Dry eye syndrome is lack of sufficient lubrication and moisture in the eye. It may cause subtle but constant irritation to the tissues of the eye.

Persistent dryness, scratching and burning in eyes are signs of dry eye syndrome. Some people also experience a "foreign body sensation," the feeling that something is in the eye. And it may seem odd, but sometimes watery eyes can result from dry eye syndrome, because the excessive dryness works to over-stimulate production of the watery component of your eye's tears.

Tears bathe the eye, washing out dust and debris and keeping the eye moist. They also contain enzymes that neutralize the microorganisms that colonize the eye. Tears are essential for good eye health. In dry eye syndrome, the eye doesn't produce enough tears, or the tears have an altered chemical composition that causes them to evaporate too quickly.

Dry eye syndrome has several causes. It occurs as a part of the natural aging process; as a side effect of many medications, such as antihistamines, antidepressants, certain blood pressure medicines, Parkinson's medications, and birth control pills; or living in dry, dusty or windy climate. Home or office has air conditioning or a dry heating system can also dry eyes. Another cause is insufficient blinking, while staring at a computer screen all day. Dry eyes are also a symptom of systemic diseases such as lupus, rheumatoid arthritis, rosacea or Sjogren's syndrome

Long-term contact lens wear is another cause; in fact, dry eyes are the most common complaint among contact lens wearers. Dry eye syndrome makes contact lenses feel uncomfortable, and the rubbing of the lenses against the conjunctiva seems to be a cause of dry eyes. Many eye drops, especially some formulations of artificial tears, cannot be used with contact lenses are in the eyes. The lenses will have to be removed, and re-inserted 15 minutes after instilling the eye drops.

Recent research suggests that smoking, too, can increase the risk of dry eye syndrome.

Primary aim of the treatment is to alleviate the dryness, scratchiness and burning sensation. Artificial tears are lubricating eye-drops that may help. Immunomodulants like cyclosporine go one step further: they help the eyes to increase tear production.

Please check with your ophthalmologist before buying any over-the-counter eye drops.