A variable focus optical device (100) can include first optically transparent membrane (102) and a second membrane (104) that at least partially define a chamber (106) retaining an optically transparent liquid. A transparent piston (110) is attached to the second membrane (104). At least one actuator (112a-c) is operatively coupled to the transparent piston (110) and configured to move to change a focal length of the variable focus optical device (100) via actuation of the transparent piston (110). Three curved bimorph actuators (112a-c) can surround and be coupled to the piston (110) for actuation of the piston (110) to generate a plano-convex or plano-concave lens via the membranes (102, 104). A smart eyeglasses system includes a pair of variable focus optical devices (100), an object distance sensor, a battery, optional eye-tracking camera(s), and a microcontroller, collectively used for purposes of sensing distance of objects and adjusting said focal length via the variable focus optical devices (100).