It's common to feel some dryness and irritation in your eyes, especially when you spend a lot of time staring at a computer or other screen. But as you get older, you might notice that your eyes feel dry a lot of the time. That's because dry eye becomes more common as you age.
As the years pass, your body makes fewer of the tears that used to keep your eyes moist. Medical conditions and medications you take could make the tears you do have evaporate faster than usual.
With dry eye, you'll notice symptoms like:
- Stinging and burning
- A scratchy feeling like something is in your eyes
- Red and irritated eyes
- Pain when you wear contact lenses
- Blurry vision
- Sensitivity to light
Dry eyes are also more watery. That might sound strange, but the irritation from dry eye actually makes your eyes produce more tears.
What Causes Dry Eye?
A thin film of liquid called the tear film covers the surface of your eyes and keeps them moist. This film is made up of three layers:
A mucus layer. The bottom layer of the tear film closest to your eye is made from mucus. The conjunctiva, the clear tissue covering the white part of your eye, makes the mucus. The mucus layer helps keep your eye moist.
A watery layer. The middle layer is made of a watery liquid called aqueous fluid, which is your tears. Lacrimal glands in the eyelids make this fluid, which helps to wash away dirt or debris that gets inside the eye.
An oily layer. This is the top layer of the tear film. Meibomian glands in your eyes produce oil that keeps the tear film smooth and prevents your tears from drying up too quickly.
Tear glands constantly send more tears flowing into your eyes to keep them lubricated. Just like the wipers in your car spread washing fluid across your windshield to keep it clear, blinking spreads tears over your eyes to keep your vision clear. Extra tears drain through ducts above your nose.
Dry eye can happen if you don't make enough tears, your tears evaporate too quickly, or both. You're more likely to get dry eye as you age. Often the cause is a medical condition or a medicine you take.
These are the most common causes of dry eye as you get older. Some, like aging, aren't in your control. Others are manageable with lifestyle changes or by taking medicine to treat the cause.
Causes of Decreased Tear Production
One reason for dry eye is that your eyes don't make enough aqueous fluid. Doctors call this condition keratoconjunctivitis sicca. Medical conditions, medications you take, and the aging process itself can lead to reduced tear production later in life.
Aging
Dry eye becomes more common the older you get. While it affects around 8% of people under 60, about 20% of those 80 and older have dry eye. Almost everyone will experience dry eye from time to time after age 65.
Dry eye becomes more common with age because:
- Older adults take more medications
- The eyelids get looser
- The risk of inflammatory conditions increases
- Older eyes have more oxidative stress — an excess of harmful molecules called free radicals that damage cells in the eyes
Women and people who were assigned female at birth (AFAB) are especially likely to get dry eye as they age because of hormonal changes that happen during menopause.
Autoimmune diseases
When you have an autoimmune disease, your immune system attacks your own tissues. That attack creates inflammation that damages various parts of your body. In your eyes, inflammation destroys the goblet cells that produce mucus.
The autoimmune diseases that are most likely to cause dry eye are:
Rheumatoid arthritis. This inflammatory form of arthritis is best known for causing joint damage. The same autoantibodies that attack the joints also affect the eyes. If you don't treat dry eye from rheumatoid arthritis, it could eventually lead to an infection or damage your cornea.
Sarcoidosis. In this condition, the immune system makes too many inflammatory cells called granulomas. Those cells collect and form clumps in your lungs, lymph nodes, heart, and other parts of your body. Granulomas can also affect your eyes. Sarcoidosis inflames the lacrimal glands and reduces their ability to produce aqueous fluid.
Sjӧgren's syndrome. If you have this condition, your immune system attacks the mucus-releasing glands that keep your mouth, eyes, and other parts of your body moist. Sjӧgren's syndrome causes symptoms like dry mouth and dry eyes. People with lupus and scleroderma sometimes have Sjӧgren's syndrome too, which increases their risk for dry eye.
