Dry eye is a condition in which a person doesn’t have enough quality tears to lubricate and nourish the eye. Tears are necessary for maintaining the health of the front surface of the eye and for providing clear vision. Dry eye is a common and often chronic problem, particularly in older adults.
With each blink of the eyelids, tears spread across the front surface of the eye, known as the cornea. Tears provide lubrication, reduce the risk of eye infection, wash away foreign matter in the eye and keep the surface of the eyes smooth and clear. Excess tears in the eyes flow into small drainage ducts in the inner corners of the eyelids, which drain into the back of the nose. Dry eyes can occur when tear production and drainage is not in balance.
This disease can come from a number of causes, including physical and environmental. One common cause is when tear glands slow down tear production-a normal occurrence that happens with age, especially in women going through menopause. Tear quality may also be the cause of dry eyes. In a normal tear, there are three components-water, mucous, and oil. These three components work together to provide the proper amount of moisture, distribute moisture evenly across the ocular surface, and prevent evaporation that can cause eyes to become dry. If any of the three components is compromised, the eye may not get the nourishment and protection it needs. Most commonly, there is not enough oil in the tears, leading to the evaporation that causes dry eye. Diminished tear production may be associated with certain medications, such as antihistamines, birth control pills, diuretics, high blood pressure medicines, heart medicines, pain relievers, and anti-inflammatories, and certain medical conditions, such as diabetes, rheumatoid arthritis, or thyroid problems.
An adequate and consistent layer of tears on the surface of the eye is essential to keep your eyes healthy, comfortable and seeing well. Tears bathe the eye’s surface to keep it moist and wash away dust, debris and microorganisms that could damage the cornea and lead to an eye infection. Each component of the tear film serves a critical purpose. For example, tear lipids help keep the tear film from evaporating too quickly and increase lubrication, while mucin helps anchor and spread the tears across the surface of the eye. A problem with any of these sources of tear film components can result in tear instability and dry eyes, and there are different categories of dry eyes, depending on which component is affected.
A variety of approaches can be taken to treatment. These can be summarized as: avoidance of exacerbating factors, tear stimulation and supplementation, increasing tear retention, and eyelid cleansing and treatment of eye inflammation. Dry eyes can be exacerbated by smoky environments, dust and air conditioning and by our natural tendency to reduce our blink rate when concentrating. Purposefully blinking, especially during computer use and resting tired eyes are basic steps that can be taken to minimize discomfort. Rubbing one’s eyes can irritate them further, so should be avoided. Conditions such as blepharitis can often co-exist and paying particular attention to cleaning the eyelids morning and night with mild soaps and warm compresses can improve both conditions.