When your body's immune system becomes sensitive and overreacts to something you begin to develop allergies. Allergic reactions can occur when the allergen comes in contact with antibodies in the mast cells of your eyes. At the point of contact, your cells release histamine, other substances and chemicals that cause tiny blood vessels to leak, when this happens your eyes become itchy, red, and watery.
There are 5 primary types of eye allergies:
1. Seasonal and perennial allergic conjunctivitis (SAC/PAC): The most common form of eye allergy. Those who suffer from SAC/PAC typically experience it in the Spring, Summer, and/or Fall. Symptoms of SAC/PAC are generally brought on by different types of pollen. Symptoms include: Itchy, red, burning, and/or watery eyes.
2. Vernal Keratoconjunctivitis: This eye allergy is more serious than SAC/PAC. It can occur in every season, but symptoms can worsen depending on the season. Generally, boys and young men suffer from vernal keratoconjunctivitis and 75 percent of those who deal with vernal keratoconjunctivitis also have asthma or eczema. Symptoms include: itchy eyes, watery eyes, foreign body sensation of the eye, and light sensitivity. If untreated, vision can be impaired.
3. Atopic Keratoconjunctivitis: This type of eye allergy for the most part affects older patients. In particular, it affects men with a history of allergic dermatitis. Symptoms of Atopic keratoconjunctivitis are similar to vernal keratoconjunctivitis and can go all year-round. Symptoms include: severe itchy eye, burning eyes, red eyes, lots of mucus production around the eye after sleep—may cause eyelids to stick together.
4. Contact Allergic Conjunctivitis: This occurs when the eye is irritated by contact lenses or rather, the proteins from your tears that bind to the surface of the lens. Symptoms include: Red eyes, itchy eyes, mucous discharge, and lens discomfort.
Giant Papillary Conjunctivitis: Like Contact Allergic Conjunctivitis, Giant Papillary Conjunctivitis is associated with wearing contact lenses, however, it is much more severe. Symptoms include: Itchy eyes, puffy eyes, teary eyes, blurring vision foreign body sensation, lens discomfort, and mucous discharge.