Originally Posted by OptixWizard

Lipids are waxy compounds found in living cells. They form the outermost layer of moisture on the eye. Since lipids are waxy or oily, they act to keep the eye moist by reducing evaporation. Since contact lenses ride on this lipid layer, some of it is bound to stick to them. This is natural and not harmful, although if these deposits accumulate, the contact lens will be uncomfortable to wear. All you have to do is clean the Acuvue Advance contact or replace it if you've been wearing it for about two weeks and you're good to go.