Dk/t value : Oxygen transmissibility of a contact lens. In general,the higher these values are, the better is the oxygen transmissibility of the lens. The high level of oxygen flow to the cornea is important as it improves wearing comfort and longer term tolerance
Water content : Contact lenses with a lower water content dehydrate less on the eye than do lenses with a high water content, so they could be better for people with dry eyes. Contacts with a high water content usually have a higher oxygen transmissibility. Therefor they are more suitable for longer wear.
Silicone Hydrogel lens is combining the advantages of lower water content lenses and high oxygen permeability.So it contains less water and delivers more oxygen to the eye than traditional hydrogel lenses.
Multiple factors besides Dk/t ,wetting and dehydration characteristics,including lens modulus(degree of flexibility of a contact lens), edge profile and deposit resistance also collectively influence lens-wearing comfort.
More detail : http://www.acuvue.ca/site_en/acuvue_oasys.htm
