Inclusion Criteria:  age over 18 years corrected distance visual acuity (CDVA) in logarithm of minimal angle of resolution (LogMAR) of 0.10 or better refractive error stabilized for at least 1 year discontinued contact lens use for at least 2 weeks  Exclusion Criteria:  presence of corneal scars keratoconus glaucoma retinal diseases a history of corneal or intraocular surgery