|
|
|
Confused About RK—PRK—LASIK
to Correct Cataract
Surgery Contact
Us
|
Confused
About RK—PRK—LASIK to Correct If you’re confused about whether to have RK surgery or excimer laser surgery for the correction of myopia (nearsightedness) you’re not alone. A tremendous amount of money and time has been spent by advertising agencies to present an appealing "product" for you to purchase! The problem is, this isn’t just any product, it's your eyes. Yes, your eyes, and these are the only ones you’re going to get for the rest of your life! So what is the answer? Simple! Don’t believe anyone’s commercials or ads. Use the ads to identify people doing the surgery, and then investigate, investigate, investigate this product like you would any other product! To do that, you need to educate yourself on the facts not the hype. The" proven" scientific facts about all the procedures. Then, you investigate the credentials not the commercials of the surgeon you want to do the surgery. In the rest of this site, I’ll try to help you do both!
Radial Keratotomy This procedure is not really new! A Japanese doctor by the name of Sato, began it in the 1950's. Many successful cases were performed, but because of poor techniques, most cases eventually ended with a total loss of vision and the procedure was abandoned. In the late 1970’s the procedure was revived in Russia, with improvements in technique, and later brought to the United States with even further refinements. Because of the lack of knowledge about the safety and the results of this technique, a large multicenter study was established called the "Perk" study at many University's around the country. The surgery was performed by well trained surgeons all using the same equipment and techniques. The basic technique consisted of making 8 incisions in "spokewheel" fashion in the cornea, the front surface of the eye. The incisions were made by hand with very sharp diamond knives. The incisions were made very deep to 95% of the depth of the cornea. The data was collected and reviewed at 1, 3, 5, and recently 10 years. The results have been published and are controversial. The basic findings for each of the intervals published were basically the same. Only the percentages of success, failure, and complications changed. The statistics are based on reduction in nearsightedness to useful levels, which is considered to be 20/40 vision. This is the legal level for driving without glasses in all 50 states. At 10 years after RK, results for low nearsightedness between 2 and 3 units, showed 92% were 20/40 or better. For middle nearsightedness between 3 and 4.5 units, 86% were 20/40 or better. For high nearsightedness between 4.5 and 8 units, 77% were 20/40 or better. Twenty percent of cases needed second or third surgeries, referred to as enhancements. The results don’t sound too bad. But what about the problems and complications? I find, as a physician, that most people ask the wrong questions about surgeries! People always ask about the success rates, which are important, but I want to know what the failure rate is and what problems comprise the failure rate! If I told you that an eye surgery procedure has a 98% success rate you would think that's really great! But, what if the 2% failure rate was total loss of vision! This is not the case, of course, for any of these procedures, but if you don’t ask the question, you can’t know the answer! Most of the complications of radial Keratotomy are fairly low in incidence and include things we would expect in any eye surgery such as scarring, misplaced incisions, blurred vision, starburst effect, ineffectiveness of the surgery, perforation of the cornea, and infection. These complications have been shown to be fairly rare, but there is no way to predict who will have these problems. The major and most controversial finding, however, and the biggest long term problem for radial Keratotomy is the finding that 43% of RK patients had unstable, variable vision for at least 10 years after surgery! Many showed what is called progressive hyperopia, which means that the vision slowly progressed from "corrected" nearsightedness to farsightedness over time, leading to the need for glasses! This finding also put the success rate statistics into doubt, since perfect results at one year could be poor results at year 5 or 10! Critics of the Perk Study and its result point out that further refinement in the surgery and techniques, which were not included in the Perk Study, may show different results. This may be true; however, no long-term studies (8-10 yr.) are available for the newer vs. the older RK procedure. EXCIMER LASER (PRK) Now, we’ll do a similar analysis of Excimer Laser (PRK) correction of nearsightedness. This procedure has been approved in almost every country in the world and over 400,000 procedures have been performed worldwide. After extensive study, the FDA has now approved it in the U.S. The procedure itself is quite different from radial keratotomy, though the final intent, to reduce nearsightedness, is the same. Unlike radial keratotomy, the Excimer laser procedure is performed by a highly sophisticated, computerized laser, rather than by hand. In addition, the Excimer procedure is a "direct" method, whereas the RK procedure is an "indirect" method. The basic way both procedures correct nearsightedness is by flattening the cornea. RK does this indirectly by making