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Julie Colne, Cedric Ghetemme, Jean-Marc Perone; Efficiency, predictability and security of the trans-epithelial photorefractive keratectomy (trans-PRK) for low and medium myopia and astigmatism: retrospective study about 118 eyes. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4869.
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© ARVO (1962-2015); The Authors (2016-present)
The photorefractive keratectomy was the first correction mode refractive laser. It’s a photo-ablation of a predetermined thickness of anterior corneal stroma. Debridement of epithelium can be done either mechanically (m-PRK) or by laser (trans-PRK). Trans-PRK has a lot of interests: facility and speed of procedure as well as suppression of human variable. Very good results are obtained by m-PRK. The aim of this study is to show equivalence or non inferiority of trans-PRK over conventional m-PRK in terms of safety and refractive efficiency.
This is a retrospective, observational and monocentric study including 62 patients and 118 eyes. Were included myopia up to -4D (dioptries) and cylinders up to -3D. The ametropia was stable for 2 years. Careful refraction was made. All trans-PKR were made on the schwind amaris 500E platform. Epithelium ablation profile was 55µm in the center against 65 µm in the periphery. The optical central zone was equal to 6,5 mm. Young patients (under 35 years) had a + 0,25 D target refraction, for the older, the not leader eye was left intentionally myopic (between -0,50 and -2D) and the others had for refractive target 0D.The visual target acuity in log MAR was 0. The postoperative treatment consisted of rimexolone eye drops and final refractive control was made at two months.
Of the 118 eyes operated, 51 presented myopia, 9 astigmatism and 58 myopia and astigmatism. Postoperatively, 5 eyes had uncorrected VA less effective than the preoperative best corrected visual acuity (BCVA). 113 eyes had their target visual acuity (0 log MAR or visual acuity equivalent of their BVCA). The residual average refractive disorder was calculated in spherical equivalent: it was equivalent to 0,318 +/-0,028 D (myopia: 0,27 +/- 0,180D, astigmatism : 0,498 +/- 0,337D, myopia-astigmatism :0,333+/- 0,234D) . No eye had a refractive disorder superior to 1D.
In any confused ametropia, the residual average refractive disorder was equal to 0, 31 D. Result was lower when only myopia was corrected (0,27D) and more important when considering cylinder correction (0,498D). The trans-PKR procedure appears as a simple, fast, uniform, secure and reproducible procedure, with excellent refractive final results, comparable and not lower than those obtained after m-PRK.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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