The paper presents a theoretical analysis of properties of a specific liquid membrane lens composed of two axially symmetric membranes of different thicknesses and double curvature. These membranes enclose a space where an optical liquid is filled. Mechanical and optical properties of the lens are then changed by varying the volume of the liquid. The paper presents new formulas for calculation of membrane deflections, radii of curvatures of the membranes, and axial geometry, which offer to minimize the third-order spherical aberration of the lens for an object at infinity. The presented theory is examined on specific examples.