Inclusion Criteria:  age between 20 and 50 years old CDVA of both eyes could reach 0.1 logarithm of the minimum angle of resolution (logMAR) stable refractive errors of myopia and astigmatism  Exclusion Criteria:  cataract corneal opacities or irregularities dry eye (Schirmer's test I ≤ 5mm) amblyopia coexisting ocular pathologies glaucoma non-dilating pupil history of intraocular surgery, laser therapy, or retinopathy optic nerve or macular diseases estimated postoperative cornea residual stromal thickness less than 250 μm pregnancy or under lactation uncontrolled diabetic mellitus or systemic immune disease refusal or unable to maintain follow-up