What is dry eye?
Dry eye occurs when the eye does not produce tears properly, or when the tears aren't of good quality and evaporate too quickly. Dry eye can make it more difficult to perform some activities, such as using a computer or reading for an extended period of time, and it can make some environments uncomfortable, such as the air inside an airplane. Other names for dry eye include dry eye syndrome, keratoconjunctivitis sicca (KCS), dysfunctional tear syndrome, lacrimal keratoconjunctivitis, evaporative tear deficiency, aqueous tear deficiency, and LASIK-induced neurotrophic epitheliopathy (LNE).
In some cases, dry eye can cause inflammation of the eye's surface. Without treatment, this can lead to pain, ulcers, or scars on the cornea (the clear, dome-shaped outer surface that covers the center of the eye), and some loss of vision. But permanent vision loss from dry eye is uncommon.
How do tears relate to dry eye?
Tears are necessary for overall eye health and clear vision. Tears bathe the surface of the eye, keeping it moist, and wash away dust and debris. They also help protect the eye from bacterial and other types of infections.
Tears are made of proteins, electrolytes, and vitamins that are important for eye health and preventing infection. Tears have three main parts, which include:
- Outer, oily, lipid layer
- Middle, watery, layer
- Inner, mucous or mucin layer
Any disease or condition that changes the components of tears can make them unhealthy and result in dry eye.
Are there different types of dry eye?
Yes. Types of dry eye include:
- Aqueous tear-deficient dry eye - This is a disorder in which the eye does not produce enough of the watery part of tears.
- Evaporative dry eye – This disorder is caused by inflammation of the glands that produce the lipid or oily layer of tears. Without this layer, tears can be unstable and evaporate too quickly.
What are the causes of dry eye?
Dry eye can be caused by several factors, including:
- Inflammation of the surface of the eye, the lacrimal gland, or the conjunctiva
- Any disease that affects the tear's components
- An increase in the surface of the eye – This can happen in thyroid disease when the eye bulges forward.
- Cosmetic surgery – Dry eye can happen if the eyelids are opened too widely
- Skin disease on or around the eyelids
- Diseases of the glands in the eyelids, such as meibomian gland dysfunction
- LASIK surgery – These symptoms usually last three to six months, but can last longer.
- Not blinking enough – This can happen when staring at computer or video screens.
- Vitamins – Dosages that are either too high or too low can cause dry eye.
- Homeopathic remedies
- Loss of sensation from long-term contact lens wear
What are the symptoms of dry eye?
Dry eye can cause the following symptoms in the eye:
- Stinging or burning
- A sandy or gritty feeling, as if something is in the eye
- Periods of excess tears that happen after periods of dryness
- Stringy discharge
- Pain and redness
- Periods of blurred vision;
- Heavy eyelids
- Inability to cry
- Uncomfortable contact lenses
- Difficulty reading, working on the computer, or any activity that requires focused vision;
- Eye fatigue
If you have any of these symptoms over a period of time, see an eye doctor. He or she can diagnose and treat your condition. This can prevent permanent damage.
Are there risk factors for dry eye?
Dry eye is a common condition, but it is particularly likely in elderly people and women after menopause. Women who have early menopause are more likely to have eye surface damage from dry eye.
Other risk factors for dry eye include:
- Taking certain medications, such as antihistamines, nasal decongestants, tranquilizers, certain blood pressure medicines, Parkinson's medications, birth control pills and anti-depressants. Women who use hormone replacement therapy are also more likely to get dry eye.
- Certain immune system disorders such as Sjögren's syndrome, lupus, and rheumatoid arthritis
- Exposure keratitis, a condition in which the eyelids do not close completely during sleep
What can I do to help my dry eye?
In many cases, using over-the-counter artificial tears, gels, gel inserts, and ointments is a good first step. These can help relieve symptoms and provide an important source of tears, especially in people who do not produce enough. Avoid artificial tears with preservatives if you need to apply them more than four times a day and products with chemicals that cause blood vessels to constrict.
Wearing glasses or sunglasses that fit close to the face (wrap around shades) or that have side shields can help slow tear evaporation and keep the eye moist. Indoors, an air cleaner to filter dust and other particles can help dry eyes. A humidifier can also help by adding moisture to the air.
Avoid dry conditions and allow your eyes to rest when performing activities that require you to focus your vision for long periods of time. You can also use lubricating eye drops while performing these tasks.
How is dry eye treated?
Treatments can be different depending on the cause of dry eye.
Many treatments involve treating the underlying source of the dry eye. If your dry eye is caused by another disease or condition, your doctor will treat that condition. Or, if your dry eye is from taking a medication, your doctor might recommend switching to a different medication. If contact lens wear is the problem, your eye doctor might recommend another type of lens or reducing the number of hours you wear your lenses. In the case of severe dry eye, your doctor might advise you not to wear contact lenses at all.
Other treatment options for dry eye include:
- Medication - Cyclosporine, an anti-inflammatory medication, is the only prescription drug available to treat dry eye. It reduces corneal damage, increases tear production, and helps with symptoms of dry eye. It might take three to six months for the medication to work. In some cases of severe dry eye, the doctor might recommend short term use of corticosteroid eye drops to decrease inflammation.
- Lacrimal plugs – This treatment involves plugging the tear drainage holes. These are small circular openings at the inner corners of the eyelids where tears drain from the eye into the nose. Lacrimal plugs, also called punctal plugs, can be inserted painlessly by an eye doctor. The person usually does not feel them. Some types of plugs are temporary, but others are permanent.
- Punctal cautery – This is a simple surgery for severe cases of dry eye that permanently closes the drainage holes. This helps keep the small amount of tears on the eye for a longer period of time.
- Diet and supplements - In some patients with dry eye, supplements or dietary sources (such as tuna fish) of omega-3 fatty acids (especially DHA and EPA) might help with symptoms. Talk to your primary care doctor before using nutritional supplements or vitamins.
This information was developed by the National Eye Institute (NEI) to help patients and their families in searching for general information about dry eye. An eye care professional who has examined the patient's eyes and is familiar with his or her medical history is the best person to answer specific questions.