An example head-mounted display device includes a light projector, an optical assembly arranged to direct light from a light projector to a user, and an actuator module. The optical assembly includes a variable focus lens assembly including a rigid refractive component, a shaper ring defining an aperture, and a flexible lens membrane between the shaper ring and the rigid refractive component and covering the aperture. The refractive component, the shaper ring, and the lens membrane are arranged along an axis. The refractive component and the lens membrane define a chamber containing a volume of fluid. The actuator module is configured to adjust an optical power of the variable focus lens by moving the shaper ring relative to the refractive component along the axis, such that a curvature of the lens membrane in the aperture is modified.