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More than 1½ million people in the United States will have some form of refractive vision correction in the year 2000. Most of those procedures will be performed with an Excimer laser. Every patient who would like to have the procedure, however, is not a good candidate, and a thorough examination by a qualified ophthalmologist or optometrist is necessary to determine suitability for surgery.
In addition to undergoing a complete general eye exam, anyone interested in having refractive eye surgery will need to visit with an eye doctor about their expectations for improved vision following the procedure. Even those who qualify physically for the surgery should remember that their vision after surgery will probably be no better than when wearing corrective eyeglasses or contact lenses. People choose to have the procedure for cosmetic or occupational reasons or because they are tired of taking care of, or keeping up with, glasses or contacts lenses.
Many who are interested in vision correction surgery attend a seminar to learn more about the procedure before their first visit with the eye doctor. The seminars are usually designed to explain the various options and may even provide the opportunity for a preliminary vision screening. Anyone interested in laser vision correction surgery should take the time to attend a seminar, read relevant literature or become otherwise educated about the options, risks and potential benefits of the procedures, before scheduling an appointment.
The use of the Excimer laser has been approved by the FDA for nearsightedness for up to -12.00 diopters with up to 4 diopters of astigmatism, and for farsightedness between +1.00 and +6.00 with less than 1 diopter of astigmatism. Each patient must, however, be evaluated individually because factors such as corneal thickness may also affect the patient's eligibility for laser eye surgery. Other refractive surgery procedures may be available for patients outside the acceptable ranges for laser surgery.
Patients should bring their current eyeglasses, previous eyeglasses or contact lenses to the exam. Most doctors ask that soft contact lenses not be worn for three to six days and hard contacts for at least two weeks prior to the exam. This allows the surface of the cornea to resume its normal shape, a necessary prerequisite for accurate measurements of the shape of the cornea in preparation for surgery. Insurance information should also be brought to the examination, although most insurance plans do not cover refractive surgery. A medical history will be taken, so patients should bring any relevant information regarding medications being taken or any existing medical conditions that might effect surgery. Because a dilated exam will be performed, it's a good idea for patients to bring sunglasses for the drive home.
The laser vision correction exam, which will take about two hours, includes tests for visual acuity, refraction, and an evaluation of ocular health. In addition, a microscopic examination of the eyes will be performed. This test produces a full-color corneal map of the surface of the cornea. This procedure, called corneal topography, creates detailed maps of the surface of the eye using an instrument that combines a computer and video camera. The maps resemble geologic relief maps with each color representing a different steepness of curvature. This test is especially important because it affects the amount of ablation, or vaporizing of the corneal tissue, the surgeon will perform during the laser vision correction procedure.
Other tests that may be performed include:
Following completion of the tests, the eye doctor will spend several minutes with the patient to discuss test results and whether refractive surgery is likely to fulfill expectations for improved vision. If the patient decides to proceed with a refractive surgery procedure, the doctor will explain potential risks and complications of surgery, the expected visual results, and what a patient should expect to hear, feel and see during surgery. If the examination has been performed at an ophthalmologist's office, the patient will normally be referred to a refractive surgery coordinator for scheduling of surgery and to be given pre-operative instructions. If the exam takes place at an optometrist's office, the patient will be referred to an ophthalmologist for surgery.
The doctor's office or surgery center normally provides complete pre-operative instructions to a patient preparing to have refractive surgery. This will include when to discontinue the use of contact lenses, the signing of consent forms, the possible use of antibiotic drops for several days prior to surgery, and any other special instructions that prepare the patient for the day of surgery.
See Laser In-Situ Keratomileusis (LASIK), Photorefractive Keratectomy (PRK) and Refractive Surgery in the Eye Care Encyclopedia.
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