faq

If you have dry eye — also called dry eye disease or dry eye syndrome — it means something has gone wrong with some part of your tear system or tear film, resulting in compromised eye comfort, eye health, and/or vision.

The tear film, when healthy, is an amazing fluid that normally coats the surface of your eyes and the insides of your eyelids, helping to ensure your eyes are always comfortable and protected and your vision is stable and clear. But suppose something in the system breaks down. The water-producing lacrimal glands are damaged or diseased and don't produce enough water. Or the oil-producing meibomian glands are inflamed and not secreting enough oil to keep your tears from evaporating. Or the goblet cells are depleted, not generating enough mucous to anchor the tears to the eye surface. Or the eyelids aren't closing completely and your tears are evaporating faster than they can be replaced. What happens?

Without healthy, plenteous tears your eyes become uncomfortable and you may have blurry or fluctuating vision, among other things.

For patients, the experience of dry eye tends to be all about sensation. Contact lens discomfort, gritty, irritated or light sensitive eyes send people to their eye doctor. In more severe cases, persistent burning sends them back frequently and goads them through a variety of treatments. The life impact of that burning sensation and other forms of discomfort on people with dry eye is often profound. Among many other things, it can, and did, turn a dry eye drug with a surprisingly low success rate into half-billion-a-year blockbuster.

Of course, nearly everyone occasionally experiences mild dry eye symptoms (irritated, scratchy, gritty or watery eyes) under certain circumstances. That is what people commonly understand the term to mean. But dry eye is a heterogeneous disease — that is, a catch-all term for many things — and traverses a wide spectrum of symptoms and severity. Even when it is not medically serious enough to affect the vision, dry eye can cause an extremity of constant discomfort with a profound impact on function and quality of life, understood only by those who suffer from it. Thus, dry eye is a convenient but medically inaccurate, misleading and in many cases trivializing term that we are stuck with.

If the idea that dry eye could be crippling sounds improbable to you, try holding your eyes open for 60 seconds. Then ask yourself what it might be like for your eyes to feel that way all day.

For a more in depth understanding of dry eye, please see Dry Eye 101. Any unfamiliar terms? See our Dry Eye Glossary.

How many people get dry eye?

5 to 50% of people get dry eye, according to the most current and extensive review of existing research (See TFOS DEWS II Epidemiology report, Abstract).

Why such a wide range? Sounds crazy, doesn't it? It's complicated. Here are just a few of the reasons:

There is no commonly accepted rule for how to measure it. Every study is different.

There's a broad spectrum of severity and a lot of overlap with other conditions.

Geography plays a role. For example, people living at high altitudes, in dry climates and in polluted cities are more subject to dry eye.

Ethnicity plays a role. For example, Asians are considerably more subject to dry eye than non-Asians.

You are more likely to have dry eye if you:

• Are female

• Are older

• Use a computer

• Wear contacts

• Are Asian

Have meibomian gland dysfunction

Have Sjogrens syndrome, or a connective tissue disease

Are frequently exposed to pollution, low humidity; sick building syndrome

Use any of the following medications: antihistamines, antidepressants, anxiolytics, isotretinoin

There are many, many, MANY more things associated with dry eye ranging from thyroid disease to refractive surgery (e.g. LASIK, cataract surgery). These are just some of the most common and most thoroughly documented contributors.

Source: TFOS DEWS II Epidemiology Report