The purpose of this pilot study is to compare the effect of DAILIES TOTAL1, a low water content silicone hydrogel lens, and Biotrue ONEday, a high water content hydrogel lens, on the rate of tear evaporation. The study will also serve to validate the novel, in-house developed evaporimeter.

Inclusion Criteria:

1. Is at least 17 years of age and has full legal capacity to volunteer;
2. Has read and signed an information consent letter;
3. Is willing and able to follow instructions and maintain the appointment schedule;
4. Has worn soft contact lenses for a minimum of 6 months;
5. Currently wears soft contact lenses for at least 4 days per week and 8 hours per day;
6. Has an acceptable fit and comfort with both study contact lenses in the powers available;
7. Has less than or equal to 1.00DS difference between eyes in their habitual contact lenses;
8. Is willing to be awake for at least 2 hours before visit 2;
9. Is willing to not wear eye makeup on the day of visit 2 and 3;
10. Is willing to not use eye drops or artificial tears on the day of visits 1, 2, and 3;
11. Has a wearable pair of spectacles.

Exclusion Criteria:

1. Is participating in any concurrent clinical or research study;
2. Has any known active* ocular disease and/or infection;
3. Has a systemic condition that in the opinion of the investigator may affect a study outcome variable;
4. Is using any systemic or topical medications that in the opinion of the investigator may affect a study outcome variable;
5. Has known sensitivity to sodium fluorescein dye;
6. Is pregnant, lactating or planning a pregnancy at the time of enrolment (by verbal confirmation at the screening visit);
7. Is aphakic;
8. Has undergone refractive error surgery;
9. Has a known sensitivity to petroleum jelly (Vaseline);
10. Has epilepsy and/or a sensitivity to flashing lights;
11. Wears toric contact lenses;
12. Has any physical impairment that would interfere with holding the evaporimeter;
13. Has taken part in another research study within the last 14 days.

One day

Participants and investigators are masked as to which lens is assigned to each eye.