A new test to promote healthy contact lens wear

The cornea is the transparent dome in the center of your visual system. This dome allows light to enter into the eye without aberration.

It is very important that the cornea remains transparent and maintains a certain thickness. If the cornea transparency is lost and it increases in thickness, the cornea will result in blurry vision.

The first layer of cells on the cornea is called the epithelium and its main function is to protect the front of the cornea. These cells are very similar to skin cells; they constantly multiply from the inside, as the cells on the outside flake off. This maintains a layer of healthy cells at all times.

On the back of the cornea there is a single layer of cells called the endothelium. This layer acts as a water pump and a barrier. Its main function is to maintain the correct amount of fluid with nutrients in and out of the cornea. If this pumping function fails, the cornea will start to increase in thickness and the transparent cornea will become cloudy. It is possible for the cornea to become so cloudy or opaque that loss of vision could occur. Then it becomes necessary for the cornea to be replaced by means of a cornea transplant, a very serious operation.

What causes the endothelial cell layer function to fail? Unlike the cells in the front of the cornea, the cells in the back of the cornea do not reproduce themselves. When cells die, the number of cells that are left decreases. The remaining cells must increase in size in order to fill the gaps caused by cell loss. Cell loss are caused by diseases, trauma, or trauma caused by an eye operation. But scientists recently have discovered that contact lenses can cause changes in the endothelial layer from lack of oxygen.

Contact lenses reduce oxygen penetration into the eye because the material covers the cornea. The lack of oxygen causes chemical changes to occur at the bottom layers of the epithelium. These changes produce a chemical that travels through the cornea and attacks the endothelial cell layer. The chemical kills some of the cells and changes the shape and size of those that remain.

The amount of damage varies from person to person depending on the type of lens, the length of time the person has worn the lenses and the individual’s own genetic makeup. The only way for your eye doctor to determine the condition of those cells is to use a very special microscope that is called a Specular Microscope or Cell Counter or ECC. This microscope does not touch your eye in any way; it takes a photo of this important layer. It focuses on the back of the cornea utilizing an invisible infrared beam and takes three seconds to capture a picture of your endothelial cells.

By looking at the picture of your cells, your eye doctor can determine if your contact lenses need to provide the cornea more oxygen.

Ask your doctor at Davis EyeCare Associates the next time your in the office and find out if your contact lenses are causing changes in the endothelial cell layer in your eye. If the test shows that the contact lens is stressing your eyes, we will change your contacts with one of the new healthy hybrid designs which will provide more oxygen to the eye. Davis EyeCare is in the business of protecting your sight and maintaining healthy eyes.