Diffractive optical elements with optical power

A head mounted display system configured to project light to an eye of a user to display augmented reality image content in a vision field of said user, said head-mounted display system comprising:

• a frame configured to be supported on a head of the user;
• an image projector configured to project images into the user's eye to display image content in the vision field of the user;
• at least one camera;
• at least one waveguide;
• at least one coupling optical element configured such that light is coupled into said waveguide and guided therein, said at least one coupling optical element comprising a diffractive optical element having optical power;
• and
• at least one out-coupling element configured to couple light guided within said waveguide out of said waveguide and direct said light to said camera,
• wherein the camera is disposed in an optical path with respect to said at least one out-coupling optical element to receive at least a portion of the light that is coupled into said waveguide via the coupling optical element and guided therein and that is coupled out from said waveguide by said out-coupling coupling element such that images may be captured by said camera.