Your doctor has diagnosed you with dry eye disease. While you work with your eye doctor to treat it, you might wonder what caused your symptoms. Was it something you did or didn't do? Does dry eye run in your family?
Many factors could have put you at risk for dry eye. Some, like your age and sex, aren't under your control. Others, like smoking, screen time, and diet, are within your power to change. Knowing what risk factors could have caused your condition could help your eye doctor choose the dry eye treatment that's most likely to help.
Making the Tear Film
Dry eye disease means your eyes either don't make enough tears or the tears you make aren't good enough to protect and moisten your eyes. This leads to a problem with the tear film that coats your eye.
The tear film consists of three layers:
- An oily layer on the outside
- A watery layer in the middle
- A mucus layer at the bottom closest to your eye
The tear film keeps your eyes moist and protects them from irritation. The meibomian glands in your eyelids produce the oily layer. Lacrimal glands in your upper eyelid make the watery layer. And goblet cells in your eyes mainly produce the mucus layer. A problem with the way your eyes make tears or how well those tears stay on the surface of your eye can lead to dry eye symptoms.
Age
Dry eye becomes especially common as you get older. While around 8% of people under 60 have this condition, it affects 15% of people in their 70s and 20% of those over 80.
Older adults are more likely to get dry eye than young adults because:
- They use more medicines that cause dry eye as a side effect.
- They have loose eyelids that let in air and allow tears to evaporate faster.
- Levels of hormones that affect tears change during menopause.
- They're more likely to get autoimmune diseases.
- They make fewer tears overall.
Sex
Women get dry eye more than men, and they develop it at a younger age. Hormone changes during menopause are one reason for the difference. Shifting levels of the hormones estrogen, progesterone, and androgens reduce the quantity and quality of the tear film.
Another reason why women get dry eye more often is because they're more likely to have autoimmune diseases like rheumatoid arthritis and Sjӧgren's syndrome that cause dry eye. Also, eye makeup can block glands in the eyelids that add oil to the tears.
Screen Time
Sitting in front of a computer screen for hours on end is a risk for dry eye. Every time you blink, tears spread across your eyes to keep them lubricated. Normally, you blink 18 to 22 times a minute. But when you stare at a computer, tablet, or cell phone screen, you blink only 3 to 7 times a minute.
Not blinking enough makes your eyes dry out. Dry eye is one symptom of computer vision syndrome, a group of symptoms like headaches, blurred vision, and neck pain caused by long-term screen use.
Contact Lens Use
About 45 million people in the United States wear contact lenses. While contacts can free you from having to wear glasses, they can also be uncomfortable.
Friction from the lens rubbing against your eye can cause inflammation, damage the tear film, and reduce the normal flow of tears over your eye. The discomfort from dry eye causes many contact lens wearers to switch to glasses.
Family History
Dry eye may run in families. Shared genes are likely the reason. Researchers have discovered many genes related to dry eye that are involved with inflammation, tears, and corneal health. Genetics may set some people up for dry eye, but then environmental factors trigger the condition.
Eyelid Problems
Your eyelids are home to the meibomian glands, which make the oily part of your tears. A few eyelid conditions block these glands or prevent your eyes from closing all the way.
Blepharitis. This is redness and inflammation of your eyelids. Allergies, infections, and demodex mites are some of the possible causes. Swelling from blepharitis can block the meibomian glands in your eyes and reduce the amount of oil they make.
Inward or outward turning of your eyelids. Ectropion is when your lower eyelid turns outward. This turning out of the eyelid exposes your eye to air, which dries it out. Entropion is when your lower eyelid turns in. Your eyelashes may rub against your eye and cause irritation.
Meibomian gland dysfunction. This means your glands don't make enough oil to moisten your eyes, or the oil they make isn't very good quality. Certain medicines or a blockage in the glands can cause meibomian gland dysfunction.
Climate
Temperature, humidity, and wind all contribute to dry eye. Very hot and very cold temperatures may disrupt your tear film. Tears evaporate more quickly when the humidity is low, which is why a humidifier helps with dry eye.
