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Ryan P. Molchan, Vasudha Panday, Matthew Caldwell; Retrospective analysis comparing the pre and post operative "Q" Values for the Allegretto and Visix laser in refractive surgery. Invest. Ophthalmol. Vis. Sci. 2012;53(14):1496.
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Purpose: Higher order aberrations can limit a patient’s functional vision and overall satisfaction with refractive surgery. One measurement of induced aberrations is the change in corneal asphericity or Q value. Our study is designed to compare the pre and post-operative Q values following laser refractive surgery on both the Allegreto Wavefront Optimized and Visx Wavefront Guided laser platforms.
Methods: A retrospective database analysis of the Joint Warfighter Refractive Surgery center at Wilford Hall Medical Center was conducted to assess the change in corneal asphericity following laser refractive surgery. Study subjects included all patients who underwent PRK or LASIK surgery from 1 July 2010 to 15 December 2010 at WHMC. Data collection accomplished through preoperative assessments, surgical notes and post-operative visits. Data used for statistical analysis included pre and post Q values from the Pentacam, type of refractive treatment and the laser platform used.
Results: The average pre-operative Q value was -0.317± 0.29 for the VISX platform and -0.314 ±0.25 for the Allegretto. Postoperatively the change in asphericity was +0.22 ± 0.29 with the VISX platform with an average change of 0.141± 0.04 change in Q per treatment diopter while the average post op Q value was +0.08± 0.25 with an average change per diopter of treatment of 0.116± 0.041 (p<0.004.) There was no statistically significant difference in best corrected visual or contrast sensitivity between the two platforms.
Conclusions: Myopic correction with the Allegretto Wavefront Optimized laser was associated with a smaller change in the Q value per diopter of treatment when compared with the Visx Wavefront Guided laser. There was no statistically different outcome between the two platforms in post-operative best corrected or low contrast visual acuity.
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