one month dispensing study comparing the clinical performance of the comfilcon a sphere lenses compared to comfilcon a asphere lenses.

Conditions: Myopia

Summary: this is a prospective, multi-center, subject-masked, bilateral wear, one month dispensing study comparing the clinical performance of the subjects' habitual comfilcon a sphere lens (control) following a refit with comfilcon a asphere lens (test). after the dispensing visit, subjects will return for follow-up evaluations after 2 weeks, and 1 month.

this is a prospective, multi-center, subject-masked, bilateral wear, one month dispensing study comparing the clinical performance of the subjects' habitual comfilcon a sphere lens (control) following a refit with comfilcon a asphere lens (test). after the dispensing visit, subjects will return for follow-up evaluations after 2 weeks, and 1 month. both comfilcon a sphere lens (control) and comfilcon a asphere lens (test) are coopervison lenses.

Eligibility criteria:
inclusion criteria a person is eligible for inclusion in the study if he/she: * is between 18 and 34 years of age (inclusive) * has had a self-reported eye exam in the last two years * is an adapted comfilcon a sphere contact lens wearer * uses digital devices, (e.g. computer, tablet, smart phone, ipad), for more than 4 hours a day, 5 days a week. * has a contact lens spherical prescription between -1.00 to -6.00 (inclusive) * has a spectacle cylinder no greater than 0.75d (diopters) in each eye. * can achieve best corrected spectacle distance visual acuity of 20/25 (0.10 logmar) or better in each eye. * can achieve a distance visual acuity of 20/30 (0.18 logmar) or better in each eye with the study contact lenses. * has clear corneas and no active ocular disease * has read, understood and signed the information consent letter. * has a contact lens refraction that fits within the available parameters of the study lenses. * is willing to comply with the wear schedule (at least 5 days per week, \> 8 hours/day assuming there are no contraindications for doing so). * is willing to comply with the visit schedule exclusion criteria a person will be excluded from the study if he/she: * has a history of not achieving comfortable cl (contact lens) wear (5 days per week; \> 8 hours/day) * presents with clinically significant anterior segment abnormalities * presents with ocular or systemic disease or need of medications which might interfere with contact lens wear. * presents with slit lamp findings that would contraindicate contact lens wear such as: * pathological dry eye or associated findings * significant pterygium, pinguecula, or corneal scars within the visual axis * neovascularization \> 0.75 mm in from of the limbus * giant papillary conjunctivitis (gcp) worse than grade 1 * anterior uveitis or iritis (or history in past year) * seborrheic eczema of eyelid region, seborrheic conjunctivitis * history of corneal ulcers or fungal infections * poor personal hygiene * has a known history of corneal hypoesthesia (reduced corneal sensitivity) * has aphakia, keratoconus or a highly irregular cornea. * has presbyopia or has dependence on spectacles for near work over the contact lenses. * has undergone corneal refractive surgery. * is participating in any other type of eye related clinical or research study. * is habitually using rewetting/ lubricating eye drops (more than once per day)