Abstract
The goal of this study was to compare differences in the mean angle kappa and its intercepts before and after photorefractive keratectomy (PRK) for myopia. In a prospective controlled study, myopic patients were treated with aspheric wavefront-guided (personalized) PRK with a Bausch & Lomb Technolas 217z excimer laser. The manifest refraction, visual acuity, and angle kappa were evaluated preoperatively and at 1 and 6 months postoperatively. The same operator performed all angle kappa measurements using Orbscan IIz. A total of 48 cases (96 eyes, 68.75 % female) with a mean age of 26.70 ± 4.89 years (18–34 years) were treated. The preoperative and postoperative mean angle kappa values were not significantly different (4.97 ± 1.24 vs 4.99 ± 1.10 at 6 months). The average horizontal distance (x-intercept) between the visual axis and pupillary axis intersection on the corneal surface measured before surgery (−0.562 ± 0.074 mm) did not significantly differ from the values measured at 1 and 6 months after surgery (−0.559 ± 0.048 and −0.554 ± 0.055 mm, respectively). Similarly, the average vertical distance (y-intercept) values did not differ before and at 1 and 6 months after surgery (0.156 ± 0.225, 0.142 ± 0.040, and 0.149 ± 0.33 mm, respectively). No differences in the angle kappa or its corneal intercepts were observed between pre- and post-PRK. This finding implies that PRK does not change the corneal vertex locations.
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Acknowledgments
The authors would like to thank Pardis Eghbali BSc for her help in Orbscans measurements, Maryam Kadkhoda BSc and Jalil Rahimi BS for their help in optometric tests, Parisa Eghbali MSc for her assistance in statistical analysis. This work was part of ophthalmology specialty thesis of Dr Mojtaba Abrishami and was supported by research Grant No. 88708 from office of Vice-Chancellor for Research Affairs of Mashhad University of Medical Sciences.
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Zarei-Ghanavati, S., Gharaee, H., Eslampour, A. et al. Angle kappa changes after photorefractive keratectomy for myopia. Int Ophthalmol 34, 15–18 (2014). https://doi.org/10.1007/s10792-013-9775-x
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DOI: https://doi.org/10.1007/s10792-013-9775-x