A microapparatus (11) implantable in the eye (13) includes a cuasi-bistable microvalve (21) commanded by an intraocular pressure sensor (23) in situ. The microvalve mechanism includes a diaphragm (27) made of a conjugated polymer (29) that shows high deformation and biocompatibility capabilities and which volume depends from the electric potential applied by its pair of electrodes (31). The sensor and actuator-valve are coupled to a drainage conduit (15), the first to deform by the pressure in the ocular globe and the second in a position of buckling to normally close the drainage conduit. The sensor has a membrane of conductive polymeric material with these same properties and whose ohmic resistance varies with the mechanical deformation produced by the ocular pressure.