A device and method are presented for use in non-invasive measurement of a patients intra-ocular pressure (IOP). The device comprises a probe unit comprising a flexible membrane which is to be brought into contact with a patients eyelid thereby enabling a contacting region of the membrane to match a shape of the eyelid defined by the shape of the patients cornea. The device is configured to enable controllably varying application of force to the membrane against the eyelid and to enable illumination of the membrane at least within the contacting region thereof, the deformation of the illuminated membrane affecting detected light returned from the membrane, thereby enabling identification of a condition of applanation of a desired area of the membrane by identifying desired data indicative of the detected light and allowing the IOP measurement upon identifying said condition.
