Dry eye occurs when the eye does not produce adequate tears, or when the tears are not the proper consistency, and evaporate too quickly.

What are tears made up of, and how do they relate to dry eye?

Tears are produced by the lacrimal gland and are necessary for eye health and vision. Tears bathe the surface of the eye keeping it moist and remove dust and debris, keeping it healthy and help prevent infections from bacteria and other microbes.

Tears are a combination of water, an outer oily layer that helps prevent evaporation, and an inner layer of mucus to adhere the tears to the cornea. Tears also contain proteins, electrolytes, vitamins, and have enzymes that help kill germs.

Tears are produced constantly, and bathe, nourish, and protect the eye. An increase production of tears is frequently a result of irritants such as dust, dirt, chemicals, and other debris, an infection or irritation, or strong emotions. An increase in tearing may also be a response of dry spots that form in the wind, air conditioning and heating circulating across the eye surface, causing reflex tearing. Thus an eye that tears intermittently may be a paradoxical response to dry eye.

What are the symptoms of dry eye?

Dry eye symptoms may include the following:

• Burning and stinging of the eyes
• Sandy or gritty eyes, like something is in the eye
• Redness and pain in the eyes
• ­Excess tearing, followed by dryness
• Episodes of blurred vision that sometimes clears with blinking
• Reduced tolerance to reading , computer use, or near visual tasks
• Eye fatigue

What causes dry eye?

There are several causes of dry eye:

• Side effects of some medications, such as decongestants, antihistamines, some blood pressure medications, oral contraceptives, and antidepressants
• Diseases of the eyelids, such as blepharitis and meibomian gland dysfunction
• Allergies can result in dry eye
• Infrequent blinking, especially during reading or staring at a computer screen
• Inadequate vitamins, especially vitamin A
• Autoimmune disorders, such as rheumatoid arthritis, lupus, and Sjogren’s syndrome, causing inflammation of the ocular surface and dry eye
• Increased surface area exposure of the eye, seen in thyroid eye disease, or after lid surgeries, such as blepharoplasty
• Contact lens wear and sometimes after LASIK surgery

How is dry eye treated?

Depending on the condition, cause, and severity of dry eye, your eye care professional may use various treatment and approaches. The first approach is to try to determine the cause of dry eye. Dry eye is most commonly a chronic condition, thus no “cure” is available, only control. If an underlying disease or disorder is found, such as blepharitis or meibonian gland dysfunction, it first needs to be treated or controlled.

Artificial tears, gels, and ointments are the first line of therapy.  Restasis (cyclosporine A), an anti-inflammatory eye drop, is the only prescription drug to treat dry eye. It does not help all dry eye conditions, but is especially effective for inflammatory causes of dry eye, such as seen in autoimmune diseases and allergic dry eye.

If contact lenses are causing dry eye, your eye care practitioner may change to a moister contact lens or a newer material that helps in dry eye conditions caused by contact lens wear.

Another option is plugging the drainage holes of the eyelids using punctual plugs, thus retaining more tears on the eye surface, can be useful in more advanced cases.

In some cases, increased intake of omega fatty acids from cold water fish, such as salmon and tuna, or omega 3 dietary supplements (especially with DHA and EPA) may help dry eye symptoms. Omega 3 fatty acids may help reduce inflammation which can cause dry eye.

If you have dry eye, discuss your symptoms and treatment plans with your eye care professional. Dry eye generally worsens with age, so get treatment early. In some cases of dry eye (especially inflammatory dry eye conditions), proper treatment can prevent permanent damage to the tear-producing glands of the eye, and reduce the symptoms of dry eye.

Dennis O’Neal is a doctor of optometry at Washington Eye Center.