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A.P. Urbano, R. Nosé, W. Nosé; Analysis of Zyoptix and Planoscan Treatment Data . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2675.
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Purpose: To compare the ablation data of Zyoptix and Planoscan treatment in eyes submitted to wavefront-guided ablation. Methods: This cross-sectional study comprised 69 eyes of 49 patients submitted to customized ablation with Chiron Technolas 217-Z Excimer Laser. Of the studied eyes, 53.6% had never been submitted to any refractive procedure (normal eyes) and 46.4% had previous refractive surgeries (abnormal eyes). Preoperative examination included ultrassound pachymetry, corneal tomography with Orbscan II and wavefront analysis with Zywave (Shack-Hartmann aberrometer). Zyoptix treatment was calculated using Zylink program. The same refraction and optical zone data was considered for Planoscan treatment calculation for each eye. Data related to maximum ablation depth, number of pulses, presumed post-operative pachymetry and presumed posterior stromal bed thickness were evaluated. Pre-operative ultrassound and orbscan pachymetry were also compared.Results: The mean preoperative spherical refraction was - 1.85 diopters (D) +/- 1.38 (SD) and the cylinder was - 1.13 +/- 1.00 D. Mean optical zone was 6.02 +/- 0.27µ. There was no statistical difference in maximum ablation depth between Zyoptix treatment ( 54.61 +/- 24.65 µ) and Planoscan treatment ( 54.25 +/- 31.09 µ). (p=0.94). Presumed post-operative pachymetry was equivalent for Zyoptix treatment (464.74 +/- 46.16 µ) and Planoscan treatment ( 465.10 +/- 43.80 µ). (p=0.96). Presumed residual posterior stromal bed thickness was 308.65 +/- 43.03 µ for Zyoptix treatment and 309.01 +/- 40.39 µ for Planoscan treatment. (p=0.95). Regarding to the number of pulses, Zyoptix required a mean of 2.718 +/- 1.049 pulses while Planoscan would use 1.554 +/- 875 pulses (p=0.01). Similar results were obtained when the analysis was performed for each group (normal eyes and abnormal eyes). Ultrassound and Orbscan pachymetry were correlated in the analysis of normal eyes (Pearson coefficient = 0.717; p= 0.001) as well as abnormal eyes (Pearson coefficient= 0.769; p=0.01) Conclusions: Zyoptix treatment is comparable to Planoscan treatment regarding to maximum ablation depth, presumed post-operative pachymetry and posterior stromal bed thickness when the same refraction and optical zone are taking into account.
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