Dry eye is a disease that occurs when the eye does not produce enough tears. It may also occur when the eye makes poor quality tears, such as tears that evaporate quickly. The surface of the eye is protected by a tear film that has three layers: an inner layer that is made of mucus, a watery middle layer and an oily outer layer. Abnormalities in any part of this film can lead to dry eye. Restasis, prescription eyedrops used to treat dry eye, is produced by Allergan Inc.
Causes
Dry eye, or keratoconjunctivitis sicca, is caused by several factors, such as certain medications and medical conditions as well as advanced age. Inflammation in certain parts of the eye can also lead to dry eye. All these factors can lead to dry eye through several mechanisms, including a dysfunction of the glands that produce the middle and outer layer of the tear film that covers the eye.
Indication
According to "Smolin and Thoft's The Cornea: Scientific Foundations and Clinical Practice," the U.S Food and Drug Administration approved Restasis for the treatment of dry eye due to inflammation. This drug is available as an eyedrop and can only be purchased with a doctor's prescription.
How It Works
The tear film has several important functions. It protects and nourishes the surface of the eye and ensures that the eye surface is smooth for proper vision. Normally, when there is decreased production of tears in the eye, the eye surface sends a message to the brain for secretion of more tears. The brain then stimulates the lacrimal glands to produce more tears.
Inflammation of the lacrimal glands leads to low tear production and dry eye. When this happens, sensation in the eye surface drops. Consequently, signals to the brain drop and the lacrimal glands do not receive enough stimulation for normal production of tears. Restasis has anti-inflammatory properties, and it treats dry eye by reducing inflammation and increasing the eye's ability to produce its own tears.
Side Effects
The text "Dry Eye: A Practical Guide to Ocular Surface Disorders and Stem Cell Surgery," by Amar Agarwal, states that the most common side effect of Restasis is a burning sensation that occurs when it is instilled into the eyes. According to "Dry Eye," other side effects include watery eyes, blurred vision, redness, eye pain, itching, stinging, discharge and feeling as if there is something in the eye.
Precautions
Patients who have active eye infections should not use Restasis. Also, this medication should not be used while contact lenses are in the eyes. Instead, contact lenses should be removed before Restasis is used.
References
- U.S Food and Drug Administration: Priority NDA and BLA Approvals in 2002
- Restasis: Learn About Restasis
- "Smolin and Thoft's The Cornea: Scientific Foundations and Clinical Practice"; Gilbert Smolin, Charles Stephen Foster, Dimitri T. Azar, Claes H. Dohlman; 2005
- "Dry Eye: A Practical Guide to Ocular Surface Disorders and Stem Cell Surgery"; Amar Agarwal; 2006
- American Optometric Association: Dry Eye
