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Purpose: The aim of the study was to determine and compare the relationship between change in simulated keratometry (K) and degree of refractive correction in wavefront-guided (WFG) and wavefront-optimized (WFO) myopic laser-assisted in situ keratomileusis (LASIK). Methods: A total of 51 patients were prospectively randomized to WFG LASIK in one eye and WFO LASIK in the contralateral eye at the Byers Eye Institute, Stanford University. Changes in simulated K and refractive error were determined at 1 year post-operatively. Linear regression was employed to calculate the slope of change in simulated K (ΔK) for change in refractive error (ΔSE). The mean ratio (ΔK/ΔSE) was also calculated. Results: The ratio of ΔK to ΔSE was larger for WFG LASIK compared to WFO LASIK when comparing the slope (ΔK/ΔSE) as determined by linear regression (0.85 vs 0.83, p = 0.04). Upon comparing the mean ratio (ΔK/ΔSE), subgroup analysis revealed that ΔK/ΔSE was larger for WFG LASIK for refractive corrections of >3.00 D and >4.00 D (0.89 vs 0.83; p = 0.0323 and 0.88 vs 0.83; p = 0.0466, respectively). Both linear regression and direct comparison of the mean ratio (ΔK/ΔSE) for refractive corrections <4.00 D and >4.00 D revealed no difference in ΔK/ΔSE between smaller and larger refractive corrections. Conclusion: WFO LASIK requires a smaller amount of corneal flattening compared to WFG LASIK for a given degree of refractive correction. For both, there was no significant difference in change in corneal curvature for a given degree of refractive error between smaller and larger corrections. [ABSTRACT FROM AUTHOR]

Aim: The aim of the present study was to compare the differences in visual outcomes, higherorder aberrations and corneal asphericity, as measured by Q values, in patients undergoing laser in-situ keratomileusis using wavefront-guided variable-spot size VISX CustomVue and wavefront-optimized small-spot size WaveLight Allegretto platforms. Type of study: This study was designed as a randomized, prospective, single-blinded, double-armed, felloweye comparative study. Patients and methods: A total of 100 eyes of 50 patients undergoing customized laser in-situ keratomileusis for compound myopic astigmatism were enrolled and randomly divided into two groups. Each patient underwent full ophthalmological examination; aberrometry was performed on either eye by using VISX CustomVue aberrometer and Allegretto WaveLight aberrometer. Each patient had one eye examined using the Allegretto Wave eye Q system (small-spot scanning), and the fellow eye by using VISX Star CustomVue S4 system (variable-spot scanning). All patients were given postoperative steroids, antibiotic drops and artificial tears. First day postoperative visit was scheduled to check for fl ap stability, and to exclude complications. Clinical examination and best corrected visual acuity, corneal imaging and aberrometry were scheduled at 1 month and 1 year later. Results: Final best corrected visual acuity showed insignificant difference between the two groups (P = 0.712). The fi nal differences between the groups were insignificant in all other parameters. Conclusion: The two ablation profiles are highly comparable in treating compound myopic astigmatism. [ABSTRACT FROM AUTHOR]