Direct contact with certain substances can irritate the eye and cause inflammation.
The conjunctiva and the white of the eye redden, and the fine vessels of the eyeball appear enlarged. The eye may water excessively and cause the animal discomfort and itching. If contact was limited and for a short period of time, symptoms may disappear spontaneously within 1-2 days. If the irritating substance is present over a longer period of time, inflammation will be prolonged, and symptoms may become more intense.
Contact allergy is caused by physical contact with an allergen. Common allergens are pollen or plant material found during spring and summer. Other possible sources of irritation are newly laid carpets, paints, varnishes, and dust mites.
Symptoms and medical history are usually sufficient to diagnose allergy related distress. However, the eye has to be thoroughly examined in order to assure that there is no other source of irritation or foreign body present. Therapy is aimed at removing the underlying cause. If that is not possible, medication such as anti-inflammatory eyedrops and medication have to be given during sensitive periods.
If you suspect that the allergy is being caused by plants or pollen in your garden, or somewhere else outside the house, the animal should be kept inside for the next 48 hours. Consult a veterinarian if symptoms do not disappear by themselves. If an irritant has sprayed or leaked into the animal's eye, you can wash the eye with lukewarm water, which should be mixed with a bit of salt.