Other medical conditions
Diabetes. This disease can cause problems all over the body. Damage to nerves, kidneys, the heart, and blood vessels are all possible if diabetes isn't well controlled. Diabetes also affects the eyes. Dry eye is one of the most common diabetes-related eye problems, affecting more than half of people with the condition.
Diabetes causes dry eye in a few ways. Consistently high blood sugar damages nerves in the lacrimal gland, which helps you make tears. Elevated blood sugar produces more inflammation, which also damages the lacrimal gland. Finally, your lacrimal gland needs insulin — the hormone that moves sugar from your bloodstream into your cells — to work properly. If your pancreas doesn't make enough insulin, dry eye can result.
Thyroid problems. The thyroid is a gland in your neck. It makes hormones that control your metabolism and other important functions in your body. Diseases that affect this gland make it produce too much (hyperthyroidism) or too little (hypothyroidism) of its hormones.
Thyroid eye disease inflames and damages tissues in the eye. Both hyperthyroidism and hypothyroidism can cause thyroid eye disease. Dry eye is one of the main symptoms, along with eye irritation, tearing, redness, and bulging.
Graft-versus-host disease (GVHD). This is a very serious complication after an organ or stem cell transplant. The donor's cells recognize the recipient's tissues as foreign and attack them. If this attack inflames the lacrimal gland, dry eye can occur.
Vitamin A deficiency. The reason why carrots are often promoted as being good for the eyes is because they're rich in vitamin A. You need vitamin A for clear night vision and to keep your eyes hydrated. You can become deficient in this vitamin if you don't eat enough carrots and other foods containing this vitamin, or if your body doesn't use vitamin A effectively.
Medications
The older you get, the more medical conditions you develop and the more medicines you need to manage them. More than half of adults age 65 and older take four or more prescription drugs. Your body removes medications more slowly with age, increasing the risk for side effects like dry eye.
All of these medicines can cause dry eye or make it worse:
- Antidepressants
- Antihistamines and decongestants to treat colds and allergies
- Beta-blockers for high blood pressure
- Diuretics ("water pills") for treating high blood pressure
- Glaucoma medicines
- Heartburn medicines
- Hormone replacement therapy to treat menopause
- Pain relievers
- Parkinson's disease medicines
- Rheumatoid arthritis medicines like methotrexate (Trexall)
- Sleeping pills
If you take one or more of these medicines, ask your doctor if it could be causing your dry eye.
Lacrimal gland dysfunction
These tear-shaped glands sit above each eye and release the liquid layer of tears that keeps your eyes lubricated. The lacrimal glands need hormones called androgens to work properly. Levels of this hormone drop with age in both men and women. That's why older adults are more likely to develop problems with the lacrimal gland. Because women naturally have lower levels of androgens to begin with, they are at especially high risk for dry eye.
Corneal nerve damage
The cornea is the clear layer of tissue in the front of your eye. It contains nerves that send signals to your body to make tears. When these nerves are damaged by an infection, injury, or medication, you'll make fewer tears. Contact lens use and laser eye surgery can also damage your corneal nerves.
Surgery
Having one of these eye procedures increases your risk for dry eye.
Cataract surgery. This procedure removes your clouded lens and replaces it with a clear one. Cataract surgery can damage the tear film.
Corneal transplant. During this surgery, the doctor replaces your diseased cornea with a healthy one from a donor. Damage to the nerves in the cornea during the procedure can lead to dry eye.
LASIK. This is a treatment for nearsightedness (myopia), farsightedness (hyperopia), and distorted vision (astigmatism). During LASIK, the surgeon creates a flap in the cornea and then uses a laser to reshape the cornea. The procedure may cause dry eye by damaging nerves in the cornea. Up to 70% of people who have LASIK experience dry eye afterward, but the dryness should go away within six months.
Causes of Tear Evaporation
Another cause of dry eye is that the tears you have evaporate too quickly. All of these factors can lead to faster tear evaporation in older adults:
Eye allergies
Allergies and dry eye share symptoms like watery eyes, blurry vision, and light sensitivity. These common symptoms make the two conditions hard to tell apart. Allergies increase your risk for dry eye, and you can have both conditions at the same time.
