LASIK & Dry Eyes
Reviewed by Leslie Doctor, M.D.
Dry Eyes can occur both before and after LASIK Eye Surgery. Dry Eyes may be exacerbated in patients who had the condition prior to their surgery. Dry Eyes can actually be caused temporarily by having LASIK. It is important when considering LASIK, that you understand the basics of Dry Eye Syndrome so that you can alert the LASIK surgeon to the possibility that you may be predisposed to Dry Eyes. You may to take a short dry eyes quiz to learn more. That way proper preoperative treatment can be provided to you so that you will have the best possible LASIK results and experience.
What is Dry Eye Syndrome?
The eye requires that it be continuously covered by natural tears produced by the eye. Dry Eyes is a condition where some people so not produce enough tears to keep the eye comfortable and healthy. This condition where not enough tears are produced is called Dry Eyes. Tears may be produced by two different methods in the eye. In the first method, tears are produced at a slow and steady rate and provides the eye with its natural lubrication. In the second method, your eyes produce large quantities of tears in response to irritation or strong emotions. If your eyes are healthy they constantly produce enough lubricating tears. If your eyes are irritated by getting something in them such as a foreign body, crying...or if they are too dry, they will produce an excessive amount of tears.
What Are The Symptoms of Dry Eyes?
If you have Dry Eyes you may experience a number of common symptoms that can include stinging or burning, scratchiness, excessive mucous in or around your eyes, reduced tolerance to smoke or wind, difficulty wearing contact lenses and possibly excessive tearing. Excessive tearing from Dry Eyes sounds completely illogical. However, if the normal tears are not produced in a sufficient amount to keep your eyes lubricated and wet enough, your eyes will become irritated and will water excessively. This occurs because the Lacrimal Gland begins to produce a large amount of tears to compensate for the irritation and this overwhelms the eye's drainage system.
What is The Tear Film?
A normal tear film consists of three layers. The outermost layer of the tear film is called the Oily Layer and is produced by the Meibomian Glands. This layer produces a smooth tear film and prevents it from evaporating too quickly. The middle layer is called the Aqueous layer is the watery layer that washes away debris from the eye's surface. It is produced by the Lacrimal Gland and is what we normally think of as tears. The innermost layer is called the Mucous Layer and is composed of mucous produced by the conjunctiva or the clear covering of the eye tissues. The Mucous Layer allows the normal tear film to stick to the surface of the eye. Your eyelids act to smooth the tear film and smooth it over the eye's surface each time you blink. This produces a smooth optical surface and clear vision. People who have Dry Eyes and do not have a smooth and regular tear film often have blurry vision from the lack of a smooth tear film.
What Causes Dry Eye?
As we age the normal production of tears begins to slow down. Even though Dry Eyes can occur in men and women, Dry Eyes most commonly occurs in women approaching and after menopause. Dry Eye can be caused by some systemic diseases such as Sjogen's Syndrome in which the Dry Eyes may be accompanied by a dry mouth and arthritis all at once. There are many common over the counter as well as prescription medications that can reduce the production of tears and cause Dry Eyes. It is important that you tell your doctor all of the medications that you are taking so he or she can be certain they are not the cause of the Dry Eyes. In particular if you are taking diuretics for blood pressure, beta blockers for heart conditions or blood pressure, antihistamines for allergies or colds, sleeping pills, any medications for nerves or pain relievers please tell your eye care provider. Since these medications are necessary for your health it may be necessary to use artificial tears to alleviate the Dry Eyes symptoms. You should consult your eye care provider because the selection of the right artificial tear is important. Many artificial tears contain preservatives that can actually make the Dry Eye symptoms worse for some patients. Your eye care provider may recommend a special preservative free artificial tear for better results.
How is Dry Eye Diagnosed?
There are several diagnostic tests that your eye care provider may use to help diagnose Dry Eyes. The first test is called a Schirmer Tear Test and involves placing a small strip of filter paper under the lower eyelid. This test measure the actual rate tear film production. A second test is called a Break Up Time and involves placing a small amount of fluorescent dye in your tears and observing the patterns of dryness of the tear film on the eye's surface. The third test is called a Lactoferrin Assay which can measure the amount of Lactoferrin in your tears indicating whether a Dry Eye is present.
How is Dry Eye Treated?
There are many ways to treat Dry Eyes beside simply artificial tears depending on your particular situation. These include easily placed Tear Duct Plugs to help you retain a greater amount of tears that you produce, certain dietary supplements as well as prescription medications such as Restasis which will actually stimulate your own natural tear film production. You should have a thorough diagnostic evaluation with your eye care provider and they will help decide if you have dry eyes and which treatment options will be best for you.
Why Does LASIK Cause Dry Eyes?
LASIK may cause some patients to experience Dry Eyes after their surgery. This is especially true if there was tendency toward dry Eyes before the LASIK procedure. During the LASIK procedure, a thin layer of tissue is created, called a flap, under which the actual laser energy is applied to reshape the cornea to correct nearsightedness, farsightedness and astigmatism. Anatomically, when the flap is created, the very fine cornea nerves may be severed as part of the LASIK procedure. This is a normal part of the procedure. However, these nerves are required in order "signal" the Lacrimal Gland to produce tears. So, sometimes, the temporary interruption of the corneal nerve impulses can actually cause a lesser amount of tears to be produced, resulting in Dry Eyes after LASIK. Sometimes if the Dry Eyes after LASIK are moderate or severe, your vision may actually be blurry due to the tear film instability. Your LASIK surgeon may elect to treat you for Dry Eyes before your LASIK procedure in order to fortify your tear film so that you will have a comfortable and asymptomatic post operative period. ALL LASIK patients will need to use artificial tears or lubricating drops as a matter of course as it helps the tear film reestablish itself after the LASIK procedure. During your consultation it is important to disclose any symptoms you may have of Dry Eyes and to disclose any medications you are taking that might predispose you to dry eyes after your LASIK procedure. In this way, your LASIK surgeon can take the necessary steps to prescribe whatever is necessary to obtain the best possible results for you. Fortunately, virtually all Dry Eyes symptoms after LASIK are temporary and gradually decrease over time until they end within a few months of having your LASIK procedure.