Eyeworld

EW RESIDENTS 46 November 2016 by James O'Brien, MD, Ilya Sluch, MD, Andrew Melson, MD, Joshua Hendrix, MD, Jason Smart, MD, Christina Lippe, MD, Vincent Venincasa, MD, Kyle Rogers, MD, Russell Burks, MD, Clifton Fay, MD, Andrew Rodenburg, MD, and Valerie Lobodiak, MD, Dean McGee Eye Institute residents S ince the first application of photorefractive keratecto- my (PRK) on human eyes in 1987 and laser in-situ keratomileusis (LASIK) in 1991, the field of refractive surgery has blended and modified the two procedures in order to combine the safety profile of PRK with the recov- ery time of LASIK. With the advent of more precise laser technologies, we are now able to offer transepi- thelial photorefractive keratectomy (transPRK), femtosecond-assisted LASIK (femtoLASIK), femtosecond lenticule extraction (FLEx), and small incision lenticule extraction (SMILE). TransPRK treatment pa- rameters account for the variance in epithelial ablation, and it delivers a single photoablation treatment to the cornea without the need for epithelial removal or flap creation. Meanwhile, the femtoLASIK plat- form utilizes a 1053 nm femtosec- ond laser to create a bladeless corne- al flap, followed by stromal ablation, which avoids the complications of a microkeratome. While all of these procedures have data supporting their safety and efficacy, few studies compare them head to head. This particular study compares 1-year postoperative refractive outcomes of transPRK versus femtoLASIK. Study summary This study was a retrospective, case- matched comparative series that evaluated the long-term postoper- ative visual outcomes of transPRK and femtoLASIK refractive surgery techniques. Ninety-eight patients (196 eyes) who underwent transPRK were compared to 196 case-matched eyes that underwent femtoLASIK. TransPRK patients were matched with femtoLASIK patients by calcu- lating the differential blur vector, a representation of the patients' spherical, cylindrical, and axis com- ponents of their refractive error. All patients had baseline examination including both uncorrected and cor- rected distance visual acuity, mani- fest refraction, corneal topography and pachymetry, pupillometry, slit lamp examination, and dilated fun- dus examination. On postoperative day 7, uncorrected and corrected distance visual acuity and manifest refraction were recorded, followed by 3- and 12-month postoperative Review of "1-year experience in myopia correction with transepithelial PRK case- matched with femtosecond-assisted LASIK" One-year experience in myopia correction with transepithelial PRK case-matched with femtosecond-assisted LASIK Michiel H.A. Luger, MD, Tobias Ewering, Dipl-Ing (FH), Samuel Arba-Mosquera, PhD J Cataract Refract Surg. 2016;42(11). Article in press Purpose: To compare the postoperative clinical outcomes of single step transepithelial PRK (transPRK) and femtosecond-assisted LASIK (femtoLASIK) treatments based on the efficacy and the safety of the procedure. Setting: Private practice. Design: Retrospective case-matched series. Methods: 98 patients (196 eyes) operated consecutively with transPRK were retrospectively compared to 196 case matched eyes (based on the preop refractive components) treated with femtoLASIK. For all eyes, aspheric treatments were planned and performed with the SCHWIND AMARIS 750S system (SCHWIND eye-tech-solutions). Clinical outcomes were evaluated in terms of predictability, refractive outcome, and visual acuity. Student's t-test and Chi square test were used for the statistical analysis. Results: For all patients, 1-year follow-up was completed. At 1-year, 66% (130 eyes) of the eyes in the transPRK and 46% (91 eyes) of the eyes in the femtoLASIK group achieved UDVA –0.1 logMAR or better (p<.005); 2% (4 eyes) of the eyes in the transPRK and 1% (2 eyes) of the eyes in the femtoLASIK group lost two lines of CDVA (p=.04); 83% (163 eyes) of the eyes in the transPRK and 85% (167 eyes) of the eyes in the femtoLASIK group were within ±0.50 D of emmetropia. Postoperative mean spherical equivalent was +0.11±0.56 D for transPRK and –0.09±0.46 D for femtoLASIK (p<.0001). Conclusions: In our cohort, transPRK outcomes at 1 year postoperatively were equivalent to the femtoLASIK outcomes. TransPRK procedures are efficacious and safe, although affected by longer recovery times compared to femtoLASIK. David W. Jackson, MD, Clinical associate professor, Dean McGee Eye Institute How does transepithelial PRK compare to femtosecond laser-assisted LASIK? I asked the Dean McGee (Oklahoma) residents to review this head- to-head study that appears in this month's issue of JCRS. –David F. Chang, MD, EyeWorld journal club editor examinations that included all of the components of the baseline as- sessment. The outcomes of primary interest were the postoperative visu- al acuity and refractive error. The procedures were performed by 11 different surgeons in Utrecht, Netherlands. Patient preference, surgeon preference, and corneal thickness were factors that deter- mined whether transPRK or femto LASIK was chosen for a patient. Patients were excluded if they were "systemically ill," or had postoper- ative residual stromal bed thickness less than 300 microns, preoperative corneal thickness less than 470 microns, or "abnormal" corneal topography. Retreatment cases were also excluded. Systemic illness and abnormal corneal topography were not further defined. continued on page 48 The average age of patients treated with transPRK was 36±11 years (range 18 to 79 years) and 39±10 years (range 20 to 62 years) for patients who underwent femto- LASIK (p<0.01). The two treatment groups had similar preoperative mean spherical refractive error (–3.36±1.78 D and –3.34±1.74 D for transPRK and femtoLASIK, respec- tively, p=0.2). There was a significant difference with astigmatic error (mean 1.10±0.91 D and 1.00±0.84 D for transPRK and femtoLASIK, respectively, p<0.0001), with corre- sponding difference in mean topog- raphy between groups (43.82±1.47 D and 43.47±1.38 D for transPRK and femtoLASIK, respectively, p<0.01). Both groups were similar with

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