Abstract: A portable electronic device system provides features to assist a visually impaired or elderly end-user. The system includes a protective case for the portable electronic device, which facilitates the handling and usability of the device for visually impaired or elderly end-users. The case includes a replaceable extension unit, enabling many different sorts of extension unit accessories to be swapped in and out. The system includes a software application executable on the portable electronic device, which enables the device to switch to another and simpler user interface which also enables control of the features or functions provided by the specific extension unit that has been fitted.