Visual quality of patients with myopia after sub-Bowman's keratomileusis

Objective To investigate the contrast sensitivity and higher order aberrations of patients with myopic astigmatism after sub-Bowman's keratomileusis(SBK).Methods With randomly control clinical study,patients with myopic astigmatism,who were performed with laser treatment,were divided into 2 groups.About 71 cases(71 eyes)were taking SBK in group A,67 cases(67 eyes)taking traditional LASIK in group B.Only right eyes were analyzed.The results were compared.Higher order aberrations,contrast sensitivity and questionnaire of objective satisfaction were detected before and after operation.The patients were followed up at postoperative 1 week,1 month,3 months,6 months and 12 months.Results There was no difference in each index between the two groups at pre-operation(all P0.05).At postoperative 12 months,average higher order aberrations were(0.416±0.067)μm in SBK group and(0.614±0.098)μm in LASIK group,there was statistical difference(t=-13.922,P=0.001).Contrast sensitivity achieved the preoperative level at postoperative 3 months to 6 months in SBK group and at postoperative 6 months to 12 months in LASIK group.At postoperative 12 months,contrast sensitivities under photopic and mesopic circumstances in SBK group were better than those in LASIK group at different spatial frequencies,there were differences under photopic circumstance at low and medium spatial frequencies or under mesopic circumstance at low,medium and high spatial frequencies.The objective satisfactory rates were 95.8% in SBK group and 89.6% in LASIK group.Conclusions Comparing with conventional LASIK,SBK achieves a lower induced HOA,faster recovery of contrast sensitivity at low,medium and high spatial frequencies and a higher satisfaction of patients.