Fluorescence assay for measuring lipid deposits on contact lens surfaces

A simple fluorescence assay for estimating the propensity of the contact lens surface towards the uptake of lipids and formation of lipid deposits has been developed. The assay is based on the incubation of the contact lenses with an artificial tear-lipid mixture, staining of the lenses with a fluorescent lipid probe, Nile Red, and subsequent macroscopic imaging of the fluorescent lipid deposits on the contact lens surface with a thermoelectrically cooled charge-coupled device (CCD) camera. The results of the assay show that statistically significant differences in the formation of lipid deposits exist between the surfaces of different contact lens materials.