After my entry on ergonomic keyboards, I saw one of the Google ads here for SmartNAV, a hands-free mouse.

It’s a device that sits on top of the monitor and you steer it with a dot you glue to your forehead, the tip of your nose, your glasses or hat. Good for people with spinal injuries, it says. You can have a footswitch to click with your feet. There is more than one device there, and I haven’t read everything, but maybe this link is of interest to someone.