Allergy of the eyes is basically similar to allergies of other parts of the body like skin (eg eczema) or lung (eg asthma). The bodies' immune system mistakes substances in the environment called allergens (eg pollen) for harmful micro-organisms and attacks them. The symptoms depend on where the allergen is located, for example allergy in the lungs causes wheezing whereas in the skin there is a rash.

Many substances can cause eye allergy. These include pollen, animal fur, house dust mite, cosmetics, contact lenses and the solutions used to clean them and eye drops used to treat eye disorders. In fact the preservatives in eye drops are a common cause of eye allergy. Often the cause of the allergy is a mystery and unfortunately allergy skin tests to not work for eye allergy.

The symptoms are eye redness, irritation, weeping and sometimes swelling of the white part of the eye or the eyelids. The symptoms may only occur at certain times of the year, for example summertime in pollen allergy, or may be year round.

The diagnosis is made from the symptoms and examination findings. I check for evidence of allergy on the inner lining of the upper and lower eyelids. Allergy causes numerous minute swellings of the lining called papillae and follicles.

The treatment is firstly to avoid the allergen if possible, for example it may be obvious that the problem is due to contact lens wear in which case switching to glasses is curative. Frequently this is not possible in which case it is necessary to use eye drops to suppress the symptoms. I usually prescribe Rapitil, Livostin or Emadine all of which are effective. Sometimes it is appropriate to take a short course of weak steroid eye drops such as Predsol until the symptoms settle.

Most allergies are relatively mild and easy to treat. However some rare allergy syndromes are more severe and require different treatment, for example vernal keratoconjunctivitis and atopic keratoconjunctivitis.