An optical device with a deformable membrane including an anchoring area on a support helping to contain a constant volume of liquid in contact with one of its faces, a substantially central area, configured to be deformed reversibly from a rest position, and an actuation mechanism displacing the liquid in the central area stressing the membrane in at least one area situated strictly between the central area and the anchoring area. The actuation mechanism is electrostatic and includes at least one pair of opposing electrodes, one of the electrodes of the pair being at the level of the membrane, the other being at the level of the support, the electrodes being separated by dielectric, the dielectric being formed at least by the liquid.