Blinking is like breathing. You do both without thinking thousands of times each day.
As long as everything is going well, you won’t even notice when you blink. You also won’t be aware if you forget to blink. When you watch a video on your smartphone or get caught up in correspondence on your computer, you may be so focused that you fail to blink frequently enough.
That may not seem like a big deal, but blinking is critical for spreading tears over the surface of the eye and keeping it moist, clean and well-nourished. Infrequent or incomplete blinking may be contributing to an apparent epidemic of dry eye. A Wall Street Journal article (July 9, 2013) notes that as many as 25 million Americans suffer from this malady.
Optometrists and ophthalmologists are diagnosing this condition in increasing numbers of patients, who describe a persistent sensation of grit or sand in the eye. Sometimes dry eye feels like burning that becomes more intense as the day wears on. Severe dryness can damage the cornea, creating a vicious cycle of pain and dysfunction.
Dozens of medications can contribute to dry eyes. Antihistamines such as cetirizine (Zyrtec), loratadine (Claritin) and diphenhydramine (Benadryl) can do it. So can drugs for overactive bladder like fesoterodine (Toviaz), oxybutynin (Ditropan) and tolterodine (Detrol). Antidepressants such as amitriptyline, citalopram, doxepin, fluoxetine and sertraline also may trigger dry-eye discomfort for some people. For a more comprehensive list, visit www.PeoplesPharmacy.com.
Dry eyes have traditionally been treated with eye drops to substitute for natural-tear film. Picking artificial tears, however, can be challenging. Some experts caution against products with preservatives, though they lengthen shelf life. Others suggest products such as Soothe XP that can protect the surface of the eye and replenish the tear film lipid layer.
During the past several years, research has shown that tears are more than just salty water. In addition to the aqueous (watery) part of tears, the eyelids have glands that secrete a thin film of oil. Every blink brings the top and bottom lids together, and they squeeze each other gently. This helps the glands release oil that floats atop the watery portion and keeps it from evaporating too quickly.
If you don’t blink often or hard enough, the oil will stay in the glands, thicken and eventually plug the opening. While eye drops can replenish the liquid, eye doctors have been challenged to help patients restore the natural oil.
Now a company has developed a device that does just that. The LipiFlow machine warms and presses the eyelids to unclog the glands and get the oil flowing again. One study compared LipiFlow to warm compresses (the usual recommendation) and found the device was significantly better (Cornea, April 2012). For most people, one treatment can ease dry-eye symptoms for up to a year (Clinical and Experimental Ophthalmology online, Dec. 14, 2012).
Our ancestors probably suffered dry-eye symptoms much less often than we do. Air conditioning that lowers humidity, computers and many medications all contribute to the current dry-eye epidemic.
Since we are not likely to give up our dependence on these modern conveniences, we will need more reminders to blink consciously and completely.