A portable electronic apparatus has a portable electronic device, a lens assembly, a control unit and a display module. The portable electronic device has a shell with a chamber and an opening communicating with the chamber. The lens assembly is mounted in the opening of the shell. The display module is mounted in the chamber of the shell. The control unit is mounted in the portable electronic device to control the display module to project various object images into a user's eyes. The user can exercise the eyes by releasing the eye muscles, tightening the eye muscles, rolling the eyes upwards, downwards, leftwards, rightwards, or rolling the eyes circularly when the user looks at the projected object images. Vision defects, such as myopia and astigmatism, can be relieved.