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J. E. Ellis, C. Reilly, V. Panday; High Order Aberrations After Standard versus Custom Wavefront-Guided PRK. Invest. Ophthalmol. Vis. Sci. 2008;49(13):2899.
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© ARVO (1962-2015); The Authors (2016-present)
To compare root mean square high order aberration (RMS HOA) before and after treatment among active duty military who underwent standard (STD) vs. wavefront guided (WFG) PRK with either the VISX S4 (S4) or LADAR 4000/6000 (LADAR) laser platforms.
After IRB approval was obtained, a retrospective analysis was performed of the Warfighter Refractive Surgery Database that identified 201 eyes meeting inclusion criteria. Inclusion criteria were patients who received STD or WFG PRK at the Warfighter Refractive Surgery Center with the S4 or LADAR platforms for myopia between Jan 1996 and Nov 2006; returned for at least one follow up visit; and had a wavescan performed on the CustomVue or LADARVision wavescanner both preoperatively and postoperatively. Main outcome measures were RMS HOA, contrast sensitivity (CS), best corrected visual acuity (BCVA), and manifest refractive spherical equivalent (MRSE). Right vs. left eyes were also compared in this study to evaluate for postoperative differences in RMS HOA.
In the S4 group, RMS HOA increased postoperatively 32% with STD and 27% with WFG ablation (p 0.07). CS was similar with STD vs. WFG ablation (35 + 15 vs. 36 + 10) as was BCVA (20/17 vs. 20/15). Postoperative MRSE was slightly larger in the STD group (+0.07 D vs. -0.03 D). The LADAR group showed RMS HOA increase of 28% with STD and 49% with WFG ablation (p 0.14). Postoperative CS was worse with STD (45 + 5 vs. 35 + 10), but BCVA was not affected (20/15). MRSE was greater with WFG (+0.26 D vs. +0.04 D). These results were not statistically significant. In addition, no statistically significant difference was noted in right vs. left eyes in terms of RMS HOA (33% increase vs. 26%) (p 0.33) or CS (36.0 + 11 vs. 35.5 + 10).
There is a slight tendency for worsening of RMS HOA with STD ablation with S4 and WFG ablation with LADAR as well as a tendency for overcorrection with WFG ablation with LADAR. This likely represents surgeon familiarity with the S4 platform as the LADAR is a new laser to our refractive surgery center. In the military setting where emphasis is more on treating large numbers of patients in preparation for deployment to environments where spectacles or contact lenses are not practical, this study shows no statistical difference between STD vs. WFG ablation to warrant the added cost and evaluation time needed to perform WFG ablations. Military refractive surgery centers could adopt a policy of performing only standard ablation on the majority of patients and utilizing WFG ablations in those with symptomatic residual HOA at a center that has WFG ablation capabilities. There was no statistically significant difference in right vs. left treated eyes.
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