An eye assembly for use in a patient simulator is provided. The eye assembly includes an iris diaphragm having a moveable inner portion defining an opening. The inner portion of the iris diaphragm is movable radially from a first position wherein the opening has a first diameter and a second position wherein the opening has a second diameter greater than the first diameter. The iris diaphragm is configured for use in a simulated eye. The eye assembly also includes a dilation actuator in communication with the inner portion of the iris diaphragm for selectively moving the inner portion between the first and second positions to simulate dilation of an eye.