Tearing eyes are very common, affecting 12 million Americans. Tearing can be caused by too much tear production, too little of the right kind of tears to keep the eye moist, or a problem with tear drainage. Irritants to the eye cause excessive reflex tearing. Strong emotions also cause tearing. Although they may be annoying at time, tears are part of the eye's system for protecting itself from further damage.
Dry Eye Syndrome
Ironically, one of the main causes of tearing is dry eye syndrome. The eyes don't make enough of the type of tears that stay on the eyeball to provide lubrication, so the eye produces an abundance of reflex tears to compensate. Lubricating tears that stay on the eye longer or plugs that block the leaking tear ducts and keep tears on the eye longer are used to treat dry eye syndrome.
Allergies and Irritants
Allergies are common causes of tearing eyes, as the eye overproduces tears to wash out the irritants. Allergic reactions that affect the eye include hay fever, seasonal allergies and atopic dermatitis. Contact lenses can also cause an allergic reaction. Irritants such as smoke, wind, dust or other particles in the eye cause reflex tearing, which helps wash out the irritants. Antihistamines can help decrease symptoms in hay fever and seasonal allergies. Restricting wear time and changing cleaning solutions may help reduce tearing in contact lens allergies, the University of Michigan Kellogg Eye Center suggests.
Conjunctivitis
Conjunctivitis is caused by a viral or bacterial infection, allergies or irritation of the tissue layer that covers the lower eyelid and the lower part of the eye, the conjunctiva. Conjunctivitis, also called pink eye, causes reflex tearing and often copious purulent discharge; the eye turns red and feels gritty, itchy and irritated, the Mayo Clinic states. Viral conjunctivitis and allergies are most likely to cause a watery discharge.
Corneal Abrasion
Corneal abrasion results from trauma to the cornea, the dome-shaped tissue that covers the iris, the colored part of the eye, and the pupil. A scratch or injury to the cornea produces extreme pain, reflex tearing, light sensitivity and redness. Corneal abrasions usually heal quickly; antibiotics, lubricating ointments and patching the eye may help it heal, the University of Illinois at Urbana-Champaign reports.
Blepharitis
Blepharitis is an inflammation of the eyelids that causes a scaly, flaky dandruff. Symptoms are reflex tearing, redness and swelling of the lids, dry eyes, crusting on the lids, grittiness and itching. Tearing associated with blepharitis may be caused by irritation from inflammation or by irritation from eyelashes turning in against the eye.
Dacryocystitis
Dacryocystitis is an infection of the lacrimal sac, which drains tears from the eye. When the lacrimal sac becomes infected, tears can't drain properly through the drainage canals of the eye, so the eye becomes watery, red, painful and swollen. Antibiotics are needed to clear up the infection.
