Can eye drops help?
Eye drops help relieve the symptoms and in some cases the causes of dry eyes in several ways. On a most basic level they act as a lubricant and supplement reduced or replace absent tears. However, research over the years has refined this and discovered that the make-up of the solutions used can do far more. In some cases going to the root cause of the condition, for far superior effect. |
 | The 1970's
In the 1970's, polymers were added to artificial tear solutions (all containing a preservative at the time) to improve their lubricant properties and change their viscosity. Solutions of higher viscosity remain in the eye longer. The relief preserved artificial tear solutions provide hinges on their ability to temporarily stabilize the cornea-tear interface. |
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 | The 1980's & 90's\
In the late 1980's preservative-free artificial tear solutions arrived following the discovery that preservatives increase the rate of corneal cell loss. So although early preserved artificial tears help stabilize the tear film, the preservative actually reduced the corneas own natural functions. The preservative free version redressed this, but did not tackle the corneal damaged caused by the condition of dry eyes itself. |
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 | Today
Since then, researchers have tried to improve the effect of these preservative-free solutions on corneal function by adding various ions. The living cells that comprise the surface of the eye don't have a blood supply. Instead they depend on the tear supply for two crucial life requirements: Oxygen and electrolytes. The tear film receives oxygen by direct absorption from the air and electrolytes through active secretion by the lacrimal glands. |
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| The electrolyte balance has been shown to be crucial for maintaining conjunctival goblet cells which lubricate and defend the ocular surface. They work in response to pain, changes in temperature and changes in electrolyte balance from that which is native in the tear film. Mucus fired from goblet cells helps trap foreign matter and expel it from the eye. One of the most important changes to occur in dry eyes is a reduction in the number of conjunctival goblet cells on the surface of the eye. New eye drops therefore work to try and restore this balance in electrolytes as well as moisturizing and lubricating the eye. |
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Other Options
For more severe cases of dry eye, in which the cornea is inflamed, anti-inflammatory agents are sometimes prescribed. Topical steroids (in eye drops) are safe for short-term use, to combat inflammation, but can cause side-effects when used for a long time. A current research area is how to actively suppress inflammatory mechanisms, rather than just passively lubricate the surface of the eye.
Tears drain out of each eye and into the nose, through a small channel. For some forms of dry eye, tiny plugs can keep tears on the eye's surface by slowing the rate of drainage from the eye; this procedure is called punctal occlusion. |
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