If you have eye allergies, your body releases the chemical histamine when you're exposed to allergens like these:
- Pollen
- Mold
- Pet dander
- Dust
- Ingredients in skin care products
Some of the antihistamines and decongestants you might take to treat allergies cause dry eye as a side effect.
Eyelid problems
Your eyelids stay closed to keep tears on the surface of your eyes. When they don't close all the way, tears evaporate more easily. These eyelid problems can contribute to dry eye:
- Ectropion: eyelids that turn outward
- Entropion: eyelids that turn inward
- Blepharitis: swollen eyelids
- Floppy eyelid syndrome: loose eyelids
- Retraction: an upper or lower eyelid that's too high or too low
- Lagophthalmos: eyelids that don't close all the way
Parkinson's disease
If you have this brain disorder, your body doesn't make enough dopamine, a chemical that helps your body move. A lack of dopamine makes your eyes blink more slowly, which can lead to dry eye.
Meibomian gland dysfunction
The meibomian glands in your eyelids release oil that's part of your tear film. Meibomian gland dysfunction (MGD) happens when these glands don't make enough oil or the oil they do produce is poor quality.
MGD is something that you're either born with or that develops later in life. It may be related to conditions like rosacea and graft-versus-host disease, a serious complication that can happen after an organ or stem cell transplant.
Rosacea
This skin condition also affects the eyes. Ocular rosacea causes dryness, redness, burning, and other eye symptoms. Although some people have both skin and eye rosacea, it's possible to have it in your eyes only.
Contact lenses
Wearing contact lenses to improve your vision could lead to dry eye. Regular contact lens use could damage the mucus-producing goblet cells in your eye. Up to half of people who use contact lenses stop wearing them within three years, most often because of irritation like dry eye.
The environment
Tears evaporate more quickly in windy or dry conditions. Smoke from a fire or cigarettes irritates eyes and reduces tear production. Regular exposure to smoke could make dry eye symptoms worse.
Staring at a computer screen or TV for a long time without blinking also dries out the eyes more quickly. Taking breaks at regular intervals to look away from your screen will prevent your eyes from drying out.
Show Sources
Photo Credit: iStock/Getty Images
SOURCES:
American Academy of Ophthalmology: "Dry Eyes After Laser In Situ Keratomileusis (LASIK)," "Ocular Graft Versus Host Disease," "Tear Film," "What is Dry Eye? Symptoms, Causes and Treatment."
American Diabetes Association: "Eye Health: Dry Eye With Diabetes."
American Optometric Association: "Dry Eye."
Cleveland Clinic: "Computer Vision Syndrome," "Cornea Transplant," "Dry Eye," "Meibomian Gland Dysfunction," "Thyroid," "Thyroid Eye Disease," "Xerophthalmia."
Clinical Optometry: "Contact Lens Wear and Dry Eyes: Challenges and Solutions."
Clinics in Chest Medicine: "Ocular Sarcoidosis."
Dean McGee Eye Institute: "How to Tell the Difference Between Dry Eye and Allergies."
Expert Review of Ophthalmology: "Post-LASIK Dry Eye."
Johns Hopkins Medicine: "Can Smoking Affect Your Eyes?" "Dry Eye."
Journal of Ophthalmology: "Aging: A Predisposition to Dry Eyes."
Kaiser Family Foundation: "Data Note: Prescription Drugs and Older Adults."
Mayo Clinic: "Diabetes," "Dry Eyes," "LASIK Surgery: Is it Right for You?" "Ocular Rosacea," "Rheumatoid Arthritis: Can It Affect the Eyes?" "Sarcoidosis."
Medline Plus: "Sjogren's Syndrome."
StatPearls: "Anatomy, Head and Neck: Eye Lacrimal Gland," "Graft-Versus-Host Disease."
