1. Reporting. We know numbers are less than reported because BALPA had a survey done which showed half their members had been hit at least once and that only about 2/3 of the attacks were actually MOR'd. Air Pilots came up with similar stats. Don't forget half the CAT traffic in the UK is from overseas, and they report to their own NAA; if they don't call it to ATC it doesn't show on the UK stats.
2. If you have seen a laser flash, it has by definition hit you in the eye. An oblique laser strike that you perceive in your peripheral vision will hit the relevant portion of your retina and if it is strong enough, that is where you will have your injury. If you were looking at it directly, then it will (if strong enough) affect your central vision.
3. Test purchases have been examined by specialist labs in the last few months. Result, there is at least one 3W hand-held device in the UK, bought easily over the Internet and fortunately in the care of a responsible organisation.