Clinical investigation on contrast sensitivity and higher order aberration after Q-factor guided SBK and LASIK for myopia

Objective To investigate the contrast sensitivity and higher order aberrations of myopic after Q-factor guided Sub-Bowman's Keratomileusis (SBK) and Laser In Situ Keratomileusis (LASIK).Methods With non-randomly control clinical study,patients with myopic astigmatism who wcre divided into 2 groups from January 2012 to June 2012 after Q-factor guided laser treatment.Of 36 cases (72 eyes) were taking SBK in group A,28 cases (56 eyes) taking LASIK in group B.Higher order aberrations and contrast sensitivity in dark environment without glare were detected before and after operation,and the results were compared.The patients were followed up at postoperative 1 month,3,6 and 12 months.Results There was no difference in each index between the two groups at pre-operation (all P ＞0.05).The contrast sensitivity of SBK group returned to the preoperative level after 3-6 months,and the LASIK group retumed to the preoperative level after 6-12 months.However,contrast sensitivity of every space frequency in SBK group were better than those in LASIK group at 12 months after surgery,the low and medium frequency were more significant.At postoperative 12 months,average higher order aberrations were (0.476±0.137) μm in SBK group and (0.83±0.154) μm in LASIK group,there was statistical difference (P =0.001).Conclusions Under Q-factor guided treatment,comparing with LASIK,SBK achieves a lower induced HOA,faster recovery of contrast sensitivity at low,medium and high spatial frequencies. Key words: Sub-Bowman's Keratomileusis;  Laser In Situ Keratomileusis;  Contrast sensitivity; Higher order aberration