Eyeworld

EW FEATURE 34 February 2011 Keratorefractive enhancement of pseudophakes July 2014 daunting," he said. "PRK eliminates those potentials." Identifying the risk/ safety profile Regardless of refractive surgical experience, Dr. Hoffman cautions surgeons to be wary when correcting residual refractive errors, and added that some physicians advocate only a 6- to 8-week waiting period before performing LASIK. "For me, the ease of the PRK procedure makes this my go-to technique 90% of the time," he said. Dr. Stonecipher agreed, as the transepithelial approach is "easy and quick. The patients don't complain, and with the lower refractive error the outcomes are good." The so- called "transPRK" is considered an advanced version of surface treat- ments (LASEK, epi-LASIK, and PRK). In this technique, the epithelium is ablated by the laser without the eye coming into direct contact with any instrument. For cataract practices that have adopted the use of a femtosecond laser, Dr. Devgan said the transition to LASIK for enhancement surgery is fairly straightforward, "particularly if the practice has a femtosecond laser that does both cataract and corneal flaps." Choosing between PRK and LASIK is based on refraction and vi- sual rehabilitation, Dr. Stonecipher said. "That said, the laser astigmatic relaxing incision and LASIK patients heal instantly. However, the eco- nomics of these enhancements is a bit higher," he said. "In most in- stances my PRK enhancements can be done using an enhancement card on my VISX laser [Abbott Medical Optics], and the outcomes are similar to those of LASIK for this patient population." In order to properly use an ex- cimer laser, surgeons need to be cer- tified, Dr. Hoffman said, and need to be overseen for the first few cases. Additionally, some physicians use a trephine with alcohol to soften the epithelium, then "use a blunt blade to remove the epithe- lium all at once, which has a very short learning curve," Dr. Hoffman said. For surgeons who opt to use alcohol to facilitate the process, Dr. Hoffman recommends a 30-second exposure, but 40 seconds "for younger patients." Building confidence For those who need a hyperopic cor- rection, Dr. Hoffman recommends PRK. "You can correct for hyperopic outcomes with LASIK, but there's a greater chance the flap isn't as wide as you'd like it to be. With PRK, that's not an issue. Hyperopic corrections tend to need a 9 mm flap or larger, whereas myopic cor- rections only need 8.0–8.5 mm," he said. Centration of the flap is more of an issue when the correction is hyperopic, he added. "But if the surgeon is proficient with femtosecond laser for ad- vanced cataract surgery, all those learning curve issues are signifi- cantly diminished. For the non- corneal surgeon, however, PRK is truly a non-threatening, easier technique," Dr. Hoffman said. EW Editors' note: The physicians have no financial interests related to their comments. Contact information Devgan: devgan@gmail.com Hoffman: rshoffman@finemd.com Stonecipher: stonenc@aol.com Experts continued from page 33 One surgeon's pearls For the novice keratorefractive surgeon, Dr. Devgan suggests: When performing PRK in pseudophakes with residual refractive error: 1. Let the patient fully heal after the cataract surgery. This means waiting 2 to 3 months. 2. Ensure the tear film is healthy and there is no active dry eye issue. 3. Check topography to see that all is regular and symmetric (no epithelial basement membrane dystrophy, no irregularities, etc.). 4. Put the desired correction prescription into trial frames and have the patient try it around the office. In particular, be careful of patients who want you to make their far vision sharper by treating their residual myopia. They may not realize that they're using the residual myopia in order to see their cellphone. "If the patient is –1.00 or so, I may put a contact lens in the eye for a day so that they can see what the results of PRK would be," he said. For the PRK procedure itself, this is a simplified technique: 1. Use a small circular sponge soaked in alcohol on the cornea for 45 seconds. Then simply wipe off the epithelium with a dry Weck-Cel sponge. 2. Do the PRK treatment. You do not need large optical zones since these older patients have small pupils and your laser treatment is very low. 3. Mitomycin-C is not typically needed, but can be used if desired. 4. Place a bandage contact lens and use topical nonsteroidals until the corneal epithelium is healed/closed, then remove the contact lens and switch to low dose topical steroids for at least a month. Watch these videos on your smartphone or tablet using your QR code reader. (Scanner available for free at your app store.) Laser treatment of residual refractive error Laser removal of epithelium Source (all): Karl Stonecipher, MD clinical.ewreplay.org/?v=36 42407256001 clinical.ewreplay.org/?v=36 42392321001 Transepithelial PRK Alcohol-assisted PRK 30-37 Feature_EW July 2014-dl_Layout 1 6/30/14 8:42 AM Page 34

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