Allergic conjunctivitis is divided into several subtypes depending on the nature of the allergen. Seasonal allergic conjunctivitis, vernal conjunctivitis, perennial allergic conjunctivitis, atopic keratoconjunctivitis, medication reactions, contact lens allergy, giant papillary conjunctivitis, contact eye allergies and toxic papillary reactions are some of the most common type of eye allergies.

Seasonal Allergic Conjunctivitis: Seasonal allergic conjunctivitis as the name suggests are eye allergies caused during the particular season of a year. In it the eyes become red, watery and itchy. Persons affected also have burning sensation and eyelid swelling. During the summer season, it is caused due the exposure to grass and different types of tree pollen. In the fall, it is caused mainly due to the exposure to weed pollen. Seasonal allergic conjunctivitis is sometimes referred as ?hay fever eyes or hay fever conjunctivitis or allergic rhinoconjunctivitis.? An estimated 25% of American population is affected by seasonal allergic conjunctivitis.

Topical antihistamine, topical decongestants and mast cell stabilizers are the ideal treatments. An ophthalmologist should be consulted, if there is a decrease in vision or excessive pain or thick discharge,

Vernal Conjunctivitis: Vernal conjunctivitis is a severe form of seasonal allergic conjunctivitis and is mainly seen in children and youngsters. In it the eye become itchy, red and watery and develops pain. The eyes become sticky due to a discharge and are quite hard to open. The pain intensifies when opening the eyes after sleeping. The inner membranes of the eyelids swell and conjunctiva has change in appearance. Vernal conjunctivitis should be treated immediately as it can lead to corneal damage.

Topical antihistamines, mast cell stabilizers, and low dose topical steroids are the most effective form of treatment. The occurrence of the allergy is more common during late spring, when dry and dusty conditions prevail. Using sunglasses can be very helpful.

Perennial Allergic Conjunctivitis: Perennial allergic conjunctivitis occurs throughout the year and can be caused by both indoor and outdoor allergens. The main causes are house dust mites, pet dander and several other indoor allergens. In it the eyes become mildly itchy, watery and red.

Atopic keratoconjunctivitis: Atopic keratoconjunctivitis is one of the most severe forms of eye allergies. People with eczema are more prone to it. Continuous itching and dry eyes are the common symptoms, which is followed by blurred vision. Atopic keratoconjunctivitis, also referred as eczema eyes, if not treated can lead to corneal swelling and conjunctival scarring. This form of eye allergy is quite rare and is seen mainly in older people.

Apart from airborne allergens, atopic keratoconjunctivitis can be caused by common food substances. Topical antihistamines, mast cell stabilizers and short term use of steroids are the ideal treatment. This type of allergy should be treated immediately as there have been rare cases which have led to blindness.

Medication Reactions: Eye allergies can be caused by the intake of certain medicines. Conjunctival swelling and itching are the common reactions. The reactions occur immediately and can vary from mild to severe. Anesthetics, bacitracin, topical penicillin, and sulfacetamide are some of the medicines which can trigger eye allergies.