Comparative Study of Two Marketed Spherical Soft Contact Lenses

The study will evaluate the daily wear performance of the Avaira (enfilcon A) spherical lens during two weeks of wear compared to Vistakon's Oasys (senofilcon A) spherical lens.

Inclusion criteria

Subjects must satisfy the following conditions prior to inclusion in the study:

• Based on his/her knowledge, must be in good general health.
• Be 18 to 38 years old.
• Be able and willing to adhere to the instructions set forth in this protocol and complete all specified evaluation.
• Read, indicate understanding of, and sign Written Informed Consent.
• Be existing or successfully adapted users of soft contact lenses, but not currently wearing either of the study lenses being evaluated in this trial.
• Require a visual correction in both eyes.
• Require a prescription between +8.00D and -12.00D and have less than -0.75D of astigmatism in both eyes.
• Achieve visual acuity of 20/25 or better in each eye with a spherical contact lens prescription.
• Must be able to wear their lenses at least 10 working days over the next 2-weeks; > 8 hours/day assuming there are no contraindications for doing so.
• Have normal eyes with no evidence of abnormality or disease. For the purposes of this study a normal eye is defined as one having: no amblyopia; no evidence of lid abnormality or infection (e.g. entropion, ectropion, chalazia, recurrent styes); no clinically significant slit lamp findings (e.g. infiltrates or other slit lamp findings Grade 2 or above: corneal edema, tarsal abnormalities, and conjunctival injection); no other active ocular disease (e.g. glaucoma, history of recurrent corneal erosions, cornea [infiltrates], conjunctiva, lids, and intraocular infection or inflammation of an allergic, bacterial, or viral etiology); no aphakia

Exclusion criteria

Any of the following will render a subject ineligible for inclusion:

• Greater than 0.50D of refractive astigmatism in either eye.
• Presbyopic or current monovision contact lens wear.
• Cannot be currently wearing of either lenses (Avaira or Oasys)
• Presence of clinically significant (grade 2-4) anterior segment abnormalities; inflammations such as iritis; or any infection of the eye, lids, or associated structures.
• Presence of ocular or systemic disease or need of medication which might interfere with contact lens wear.
• Slit lamp findings that would contraindicate contact lens wear such as: pathological dry eye or associated findings; pterygium, pinguecula or corneal scars within the visual axis; neovascularization > 0.75 mm in from the limbus, giant papillary conjunctivitis (GPC) worse than Grade 1; anterior uveitis or iritis (past or present), seborrheic eczema, seborrheic conjunctivitis, history of corneal ulcer or fungal infections; poor personal hygiene
• A known history of corneal hypoesthesia (reduced corneal sensitivity).
• Contact lens best corrected Snellen visual acuities (VA) worse than 20/30.
• Aphakia, Keratoconus or a highly irregular cornea

To be eligible to enter the study, subjects must have ALL of the inclusion criteria and NONE of the exclusion criteria present.