A head-wearable electronic device includes a frame worn on a head of a user and an electro-optical device coupled to the frame. The electro-optical device includes a display module generating a data image, an optical module, and a camera module. The optical module includes a first switchable mirror layer and a second switchable mirror layer, each having a light transmittance that is controllable. The first switchable mirror layer provides the second switchable mirror layer with the data image generated by the display module and the second switchable mirror layer provides eye of the user with the data image provided from the first switchable mirror layer. The camera module provides an external image having information about the eye of the user corresponding to an operation of the first and second switchable mirror layers.