Wind is another trigger because it also dries out your eyes. Any type of blowing air — including air from a hair dryer, air conditioner, or car vent — can make dry eye worse.
Lack of Sleep
If you don't get the recommended seven to eight hours of sleep a night, you’re more likely to have dry eye. Disorders linked to poor sleep, like sleep apnea and insomnia, are also linked to dry eye symptoms.
While you sleep, changes happen to your tear film and the surface of your eye. The tears you make while your eyes are closed protect the surface of your eye and clear away debris. When you don't sleep enough, your eyes don't get these benefits.
Medications
Medicines you may take can affect the function of the meibomian or lacrimal glands that add oil and fluid to your tears. Some medicines in each of these classes cause dry eye:
- Acne medicines
- Anti-anxiety drugs
- Antidepressants
- Antihistamines and decongestants
- Birth control pills
- Blood pressure-lowering medicines
- Cancer medicines
- Glaucoma medicines
- Hormone replacement therapy and birth control pills
- Pain relievers
- Seasonal allergy meds
- Sleeping pills
Health Conditions
Some conditions can cause problems with your tear-producing glands, including:
- Autoimmune diseases like lupus, rheumatoid arthritis, and Sjӧgren's syndrome
- Bell's palsy, which causes paralysis of the face
- Diabetes
- High blood pressure
- Rosacea
- Thyroid disease
Diet
A few nutrients are important for keeping your eyes healthy. One is omega-3 fatty acids, which improves the quality of your tears and helps to maintain the tear film. You'll find these healthy fatty acids in foods like:
- Fatty fish such as trout, herring, mackerel, and salmon
- Canola, flaxseed, sunflower, and walnut oils
- Meats like pork, beef, and lamb
- Low-fat milk and other dairy products
If you don't get enough omega-3s from food, your doctor might recommend taking a fish oil supplement.
These other nutrients also might help protect against dry eye:
- Vitamin A (retinol): Carrots, tomatoes, spinach, dairy products, apricot
- Vitamin B2: Avocados, broccoli, dairy, whole grains
- Vitamin B6: Kale, potatoes, salmon, sardines
- Vitamin B12: Beef, mackerel, dairy products, eggs
- Vitamin C: Peppers, oranges, Brussels sprouts, broccoli
- Vitamin E: Spinach, peppers, mangos, mackerel, wheat germ oil
- Lutein and zeaxanthin: Kale, spinach, romaine lettuce
- Zinc: Whole grains peas, lentils, nuts, dairy
Smoking
This unhealthy habit is linked to a long list of health problems, including cancer, heart disease, and chronic obstructive pulmonary disease (COPD). The many chemicals in cigarette smoke irritate the eyes and reduce the tear film.
You don't have to smoke yourself to experience these effects. Secondhand smoke from a nearby cigarette can be a risk factor for dry eye, too. The mist released from vaping can also be irritating to the eyes.
Surgery
Having eye surgery can correct problems like nearsightedness and cataracts and improve your vision. But these procedures also cause irritation and inflammation in the eye that could leave you with dry eye as a side effect. Some of the eye drops you'll need to take after surgery contain preservatives that also lead to inflammation and dry eye.
LASIK. This is a treatment for vision problems like nearsightedness, farsightedness, and astigmatism. It reshapes the cornea — the clear, dome-shaped surface covering the eye — to improve your vision. About half of people who've had LASIK experience dry eye one week after their surgery. Usually this side effect is temporary, but between 20% and 40% of people still have dry eye symptoms six months after their surgery.
Cataract surgery. A cataract is a clouding of the lens in your eye. It can lead to blurry vision and glare. Cataract surgery removes your clouded lens and replaces it with an artificial lens. Many people who need cataract surgery also have dry eye to begin with, since both conditions become more common with age. Up to one-third of people will have dry eye after their surgery.
Show Sources
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SOURCES:
American Academy of Ophthalmology: "Meibomian Glands," "Tear Film."
CDC: "About Contact Lenses."
Cleveland Clinic: "Computer Vision Syndrome," "Meibomian Gland Dysfunction."
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Johns Hopkins Medicine: "Blepharitis."
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