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How PRK works
Through research and technologic innovation, it has been discovered that a very specific wavelength of far-ultraviolet light energy will literally vaporize fractional layers of human cells, leaving an incredibly smooth undamaged tissue surface. This precise technology has been named the Excimer laser, and achieves an accurate, computer-directed, surgeon-controlled cornea surgery using this precise cold laser beam. Using cold waves means that the surrounding tissue is not affected. Tissue is vaporized by breaking molecular bonds at the tissue surface.
With this unmatched ability to remove tissue, the Excimer laser has been rapidly adopted as a prominent tool for either therapeutic treatment (phototherapeutic-PTK), or for refractive treatment (photorefractive-PRK) surgery correction.
Candidate excimer laser PRK
In the broadest terms, a candidate for successful PRK should be at least 20 years of age, have an eyeglass prescription which has been stable for at least one year, have healthy eyes which are free from hereditary or acquired diseases and have realistic expectations for laser-refractive surgery and its ability to reduce or eliminate the need for glasses or contacts. These guidelines ensure that only those patients for whom laser-refractive surgery is most appropriate will consider proceeding with this treatment.
PRK success rates
PRK has a ten year history of clinical success. The majority of patients that undergo PRK will find that their final uncorrected vision is similar to what they had with glasses or with contact lenses. Its safety and efficacy have been established by over 300,000 patients treated in approximately 47 countries.
98% of myopic (nearsighted) patients can expect vision of 20/40 or better within one year. 82% can expect vision of 20/25 or better. These statistics are slightly better for patients with lower levels of myopia and slightly worse for those with higher refractive errors. In a recent survey, 95% of all patients that undergo PRK laser surgery would decide to do it again.
EXCIMER LASER PRK VS. RK REFRACTIVE SURGERY
Many patients considering refractive surgery are interested in comparing the advantages of Excimer laser surgery (PRK) over refractive or radial keratotomy (RK). The Excimer laser is the latest technique. PRK is computer-assisted laser surgery for refractive correction.
RK works by relaxing or weakening the curvature of the cornea. With RK, radial surgical cuts are placed manually in the corneal surface. Patients that undergo RK generally heal quickly; however, since the front of the eye has been surgically cut, extra caution is required in the future in regard to trauma.
With the laser the central cornea is reshaped without any alteration to corneal strength, thus, without extra caution in regard to future trauma; however postoperative healing takes considerably longer with PRK.
PRK Complications and side effects
From worldwide experience with Excimer laser refractive surgery, there appears to be minimal risk associated with its use. As with any surgery, there can be an unexpected individual responses which may delay or prevent achievement of your desired visual result. The thin outer layer of rapidly-growing cells coating the cornea must be painlessly removed as a part of the laser surgery. This layer usually grows back very rapidly, being completely restored in two to three days. In rare circumstances, patching of the eye or other treatments may be required to encourage more rapid healing.
It is common to experience some initial minor irritation and light sensitivity following laser surgery. Both symptoms generally resolve quickly. Uncommonly, it is possible to develop a superficial microscopic corneal haze, which also typically resolves in a short period of time.
Final visual results vary depending upon differing individual degrees of nearsightedness, astigmatism and also upon the healing characteristics that vary from person to person. Generally, those with lower degrees of refractive error obtain optimum vision in the shortest period of time. It is uncommon, but possible, to have some unresolved overcorrection or undercorrection. This outcome may require eyeglasses or contact lenses in order to achieve optimum visual performance. It is often possible to perform a secondary laser enhancement to attempt to improve this outcome.
PRK Pre op instructions
Unless previously instructed otherwise, do not wear soft contact lenses ONE WEEK prior to your surgery; do not wear hard or gas permeable contact lenses TWO WEEKS prior to your surgery. There are no restrictions on eating, drinking, or taking medication prior to surgery, other than avoiding alcohol and any medication that may produce drowsiness. Wear comfortable clothing and do not wear eye make-up. It is required that all patients bring a driver or arrange for alternate transportation. Please plan for a recovery time of at least one hour following the procedure.
Upon arrival for PRK surgery, your eye will be prepared with a special surgical cleansing solution and preoperative medications will be administered to guard against infection. Anesthetic drops, to fully numb your eye, will be added to assure your total comfort. No needles will be utilized. During the procedure, you may be asked to look at a light to help hold your eye still.
The entire procedure takes only a few minutes. In fact the actual laser application takes 15 to 60 seconds to complete. You will be allowed to leave approximately one hour following surgery. Please arrange for a family member or a friend to drive you home following surgery. Upon arriving at home, you may wish to take a nap to allow your eye to begin healing while you remain comfortable.
PRK post op instructions
Patients may experience slight discomfort during the first 24-48 hours following surgery. A protective "bandage" contact lens placed on the eye for the first day, combined with soothing drops, keeps any irritation to a minimum. You will be ready to return to normal activities within a short time with only a few restrictions. It is advised that you stay home from work for two days. In the first two weeks, no makeup, no swimming, no bending over type activities, like gardening, and no contact sports.
CANDIDATE - PRK ENHANCEMENT SURGERY
If the desired correction is not initially achieved by PRK laser surgery, we may wish to consider enhancement PRK surgery. This may involve adding complementary laser incisions, or augmenting those which have already been made. The timing of PRK enhancement surgery vary from case to case.
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