Last year I almost got run over when an ild guy in a Carina missed his turning and drove right over the traffic island I was on... The sort with ramps for crossing points. I swear, he never even realised what he'd done, and he only missed me because I jumped. A week later, the same guy was killed when he got confused and turned down a railway track at a level crossing. That's nothing to do with eyesight, it's just mental incapacity to drive, and that's a bit harder to test for.
OTOH, my grandad was still driving until his late 80s, and for most of that time he was fune, but then he became aware that he was having slight blackouts. He gave the car to my brother the next day. (coincidentally, my brother wrote it off 3 months later after going straight on when he should have gone right, and flying 20 feet into a field- that was mental incapacity to drive too

)
I'd agree in principle that there should bemore testing, but I don't know how to make it work, is all- there's no easy, quick way to test for that sort of mental agility. I also reckon every driver should have to do an eye test every 10 years or so regardless of age- you need to be able to see to a set standard to learn to drive, why shouldn't the same be true afterwards.