Abstract: Disclosed is a variable lens assembly having a water chamber defined with a front lens holder between two flexible, transparent diaphragms and filled with a fluid, and a syringe connected to the front lens holder and controlled to vary the volume of the water chamber. The diaphragms are stretched to curve outwards and form into a biconvex lens as the plunger of the syringe is pushed forwards in compressing the fluid; the diaphragms are induced to curve inwards and form into a biconcave lens as the plunger of the syringe is pulled backwards in releasing the fluid.