Silicone hydrogel (SH) contact lenses have shown marked improvement over conventional hydrogel lenses by allowing extended periods of wear time without inducing corneal hypoxia. To promote wearability, SH lenses rely on siloxane-based polymers, rather than water, for oxygen transport through the bulk of the lens. However, theses SH contact lenses suffer from low water content - it could result in dry eye symptoms such as irritated, scratchy and red eyes when wearing them. Thus, it was necessary to incorporate hydrophilic coating on the surface of SH contact lens. In this study, the surface of SH lenses was exposured to UV-O₃ or O₂ plasma to introduce hydroxyl group on the surface, and then silanized with a silane coupling agent. We will present the content of adsorbed hydroxyl group and silane coupling agent with the condition of surface treatment.