Eyeworld

63 EW REFRACTIVE SURGERY June 2016 try to lift it and 1 of the incisions is filleted open," Dr. Rush said. However, he has experimented with many different femtosecond laser settings, trying to modulate the way it cuts the flap. "Through our experience, we are aware of settings where we can cut a femtosecond flap and leave no tissue bridges behind—where it cuts completely clean all of the way through," Dr. by Maxine Lipner EyeWorld Senior Contributing Writer appears to be an 8-slice pizza pie-like flap, Dr. Rush said. There is also concern about evacuation of the air bubbles left by the femtosecond laser, with the worry that in certain circumstances there may be verti- cal gas breakthrough via an old RK incision. "You open a whole can of worms for potential complications with epithelial ingrowth or an un- stable flap or irregularity when you said. "We like the flexibility it gives us with controlling the flap depth and the diameter." The problem in RK patients is that the femtosecond flap doesn't just lift open; it leaves little stromal bridges that have to be broken apart by an instrument, he explained, adding that in the RK patient, the prior incisions can sometimes be more fragile than the perforated edge left by the femto- second laser. The result can be what Study results indicate there is no need to forego femtosecond LASIK in such patients A prior radial keratotomy (RK) usually makes practi- tioners think twice about creating a LASIK flap with a femtosecond laser. But study results published in the September/October 2015 issue of the Asia-Pacific Journal of Ophthalmology point to the fact that the femtosec- ond laser can be a viable option, according to Sloan Rush, MD, in private practice, Amarillo, Texas. The results indicated that LASIK flaps were able to be successfully created in 100% of the post-RK patients who were included here, he reported. The investigation was spurred by the fact that many of the patients who underwent RK in the late 1980s and 1990s are now in a situation ripe for retreatment. "As we know, many of our RK patients develop hyperopic regression, so they come back to us years later. Some of them are now in their late 40s and others in their early 50s," Dr. Rush said. Such individuals are seeking addi- tional refractive treatment because they are now becoming presbyopic and the hyperopic refraction with which they are living has become problematic. While they may have been able to accommodate through this in the past, with the beginning of presbyopia, that is no longer pos- sible, and they want something else done, he explained. "Ideally, we don't want to offer them a refractive lensectomy, especially if there is no cataract there," Dr. Rush said. "In my center we prefer not to do PRK because we know in our hands we're better with LASIK, and PRK can have healing problems and take longer to recov- er from." Dr. Rush's top choice is LASIK, assuming that he can create a safe and successful flap. Femtosecond RK dilemmas While traditionally a manual microkeratome has been success- fully used, some practitioners have moved away from these. "Now a lot of us—myself included—have hung the microkeratome on the shelf, and we feel a lot more comfortable using the femtosecond laser," Dr. Rush Femtosecond laser flap creation in prior RK patients Some practitioners are hesitant to create a LASIK flap with a femtosecond laser in prior RK patients. Source: John Berdahl, MD continued on page 64 A recent study found that femtosecond LASIK can be a viable option for prior RK patients. Source: Uday Devgan, MD

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