Abstract: Lenses comprising first and second walls defining a cavity therebetween, which contains a fluid, are described. At least one of the walls is flexible, and the amount of fluid in the cavity can be changed to alter the shape of the at least one flexible wall, so as to alter the power of the lens. One or more flexible walls may have at least one groove formed in the wall(s) close to the periphery(ies) of the wall(s). In yet another configuration, the flexible wall and the second wall are bonded, welded, or fused together. In yet another configuration, a lens comprises a flexible wall and a second wall. The flexible wall is resilient and thinner in its central region, which is capable of being displaced relative to the second wall. Also described are methods of manufacturing a flexible wall for a lens.