Although there are many accessibility options integrated into modern operating systems and software applications, increasing the default zoom level of received messages in Microsoft Outlook remains surprisingly complicated and inhibiting. I have recently been assisting with computer setup and tutoring of a friend who has macular degeneration, which makes it increasingly difficult to read small text. One of the more difficult tasks was personalizing Outlook 2016 to make the baseline text much larger with minimal required user interaction. Below is a summary of my tribulations and my most recommended way to configure Outlook for those with advanced vision impairment.
These instructions should be equally applicable to Outlook 2010 and Outlook 2013, but have not been tested.