By now the military must have some cool eye tracking kit.
Way back in the seventies, I was at an arms fair where a four barrel 20mm AA rig attracted my attention.
The whole thing was slaved (yes I know) to a helmet that projected a cross hair in the sky so thst you just had to follow an aircraft with the cross and the cannon would follow.
The sales drone was telling a Middle Eastern looking gentleman that they were developing an eye tracking version so that the gunner didn't have to move his head quite so much to track a target.
Can't remember the maker but may have been Lockheed.