In the EEROS library you will find a directory with examples. Open a shell in the build directory of your EEROS library and run examples/controlsystem/mouseTest. This examples reads four axis of a mouse together with three buttons and outputs the results periodically.
In order to read from the proper mouse events you can install and run the evtest program.

$ sudo apt-get install evtest
$ sudo evtest

This programm will list all connected devices together with the associated event number. Please adapt the program accordingly. It might be necessary to run it with root priveledges.