It is estimated that about 75% of allergies are associated with eye diseases, which are mostly hereditary. These allergies are mainly caused by pollen, mold, dust, pet dander, foods, bee stings and even certain eye drops. Most of them are airborne. If you are allergic to eye drops, they are most likely to contain preservative.

Most of the allergies involve people’s eyes and noses, such as red, swollen, or itchy eyes, and runny, itchy nose. Others include sneezing, coughing, headache, and itchy mouth or throat. More severe conditions may be conjunctivitis and rhinoconjunctivitis. Not all substances that cause allergy are harmful, such as dust. Their harmful effects may come from the people’s overreaction.

The simplest way to "treat" allergies is avoiding the allergens, such as pet dander and pollen. And individuals can wear wraparound sunglasses to get protection. Once you have suffered from allergies, medications such as eye drops can help you alleviate the symptoms. Over-the-counter medications are always cheaper, while prescription medications are more effective. And antihistamines are always effective in treating airborne allergies, such as itchy, watery eyes and so on.

Two types of treatments are available for red eyes. Decongestants can temporarily lessen the apparent redness by reducing the size of blood vessels. But it always causes rebound hyperemia, which means that if decongestants are removed, the patient’s vessels will become larger than their initial sizes. Another redeye treatment is mast cell stabilizer, which can relieve redeye in a longer term. Most allergies cause your eyes to water and your nose to run. The underlying reason is the release of histamine, so that antihistamines are created to cure redeye. Nonsteroidal anti-inflammatory drug and prescription corticosteroid eye drops can be prescribed to decrease swelling, inflammation and conjunctivitis, while some of which may cause certain side effects.

Seasonal allergies may cause discomfort for some contact lenses wearers, since airborne allergens can get on the lenses.

While switching eye drops for contacts cleaning, you should always consult your doctor, since some drops can discolor or damage certain lenses. The most convenient choice is daily disposable contact lenses, which are unlikely to develop irritating deposits and discomfort.