Your Eyesight Changes
You are able to see objects by a complex process. As light bounces off objects it is reflected and picked up by your cornea. The American Optometric Association states that, "For clear vision to occur, the cornea must have the correct shape and power to focus incoming light rays precisely on the retina at the back of the eye." Changes to the shape of your cornea will alter its ability to bend incoming light at the correct angle. This means the image you are seeing can not be focused on the retina. Your retina is responsible for interpreting the images and then sending them to the brain.
The Cornea is Mishapen
If your cornea is no longer shaped correctly you may need surgery. Corrective laser surgery can be used for conditions such as myopia (can not see items far away), hyperopia (can not see items that are close) or astigmatism, where your sight in general is blurred. You will need to have a consultation with a specialist to determine whether you are a candidate for this procedure. The two main types of laser eye surgery are Lasik and PKR. Your doctor will help you to decide which method is best for you.
Lasik Surgery Procedure
During the procedure you will lie in a reclining chair or on a table and drops will be placed into your eyes to numb the area so you will not feel pain. Your surgeon will flush your eyes and then use a lid speculum to help keep your eyes open. Pressure is placed on the eye and you will need to keep your gaze fixed to help keep the eyes centered. Then your surgeon will either make a small incision in your cornea using a device called a microkeratome or use a bladeless technique with high-energy lasers. This bladeless technique is called Wavefront and it produces a three dimensional "map" about how your eyes focus the light and create images. This allows the surgeon to make precise changes to your cornea to improve your sight.
Cornea is Reshaped
During Lasik surgery, an excimer laser will be used to reshape your cornea. The laser evaporates a small amount of corneal tissue. This removal of corneal tissue reduces the cornea's curvature. As the shape of the cornea is corrected, your eye will once again be able to focus and control light as it did before your eyesight changed. If successful you will be able to see without corrective devices.
PRK Technique
Photorefractive Keratectomy corrective laser surgery, or PRK, can be used in cases where the cornea is too thin, the pupils are large or in those patients who are not good candidates for Lasik. This procedure also uses an excimer laser. However, instead of evaporating the tissue as in Lasik, cool ultraviolet light is used to remove small amounts of tissue to reshape the cornea. PRK surgery may produce more discomfort then Lasik and your vision clears more slowly than with Lasik. The benefits of PRK are that the procedure takes less then one minute and can be a good alternative for those who can not have the Lasik technique.
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