Evaluation of the Performance of Monthly Replacement Sphere Lens Designs in Habitual Soft Contact Lens Wearers

Inclusion Criteria: * Is at least 18 years of age and no older than 35 years, and has full legal capacity to volunteer; * Has read and signed an information consent letter; * Is willing and able to follow instructions and maintain the appointment schedule; * Self-reports having a full eye examination in the previous two years; * Self-reports spending on most days at least 6 hours cumulative (not necessarily in one single stretch) using digital devices such as a computer, laptop, tablet, e-reader, smartphone; * Has healthy eyes with no health condition or medication that contra-indicate contact lens wear, in the opinion of the investigator; * Anticipates being able to wear the study lenses for at least 8 hours a day, 6 days a week; * Habitually wears soft frequent replacement contact lenses, for the past 3 months minimum (NOTE: the habitual contact lens brand is restricted such that no more than one third are to be the Biofinity brand (or their equivalent private label brand name) and no more than one third are to be an Alcon brand; * Has refractive astigmatism no higher than -0.75DC in each eye; * Can be fit and achieve binocular distance vision of at least 20/30 Snellen (Available lens parameters are sphere +6.00 to -6.00D, 0.25D steps). Exclusion Criteria: * Is participating in any concurrent clinical or research study; * Has any known active ocular disease and/or infection that contraindicates contact lens wear; * Has a systemic or ocular condition that in the opinion of the investigator may affect a study outcome variable; * Is using any systemic or topical medications that in the opinion of the investigator may affect contact lens wear or a study outcome variable; * Has known sensitivity to the diagnostic sodium fluorescein used in the study; * Self-reports as pregnant, lactating or planning a pregnancy at the time of enrolment; * Has undergone refractive error surgery or intraocular surgery.