University of Michigan Kellogg Eye Center | 1000 Wall Street, Ann Arbor, MI 48105 | 734.763.8122
Copyright © Regents of the University of Michigan
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| Laser Eye Surgery Seeing Better with The Speed Of Light  These days, it seems that everywhere we go we meet someone who has had laser eye surgery. These people, now free from eye glasses and contact lenses, have been spreading the praises of these high tech procedures throughout our communities. But, how do these procedures really help us see better? Maybe a little background will help.How We See When light passes through the round, convex, transparent structure called the cornea, the light is bent (that is, refracted). It is refracted further by the eye’s lens so that it focuses on the retina in the back of the eye. The distance the light travels determines whether we see that big “E” clearly, whether it is blurred, or whether we can figure out any of those letters on the chart at all. Depending on the shape of the cornea, some of us are nearsighted, some of us are farsighted, and some of us have astigmatism because the light from images we want to see has not been bent – or refracted – properly. Refractive errors, as these are called, affect a large portion of the population. Most are easily correctable. Traditional Approaches to Treatment Glasses are the most common way to correct refractive errors and have been used for centuries throughout the world with great success. Contact lenses though first described by Leonardo da Vinci, were not actively used until the 1930’s. They became popular in the late 1950’s as newer plastics made them more comfortable and safer to wear. Today, contacts are worn by nearly 30 million people in the U.S. Surgical Procedures In the mid 1930’s a Japanese ophthalmologist was asked by the Emperor to rid imperial army recruits of their nearsightedness. Rather than use glasses to refract the light before it hit the cornea, he decided to try something new. Why not re-shape the cornea itself? His procedure involved making a number of small incisions at various intervals on the cornea. Although we may shudder to think what it was like for those first recruits, this technique was employed into the early 1960’s. In 1979, a Russian ophthalmologist adapted this process and coined the phrase radial keratotomy. It turned out to be an effective way to treat nearsightedness. Radial keratotomy was used throughout the ’80s and into the ’90s with varying degrees of success in this country and around the world. From Scalpels to Lasers Over the past 20 years as ophthalmic uses of medical lasers have been studied, it has occurred to many ophthalmologists that lasers could be used to re-shape the cornea. Laser burns, as they are called, could produce the desired effect with greater accuracy and with less weakening of the eyeball itself. In refractive surgery procedures, a laser that emits a cool beam “fires” on the cornea. As microscopic areas are vaporized by the laser, the shape of the cornea is altered, allowing images to pass through the cornea and arrive at the proper spot on the retina so that we can see them clearly. Thus was born the laser procedures that we hear so much about today. PRK and LASIK The PRK (photorefractive keratectomy) procedure, which was developed in the late 1980’s, uses the laser beam to treat the surface of the cornea. Treating the surface layer, however, can cause problems and, because that layer has an abundance of nerve cells, PRK can be uncomfortable as patients recover from the surgery. In addition, the surface is sensitive to change and healing is relatively slow. Ophthalmologists spent many years working on ways to solve these problems and by the end of the ‘90s, LASIK (laser-assisted in situ keratomileusis) had become the procedure of choice. With LASIK, the theory is the same except that the laser beam does not disrupt the sensitive surface of the cornea. Instead, a hinged flap is created. The ophthalmologist folds the flap back to allow the laser bursts to sculpt the deeper layers of the cornea directly. These layers do not have the sensitivity of the surface layer. Then the flap is returned to its original position to heal. No stitches are required. Results from LASIK can be dramatic. Vision usually improves almost immediately. Patients experience less pain. Healing is faster. Other Options: Corneal Ring Segments Research into ways to improve refractive surgery techniques is ongoing. Recently a new technique, which does not involve lasers, became available to the public. Corneal ring segments (manufactured under the name “Intacs”) are synthetic rings, made from the same material used to make contact lenses, which are implanted in the cornea. How the Rings Correct Vision Corneal rings are surgically placed through a tiny incision that is made in the cornea. Once in place, the two arcs flatten the cornea so that light rays can properly focus on the retina. Since the rings are inserted in the outer edge of the cornea, the center of the cornea remains untouched. Once in place, these rings change the shape of the cornea from the inside with the use of prescription coils. Corneal rings can be removed if the patient desires or can be replaced later if necessary with rings of a different prescription. What’s the Best Choice for You? LASIK today has become the most common option for refractive surgery. For those whose anatomy or physiology would make LASIK difficult, PRK may still be an option. Corneal rings may be a good choice for some, however, they can only be used for people with mild forms of nearsightedness. Answers to Your Questions You’ll certainly have many questions if you are considering refractive surgery. The staff at the Kellogg Eye Center will be happy to speak with you about your options so that you can make an informed decision. If you are interested in speaking with us about refractive surgery, please call (734) 615-6914. |
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University of Michigan Kellogg Eye Center | 1000 Wall Street, Ann Arbor, MI 48105 | 734.763.8122
Copyright © Regents of the University of Michigan |