Easy technobabble fix - the visor suppresses the optical neurons, or it simply acts as a blindfold so the real eyes see only darkness. LaForge’s pain was because the tech wasn’t fully developed. I forget if he still had the pain with the prosthetic eyes. Hackability is another problem we probably won’t have in the real future because of quantum encryption or whatever, but it’s still a good plot device present-day people can relate to - no matter how unrealistically it’s portrayed - click-click-click… “okay, I’m in!” LOL.