how can I connect a Garmin GPS etrex vista hcx to macbook pro with retina.

have you tried? and if so, what happened?

I believe that Garmin GPSr model uses a USB connection, so if you load the Garmin drivers, and possibly the [free] Garmin Base Camp utility, you should be able to connect your GPSr to your macbook Pro and transfer information. I don't recall positively, but I think that your GPSr should appear as a USB drive automatically once you connect it, but it might require you to load the Garmin Communicator software.