An eye-mountable device for measuring an intraocular pressure is provided. The device may include a transparent polymeric material having a concave surface configured to be removably mounted over a corneal surface of an eye, an antenna, an expandable member, a sensor and control electronics at least partially embedded in the transparent polymeric material. The expandable device is configured to expand and apply a force to the corneal surface and the sensor is configured to detect a resistance to deformation of the cornea in response to the applied force. The resistance to deformation of the cornea in response to the force applied by the expandable member is indicative of the intraocular pressure of the eye.
