Performance and Acceptability of iDesign

Inclusion Criteria: * Male or female, of any race, and at least 18 years old at the time the consent form is signed. * The refractive error, based on manifest refraction (adjusted for optical infinity), must be MRSE up to -15.00 D with manifest cylinder between 0.00 and -6.00 D; MRSE up to +9.00 D with cylinder between 0.00 and +6.00 D; or manifest cylinder (from 1.00 to 6.00 D) greater than the magnitude of sphere, and the cylinder and sphere have opposite signs. * BSCVA of 20/20 or better. * UCVA: * Myopes must be 20/40 or worse. * Subjects with Hyperopia or mixed astigmatism, treatment may be based on difficulty maintaining UCVA of 20/40 evidenced by spectacle/contact lens dependence for distance, as documented by the investigator. * Wavefront diameter ≥ 4.0 mm. * Sufficient agreement between manifest refraction (adjusted for optical infinity) and iDesign System refraction (sphere, cylinder, and axis) to allow treatment selection and generation of an ablation profile as determined by the investigational iDesign System software. * Manifest refraction sphere within ± 0.75 D of cycloplegic refraction sphere. * Anticipated post-operative stromal bed thickness of at least 250 microns, based on pre-operative central corneal pachymetry minus the maximum treatment depth to be ablated (as calculated by the iDesign System) and the intended flap thickness. * Anticipated post-operative keratometry value (based on pre-operative iDesign System refraction and keratometry) that is appropriate. * A stable refractive error (based on a previous exam, medical records, or prescription) as compared to the unadjusted pre-operative manifest refraction. * Subjects who currently wear contact lenses must demonstrate refractive stability in the operative eye. Rigid or toric lenses must be removed for at least 2 weeks and SCL for at least 3 days prior to the first refraction used to establish stability. A second refraction with a change of no more than ± 0.50 D MRSE at least 7 days after baseline. * Willing and capable of returning for follow-up examinations for the duration of the study. Exclusion Criteria: * Women who are pregnant, breast-feeding, or intend to become pregnant over the course of the study, as determined by verbal inquiry, or another condition associated with the fluctuation of hormones that could lead to refractive changes. * Subjects with an ametropic or amblyopic fellow eye not meeting all inclusion criteria that does not fall within the indications for treatment using the VISX® STAR S4 IR™ Excimer Laser. * Concurrent use of systemic (including inhaled) medications that may impair healing, including but not limited to: steroids, antimetabolites, isotretinoin (Accutane™) within 6 months of treatment, and amiodarone hydrochloride (Cordarone™) within 12 months of treatment. * Acute or chronic disease, illness, or treatment that would increase the operative risk (e.g., immuno-compromised, autoimmune disease, connective tissue disease, clinically significant atopic disease, diabetes, etc.). * Subjects with a cardiac pacemaker, implanted defibrillator, implanted neurostimulator, or any active electrical implants. * Ocular condition (other than high myopia) that may predispose the subject to future complications, such as history or evidence of active or inactive corneal disease * Previous intraocular or corneal surgery that might confound the outcome of the study or increase risk to the subject. * Known sensitivity or inappropriate responsiveness to any of the medications used in the post-operative course. * Concurrent participation in any other clinical study.