis.
Eczema eyes
Although rare, atopic keratoconjunctivitis is the most severe manifestation of allergic eye disease. It occurs predominantly in adult males and is the eye equivalent of severe eczema.
This persistent condition results in constant itching, dry eyes and blurred vision. It's associated with corneal swelling and scarring. Eyelid eczema and infection are common, and lens cataracts may develop over time.
Contact lens allergy
Contact lens wearers may develop giant papillary conjunctivitis, triggered by constant local irritation by the contact lenses on the conjunctival surfaces. The lining of the upper eyelid is usually most affected. Disposable contact lenses may help settle symptoms, but occasionally wearing contact lens has to be suspended.
Never use steroid eye drops unless under the direct supervision of a doctor. Although they're effective for treating eye allergies, they can lead to unwanted side-effects such as glaucoma and cataract formation.
They may also encourage infections of the eye, with resultant corneal scarring.
Eye allergy treatments
Regular use of anti-allergy eye drops such as sodium chromoglycate, nedocromil, olopatidine and lodoxamide can help to treat mild seasonal disease.
Non-sedating oral antihistamines - cetirizine, loratadine, mizolastine and fexofenadine - can also help, especially when there's an associated nasal allergy.
Corticosteroid eye drops occasionally have to be used for more severe eye allergies, but this should be for short periods only.
