What are dry eyes?

What are dry eyes?

The eye depends on the presence of a tear film to provide constant moisture and lubrication to maintain vision and comfort. Tears are a combination of:

• Water, for moisture
• Oils, for lubrication and to prevent evaporation of tear liquid
• Mucus, for even spreading of tears on the surface of the eye
• Antibodies and special proteins, for resistance to infection

These components are secreted by special glands located around the eye. When there is an imbalance or deficiency in this tear system, or when the tears evaporate too quickly, a person may experience dry eye.

When tears do not lubricate the eye enough, you may have the following in your eye:

• Pain
• Burning
• A gritty sensation, like a feeling of a foreign body or sand
• Itching
• Redness and blurring of vision

Sometimes, a person with dry eyes will have excess tears running down the cheeks, which may seem confusing. This happens when the eye isn't getting enough lubrication. The eye sends a distress signal through the nervous system for more lubrication. In response, the eye is flooded with emergency tears.

However, these tears are mostly water and do not have the lubricating qualities or the rich makeup of normal tears. They will wash dirt away from the eye, but they will not coat the eye surface properly. In addition, because these emergency tears tend to arrive too late, the eye needs to regenerate and restore itself, and treatment is necessary.