What Is Dry Eyes?

by Donna and Romie Walker

The cause for dry eyes (keratoconjunctivitis sic'ca) is simply the lack of lubricating tears. If the environmental conditions are proper and the eye and its supporting functions are healthy the eye will be bathed with a lubricating tear film. With the disruption of any or all of these you will have scratchy, burning and stinging eyes, which is commonly referred to as dry eyes.

Our normal bodily functions create two types of tears. Crying and watering of the eyes create tears called reflex tears. The other tears that are made are lubricating tears. These are the tears that are formed as a film on the eyes which are intended to keep the eyes lubricated. The tears are not noticeable, but under normal conditions they are there doing their job.

The first signs of dry eyes or the lack of lubricating tears will be the burning, stinging and scratchy feelings. The eyes may water during this time but it will not help because these are reflex tears and not lubricating tears.

The causes for the keratoconjunctivitis sic'ca can be several things. One of the causes is aging; as we get older there is less tear production. Even the heat and air systems in our homes can cause the eyes to be dry. Wind, smoke and low humidity will cause dry eyes. There are several medications that cause the eyes to become dry.

Problems with the lids of the eyes, rheumatoid arthritis and eye injuries can cause dry eyes. Glands located in the upper portion of the eyelid produce lubricating tears, which flow over the eye surface. The tears drain from the eyes into canals leading into the nose.

To determine the causation of the eyes being dry, the optometrist will need information about the patient's over all health. Then he/she will examine the film of tears on the eyes and calculate the production levels of the tears.

When informing the doctor about the history of your health make sure all medical conditions are discussed. There are many conditions that can affect the product of adequate tears. The optometrist will need full disclosure of all medications being used, to include antihistamines and drops for the eyes. If you wear contacts, the doctor will need to know the type and how often you wear them.

The doctor will examine the eyes with a unique microscope referred to as a slit lamp. This will show the tear film and in conjunction with eye drops containing dye, any dry spots will show.

The doctor will also measure the production of eye tears. Anesthetic drops may be used to numb the eyes before filter papers are folded over the lower lids. The eyes must remain closed for approximately five minutes while the tear film is absorbed into the paper. The total fluids absorbed are an indicator of tear production.

Treating dry eyes with artificial tears is the most common prescription. In severe cases where the artificial tears don't give relief for the condition, there may be a need to put in plugs or use surgery to stop excessive draining to increase tear film.