Objective To analyze the formation of anterior chamber bubbles during corneal flap creation in myopic patients who underwent laser-in-situ keratomilusis (LASIK) using the lntraLase femtosecond laser.Methods It was a restrospective case control study.One thousand thirty-four patients (2057 eyes) who underwent LASIK using the IntraLase femtosccond laser were enrolled in this study.Anterior chamber gas bubbles were noted in study group (51 eyes) with no anterior chamber gas bubbles in the other 2007 eyes (control group).The causes of anterior chamber buble formation were analyzed.The date were analyzed by independent samples t test.Results Flap creation was successful and myopic ablation was uneventful.The conneal diameter in the study group was smaller than that in the control group (t=-9.21,P＜0.05),but there were no significant differences between the two groups in other corneal parameters.Conclusion With a larger pupil and precise tracking,anterior chamber bubbles has no effect on postoperative visual acuity.To avoid the formation of anterior chamber bubbles during corneal flap creation,we would tighten the flap diameter in smaller corneas.