When most people think of tears, we think about the water droplets that drip from our eyes when we are upset or cutting onions. Those are typically called “reflex tears” and is one of our body’s way of protecting itself.
But the front surface of our eyes, are constantly covered by a thin film of tears that is an important part of our vision system and eye health. The reason we blink is actually to keep this constant tear film evenly spread out across the front surface of the eye.
“Dry Eye” is a collection of eye conditions related to the breakdown of this tear system and can lead to discomfort, reduced vision and even long term damage to the eye. In this article, we will cover the factors that are necessary to maintain a healthy tear film, many of the causes of Dry Eye and some of the available treatments to alleviate the symptoms and protect the eye.
When our tears are functioning properly, they protect our ocular surface from the dust, allergens and other pollutants that are constantly in the air. They also provide a smooth surface to accurately focus the light into our eyes so that we are able to see clearly. Healthy tears are made up of three distinct layers that must be in the right proportions to function properly:
- Mucin layer is secreted by the tissue on the surface of the eye itself and helps the tears spread evenly across the ocular surface.
- Aqueous layer is the thickest layer and made of water. It is secreted by the lacrimal gland that rests above the eye.
- Lipid layer is the outer most part of the tears. It prevents evaporation of the water in the aqueous layer. It is secreted by the meibomian glands in the eye lid.
A deficiency in any of these layers can lead to dry eye symptoms and if left untreated can cause damage to the eye’s surface. Symptoms of dry eye typically begin with some type of discomfort, especially when performing visually intensive tasks like using a computer or driving. The discomfort may be described as burning, stinging, or a sandy, gritty feeling in the eyes. Other symptoms may include redness, excessive watering (those are the reflex tears), blurry vision that “comes and goes”, eye strain or an intolerance of contact lenses.
Dry Eye is a growing problem in today’s society and there are a number of factors contributing. Many medications cause a decrease in the body’s ability to secrete tears as do certain skin conditions. Poorly fit contact lenses or using the wrong contact lens solutions can also be a factor. Certain eye surgeries, extended computer use, travel in airplanes, allergies, pregnancy, damage around the eye, increased pollution, aging and vitamin deficiency can all contribute to the incidence of Dry Eye.
The best treatment for Dry Eye depends on the root cause of the problem. Prescription medications are available for those with deficiencies in certain tear layers. Prescription eye wear is available for those who use a computer more than three hours per day. Changes in contact lens materials or solutions can also aid in dry eye treatment. Many patients benefit from supportive treatment of the ocular surface and nutritional therapies. Plugs into the tear drainage ducts or therapeutic lenses can be used in extreme cases.
To Learn More about Dry Eye – Visit the National Institute of Health