incisions in the cornea, which cause weakening of the cornea and secondary flattening. This weakening is what causes the variable vision and the hyperopic shift, as well! The Excimer laser, on the other hand, vaporizes superficial layers of the cornea to "directly" flatten it the amount needed to correct your level of nearsightedness. It’s more like peeling the top five sheets of paper off of a pad of paper. Since there are no deep cuts in the cornea, as in RK, there is no weakening of the cornea, and almost no variable vision. Using the same criterion of 20/40 or better vision, as we did for RK, the success rates for the Excimer Laser Procedure in studies by Kim, Seiler, and Tengroth in three different countries were 91-92% in the low group, 92% in the middle group and 91% in the high group. The U.S. FDA studies were even more impressive with over 95% of patients seeing 20/40 or better after a single Excimer laser procedure. Complications consisted of slightly more pain than RK in the first 24 hours and mild starburst effect at night with headlights. Studies on satisfaction rates for the two procedures have also been performed by Gimbel et al. They found that 98% of patients were happy with Excimer results compared to 84% with RK. They also found that 90% of Excimer patients wore no corrective lenses compared to 60% with RK. Based on the above results it would appear that the major differences in the two procedures are the higher success rates in the Excimer studies, especially in the middle and high groups, and the variable, progressive vision changes that occur with RK and do not seem to occur with the Excimer Laser. Laser In Situ Keratomileusis (LASIK) LASIK surgery is the newest entry into the field of surgical correction of nearsightedness. This procedure combines the advances of laser surgery with a lamellar Keratectomy. The Keratectomy is performed using a hand held keratome with an oscillating blade to make a horizontal cut through the cornea. This creates a flap of tissue that can be elevated. This portion of the procedure is somewhat like a carpenter's wood plane moving across a piece of wood with a thin shaving of wood being elevated or like splitting a layer cake into two parts. After the tissue flap is lifted, the Laser procedure is performed exactly as for the PRK procedure. The flap is then gently placed back in its original position, covering the laser treated area. The flap usually seals tight in minutes without the use of sutures! The procedure takes about 15 minutes. The advantages of this procedure are: 1) It has a faster visual recovery than PRK (usually 1 or 2 days) 2) It has significantly less pain in the first 24 -48 hours 3) It can be used for higher levels of nearsightedness, -outside the range of standard PRK The disadvantages of the procedure are: 1) It is a technically more difficult procedure for the surgeon 2) It re-introduces hand held and mechanical variables to the procedure which were eliminated with the laser only procedure 3) There is a slightly higher risk of complications , in general This, procedure is not FDA approved in the U.S., as yet, despite its strong popularity around the world. Both the FDA and CRS, a private foundation, are presently running formal study's on the Lasik procedure to determine its safety and effectiveness and most refractive surgeons in the U.S. are, in fact, performing this procedure. Dr. Davidson is performing this procedure on appropriate candidates who want to have this procedure rather than PRK or who are not candidates for the standard PRK procedure. Picking a Surgeon Now you have to decide on whom you want to do your surgery! How do you choose! Well, the one thing you don’t do is listen to ads and commercials. We’ve all been bitten by slick advertising agencies promoting goods that don’t stand up to the ads. Medical advertising is no different. Agencies are paid to make the procedures and the surgeons look good. By educating yourself on the procedure, as we have done at this site you’re half way there! Now, you must educate yourself on your intended surgeon. If you don’t want to do the "homework" yourself, you can cheat a little by using certifications of the recognized national societies such as the American MedicalAssociation and the American Board of Ophthalmology. If your surgeon is Board Certified, he has been trained, tested and certified. If he is fellowship trained in Corneal surgery, he has additional extensive training in all types of corneal surgery. If your surgeon has these qualifications and you like and trust him, you’re set. If your surgeon does not have these certifications, then you must find out for yourself what his qualifications are! Ask for specific training documents! Ask for a Curriculum vitae which shows all training since medical school! Ask how much experience he has with corneal surgeries and more important complications of corneal surgeries! After all, refractive surgery for nearsightedness and farsightedness is-ssss corneal surgery. Doing a thousand cataract surgeries or RK’s doesn't necessarily make a good Excimer Laser PRK surgeon or LASIK surgeon! The only way you’re going to know is if you ask! Well, I’ve helped out as much as I can. If you educate yourself on the procedure and your surgeon, you will have done all you possibly can do to assure yourself of the best outcome possible for you.
|
|
Send mail to doctor@seeclearagain.com
|
