Some games are still using vJoy to send eye tracking input and since it is a third party software, we can unfortunately not provide a fix. So, for now, you need to use an earlier build than 1903 of Windows 10 for vJoy to work.
Games using vJoy
IL-2 Sturmovik: Battle of Stalingrad
Flight Simulator X
Farming Simulator 15
7/16/19 There is a new release of vJoy which we have tested and it can be installed and used on Windows 10 1903.