Comparing Silicone Hydrogel Contact Lens Wearers to Hydrogel Contact Lens Wearers and Non-lens Wearers

Inclusion Criteria

• Is between 17 and 60 years of age inclusive (age matching required between all 3 study groups), and has full legal capacity to volunteer;
• Has had a self-reported oculo-visual examination in the last two years.
• Has read and signed an information consent letter;
• Is willing and able to follow instructions and maintain the appointment schedule;
• No previous history of overnight contact lens wear or PMMA (polymethylmethacrylate) lens wear.
• Auto-refraction vertexed spherical equivalent between +4.00 and -8.00 (prescription matching required between groups 1 & 2). This criterion is non-applicable to participants in group 3.
• Is found to be in one of the study groups matched by age (±5 years), ethnicity (Asian vs. non-Asian) and CL Rx (±2.00 D) according using the following criteria.

GROUP 1: For the past (minimum) 6 months has ONLY worn spherical DDSH lenses AND prior to wearing this lens they only wore SH material lenses in the past (minimum) 3 total years.

GROUP 2: For the past (minimum) 6 months has ONLY worn spherical DDH lenses AND prior to wearing this lens they only wore H material lenses in the past (minimum) 3 total years.

• For groups 1 & 2, currently and for at least the previous 6 months has had habitual daily disposable wear schedule of at least 8 hrs a day, 5 days a week in only one material category - either silicone hydrogel or hydrogel material. This criterion is not-applicable to participants in group 3.
• Is willing to wear the study contact lens in the randomized eye for 3 hours of eye closure on the second study day. This criterion is not-applicable to participants in group 3.
• Has clear and healthy corneas and anterior eye and no active ocular disease;
• Can achieve monocular HCVA of logMAR 0.10 or better in each eye with subjective refraction or pinhole.
• Can achieve acceptable fit and comfort in the randomized eye with the study lens. This criterion will be confirmed at the baseline visit (V1). This criterion is not-applicable to participants in group 3.
• Has a wearable pair of spectacles.

Exclusion Criteria

• Is participating in any concurrent clinical trial;
• Is unable/unwilling to provide permission for the study site to seek CL history from their eye care practitioner
• Has any known active ocular disease and/or infection;
• Has a systemic condition that in the opinion of the investigator may affect a study measure or interfere with contact lens wear; this may include, but not be limited to, diabetes, hyperthyroidism, recurrent herpes simplex/zoster, Sjogren's syndromes, xerophthalmia, acne rosacea, Stevens-Johnson syndromes, and systemic connective tissue disorders e.g. rheumatoid arthritis.
• Is using any systemic or topical medications that in the opinion of the investigator may affect a study measure;
• Has known sensitivity to fluorescein dye, topical anesthetic, or products to be used in the study;
• Appears to have any active ocular pathology, ocular anomaly or severe insufficiency of lacrimal secretion (severe dry eye) that would affect the wearing of contact lenses;
• Appears to have any signs of corneal inflammation or previous infection or corneal opacity/scar;
• Is pregnant, lactating or planning a pregnancy at the time of enrolment (by verbal confirmation at the screening visit), due to potential ocular physiological changes, such as changes in the corneal shape and cell types;
• Is aphakic;
• Has undergone refractive error surgery, or has a history of any ocular surgery or injury.
• Is a toric or multifocal contact lens wearer.