| ObjectiveTo elucidate factors which correlate with changes of higher order aberrations (HOA) after refractive surgery; to compare higher order aberrations and their changes after surface and stromal ablation surgeries; to evaluate relationship between subjective visual perception and objective results of visual quality related examinations, in order to provide further evidence for surgery selection and customized ablation.Methods1. This prospective study included 116 eyes of 61 patients who seek for refractive surgery in our hospital from Aug 2007 to Feb 2008: average age (28±6); 84 eyes of 45 patients received laser in situ keratomileusis (LASIK) and 32 eyes of 16 patients received advanced surface ablation (ASA), among which 8 eyes of 4 patients received laser subepithelial keratomileusis (LASEK) and 24 eyes of 12 patients received epipolis laser in situ keratomileusis (EPI-LASIK). Spherical equivalent (SE) of LASIK group ranged from -1.25 to -8.75 D, average (-5.85±1.77) D, SE of ASA group -2～-9.25 D, average (-5.38±1.83) D.2. Record uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BSCVA), spherical and cylindrical diopter, SE, and wavefront aberrations of patients before and 1, 3, 6 months after ablation. Calculate wavefront aberration with WaveLight Allegretto aberrometry under identical conditions, and record RMSh, RMS3～RMS6, and C3～C14, i.e. Z-2/2～Z4/4 with pupil diameter of 6mm.3. Obtain general evaluation, comparisons of pre- and post-operation visual quality and symptoms by the same clinician 1, 3,6 months after ablative surgery.Results1. Preoperatively, refraction correlated significantly with higher order aberration, especially spherical aberration, coma and trefoil: spherical diopter correlated with C7, C9, C12, and C1, cylindrical diopter with C6, C7, C9, C11, C13, and C14, and SE with C9 and C12. Cylindrical diopter positively correlated with RMS3～6 and RMSh; spherical diopter has no correlation with HOA.2. Changes of C7, C12, RMS3～6 and RMSh positively correlated with changes of spherical, cylindrical diopter and SE. Changes of C4 and C5 (90 degree astigmatism) positively correlated with changes of refraction; C3 (45 degree astigmatism) has no correlation with changes of refraction.3. C7, RMS3, RMS6, and RMSh of ASA group was significantly smaller than that of LASIK group 1 month after surgery; C7 and C14 of ASA was smaller than LASIK 3 month after surgery, while C12 of LASIK smaller than ASA; only C14 of ASA was smaller than LASIK 6 month after surgery.4. Changes of RMS3, RMS5, RMS6, and RMSh of ASA group was significantly smaller than that of LASIK group 1 month after surgery; Changes of RMS6 of ASA was smaller than that of LASIK 3 month after surgery; Changes of RMS3, RMS6, and RMSh of ASA was smaller than that of LASIK 6 month after surgery.5. Compared with best spectacle corrected vision preoperatively, diurnal sight vision improved in most patients, while glare and worse nocturnal was complained by most patients. Early postoperative changes of SE and spherical diopter negatively correlated with nocturnal driving, glare, nocturnal vision scales. Nocturnal symptoms improved with follow-up.6. Symptoms of glare positively correlated with postoperative coma, spherical aberration, and HOA.7. Early postoperative scales of driving, diurnal sight vision, nocturnal vision, glare and general vision were higher in LASIK group than in ASA, while symptoms of two groups had no significant difference. Scales between groups 6 month after surgery had no significant difference.Conclusions1. Lower order aberrations and higher order aberrations correlated with each other, and cylindrical diopter was positively correlated with HOA.2. Increase of HOA positively correlated with changes of SE and spherical diopter.3. Both HOA and its increase of ASA group were smaller than that of LASIK.4. Larger early postoperative changes of SE, spherical diopter, and HOA correlated with worse nocturnal visual quality and glare.5. Early postoperative visual quality scales of ASA were lower than that of LASIK.
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