by Michael Cole, OD, Child and Family Eye Care Center
A QUESTION OFTEN asked by patients in our clinic is, “Why are my eyes always red?” There could be many reasons for red and irritated eyes, but the most common cause is definitely dry eyes. Dry eye syndrome is inflammatory in nature. The drier one’s eyes are, the more inflamed they become. With increased inflammation, tear production is decreased, creating a hard- to break cycle of redness and irritation.
Dry eye symptoms can vary widely. Often patients will complain of eyes that burn, sting, itch, or feel like something is in them. The eyes will often water excessively when they are dry, which may seem counterintuitive. Increased tear production is, however, the body’s only response to combat dry eyes. When the brain receives a distress signal that the eyes are irritated, it reacts by opening up the floodgates and sends more water to put out the fire. When these poor quality watery tears are unable to drain from the eye fast enough, we often find them running down our cheeks.
The tears on the surface of our eyes are absolutely essential. In fact, if we did not have tears, our eyes would cease to function normally, and the ocular surface would become skinlike and opaque, (definitely DON’T Google keratinization of the cornea). Tears serve several functions such as keeping the ocular surface hydrated, protecting from infection, flushing out foreign bodies in the eye, and aiding in the expression of emotion.
The tear film is not made of only water, but is also composed of lipids (oils), mucin, enzymes, and more. The lipids in the tear layer are especially important, because they prevent the tears from evaporating into the air around us too quickly. The lipids are secreted onto the surface of the eye by what are called meibomian glands, which are inside of the eyelids. The most common forms of dry eye occur when the meibomian glands are not functioning properly, leading to inefficient, evaporative tears. Many of the treatments for dry eye attempt to reduce inflammation and increase function of these oil-producing glands.
Lack of moisture on the ocular surface can also cause vision to be blurry and/or fluctuate throughout the day. When the cells on the surface of the cornea are not properly hydrated, they die and start to fall away from the epithelium. This is not unlike the phenomenon of dry skin. When skin gets dry, it gets flaky and uncomfortable. When this occurs on the surface of the eye, it creates a poor optical surface for light to pass through and causes blurry vision, much like scratched up lenses in a pair of glasses. This blurriness will often improve after several blinks, only to get hazy again after the eyes are left open. Glasses or contact lenses cannot fully correct one’s vision that is impaired due to dryness.
The environment that we are in can impact dry eyes greatly. In humid climates, the moisture in the air aids hydration. In our arid mountain climate, low humidity can exacerbate the problem. Heaters and air conditioners can further reduce humidity, making climate-controlled buildings especially uncomfortable for dry eye sufferers.
Contact lens wearers may also experience an increase in dryness symptoms while wearing their lenses. Soft contact lenses are like sponges, soaking up the moisture from the surface of the eye. Due to the nature of reusable lenses, those wearing monthly disposable lenses will likely experience more symptoms than those prescribed daily disposable lenses. Those who overwear their contact lenses will experience the most discomfort and redness.
There are many ways to combat dry eye. First, supplement lubrication with artificial tears. There are many over-the-counter eye drops that are safe to use. The only drops to avoid are those that advertise “redness” relief. Often these types of drops have unwanted added ingredients that will actually make the problem worse rather than improve the situation. Eye drops that state “lubricant” or “tears” on the bottle are generally safe to use. You can check the ingredient lists to avoid unwanted additives. These lubricant drops need to be used several times a day in order to improve symptoms of dry eye.
Other treatment methods may include improving one’s environment in ways such as adding humidifiers to the home or office. Warm compresses on the eyelids can help the expression of meibomian glands. Often, we sleep with our eyes partially open, and the use of ophthalmic gels, ointments, and sleep masks can help protect the eyes from drying out while sleeping.
Because dry eye is so common, many treatment methods have been developed. Other than the suggestions here, we invite those struggling with dry eye to contact our office for further relief.