Well, in case you haven’t noticed, the weather is cooling off quickly. (I’ve lived in the Midwest all my life and it sneaks up on me every year!) The fall colors are beautiful, and the smell of pumpkin spice is in the air. It also means it’s time to get out your coat, your mittens, your boots… and your eye drops! That’s right—when the humidity in the air drops, dry eye symptoms can get worse. So, I thought now would be an appropriate time to talk about dry eye.
What causes dry eye?
Dry eye is caused by not enough moisture on the eye’s surface. Seems simple enough, but there’s a little more to it. The tear film on the surface of the eye is made up of three components. The water, or aqueous, component is the most obvious, and is made by the lacrimal glands on the inside of the eyelids. There is also an outer oily layer that is made by the meibomian glands that empty just behind the eyelashes; the oil keeps the tears from evaporating too quickly. The inner mucous layer, which is made by the conjunctiva (a sheet of thin tissue that covers the white part of the eye and lines the inner surface of the eyelids), helps the tears stick to the surface of the eye. So, dry eye can be caused by not making enough of the aqueous component OR by not secreting enough of the oily component which allows the tears to evaporate too quickly OR by having too little of the mucous component, so the tears don’t stay on the eye’s surface… or most commonly, by some combination of the above.
How do I know if I have dry eye?
Dry eye can happen to anyone at any age, but it is more common the more birthdays someone has (i.e. the older we get), and it is more common in women than in men. Also, some conditions (like autoimmune diseases) are associated with dry eye and some medications (like blood pressure medications) can cause or worsen dry eye. Finally, some behaviors like prolonged reading or screen time, being in windy, dusty, or smoky environments, or wearing contact lenses can cause dry eye.
The most common complaint in dry eye patients is not always that the eyes “feel dry.” Patients with dry eye often describe a stinging, burning, scratchy, or gritty feeling in the eye; sometimes it even feels like there is something in the eye(s). Other complaints are blurred vision (usually with much fluctuation throughout the day and changes with blinking), stringy mucoid discharge, redness, and TEARING! Yes, you heard me right. Frequently, when the eye is very dry and irritated, the body makes tears to try to soothe it, but without the right balance of oil and mucous mixed in, the aqueous portion alone is not thick enough or sticky enough to remain on the surface of the eye and ends up running down the cheek.
How is dry eye treated?
Once you’ve been diagnosed with dry eye, the first line of treatment is lubricating eye drops. These so called “artificial tears” are designed to closely approximate your own tears with a balance of water, oil, and mucous. These are available over the counter without a prescription and can be used as often as necessary. Which brand you use is based on personal preference, but keep in mind that some drops have a preservative known as Benzalkonium Chloride (BAK) which is very irritating to some people. If you are using artificial tears more often that 3-4 times per day or if you have sensitive eyes, consider using a preservative free formulation of drops. There are thicker preparations—like gel drops, gels, and ointments—that are useful for more severe cases of dry eye or can be used at bedtime to help restore the health of the ocular surface overnight.
Something that is also very important to your tear film is maintaining the health of your meibomian glands, the oil glands in the eyelids. As previously mentioned, the oil is what keeps the tears from evaporating too quickly. Each time you blink, a small amount of clear oil should be expressed from these glands onto the surface of the eye. Lid hygiene should be performed regularly, from a few times a daily to a few times a week, based on your doctor’s recommendation. Start with a warm compress applied to the eyelids for 3-5 minutes; this “melts” the oil in the glands. Then, blink forcefully 15-20 times or massage the eyelid margins; this promotes movement of the oil out of the glands. Finally, cleanse the eyelids around the base of the lashes with gentle soap, commercial eyelid cleansers, or baby shampoo.
Another option is to block the tear duct openings that normally drain the tears from the eyes using small plugs. This keeps the tears that the body makes in the eyes longer. There are also prescription eyedrops that can increase the eye’s natural tear production.
Finally, some lifestyle changes can make a big difference in keeping the eyes moisturized. When doing visually demanding tasks like reading or using a computer, take frequent breaks, e.g. set a timer for 10 minutes and when it goes off take a 1-minute break to close your eyes or look off into the distance. Also, use a humidifier in the room where you spend the most time, like next to the computer or the armchair where you read. Wear wrap around sunglasses or “onion goggles” to hold the moisture in, especially when you plan to be outside or in the wind. Talk to your primary care physician about taking an omega 3 supplement which can help with meibomian gland health and thus ocular surface health.