Abstract
Background:Corneal refractive surgery for myopia results in an oblate shift with increased postoperative aberrations inversely affecting the quality of vision.Aspheric ablation profiles have been introduced to minimize such a prob-lem.The aim of this study was to compare changes in corneal asphericity,central and mid-peripheral pachymetry between the Q-value customized and the wavefront-optimized(WFO)ablation profiles.Methods:A prospective,comparative non-randomized fellow eye study was conducted.Eighty eyes of 40 eligible patients underwent femtosecond laser-assisted laser in situ keratomileusis for myopia and myopic astigmatism.In each patient,the more myopic eye was included in the custom-Q ablation experimental group and the other less myopic eye was included in the WFO control group.For the custom-Q group,the target asphericity was set to the preoperative Q-value.Corneal asphericity,central and mid-peripheral pachymetric changes and the root mean square of corneal higher-order aberrations(RMSh)were assessed 6 months following surgery.Visual and refractive outcomes were also evaluated in both platforms 6 months postoperatively.Results:The mean preoperative refractive spherical equivalent was significantly more myopic in the custom-Q group than in the WFO group(P=0.001).The mean Q-value changed from-0.2±0.1 to 0.6±0.7 and from-0.2±0.1 to 0.4±0.5 in the custom-Q and WFO groups,respectively.The oblate shift in corneal asphericity was not significantly different between both treatment groups(P=0.094).The mean ablation depth at the pupillary center was signifi-cantly greater in the custom-Q group(P=0.011),while there was no significant difference at the mid-peripheral pachymetry(P=0.256).The RMSh significantly increased in both treatment profiles(P＜0.001)with no significant dif-ference between the two groups(P=0.06).The uncorrected distance visual acuity(UDVA)and the manifest refraction spherical equivalents(MRSE)significantly improved in both treatment groups(P＜0.001).Conclusions:The custom-Q treatment profile with target asphericity set at the preoperative Q-value achieved com-parable outcomes vs.the WFO profile in terms of postoperative corneal asphericity and mid-peripheral pachymetry despite the greater amount of ablation,the smaller optical zone,and the resulting increase in postoperative corneal flattening in the custom-Q group.
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