What are Allergic Disorders of the Eye?
The eyes are the most complex sensory organ in our bodies. Allergies are a common disorder that affects the eyes. You may have eye allergies if your eyes itch, appear red, are tearing up or you feel burning. Eye allergies often affect the conjunctiva, the clear thin, membrane that covers the inside of your eyelids and the white part of your eye (sclera).
An eye allergy occurs when something you are allergic to comes into contact with your eyes. Any substance that causes an allergy is called an allergen.
The most common allergens are pollen, dust mites and animal dander. The conjunctiva contains mast cells that release chemical mediators such as histamine in response to allergens. When airborne allergens contact the conjunctiva of the eyes, they bind to the IgE antibodies on the surface of mast cells which release mediators that are responsible for causing an allergic reaction. This, in turn, causes blood vessels in the eyes to swell, and the eyes to become red, inflamed and very itchy.
Allergic conjunctivitis is one of the most common allergic eye diseases.
- Allergic conjunctivitis is inflammation of the conjunctiva.
- Symptoms include watery, itchy, red, swollen eyes, and dark circles under the eyes (allergic shiners).
- Allergic conjunctivitis can occur alone but often accompanies nasal allergy symptoms.
- Seasonal allergic conjunctivitis occurs only at certain times of the year, usually in spring.
- Perennial allergic conjunctivitis occurs throughout the year and is caused mostly by exposure to dust mites, animal dander, or other allergens present in the home or workplace environment.
Diagnosis of Allergic Disorders of the Eye
- Your allergist diagnoses eye allergies from your complaints (symptoms), eye examination and discussing your medical history, including any family history of allergy.
- A skin test may be helpful to identify the substances that you are most allergic to.
- Your eyes are examined using a special microscope called a slit lamp to check for swollen blood vessels on the surface of the eye which is indicative of an allergic reaction.
- In most severe cases, gentle scraping of the conjunctiva is performed to check for eosinophils (specific type of white blood cells that are commonly associated with allergies).
Treatment for Allergic Disorders of the Eye
- The key to treating eye allergies is to evaluate and control the allergens.
- Some people may have temporary relief from cold compresses on the eyes, however, medications such as oral antihistamines and eye drops may be necessary to treat the symptoms.
- Topical antihistamines, decongestants, mast-cell stabilizers, and the use of oral steroids may help control the itching.
- Immunotherapy or allergy shots may be an option for relieving eye allergies if your symptoms are not controlled by avoiding allergens, using eye drops or medications.