Get to an opticians and get the glasses sorted out first. Quite often new nose pads and a quick frame tweak will usually stop them from slipping. After that, get a good helmet, with good adjustment that fits your noggin. Mine isn't some super fancy expensive version, just a bulk rate Bell Avanti from Halfords (I'm onto my third one). The important thing is that it sits on my head comfortably and doesn't wiggle around.
Get to an opticians and get the glasses sorted out first. Quite often new nose pads and a quick frame tweak will usually stop them from slipping. After that, get a good helmet, with good adjustment that fits your noggin. Mine isn't some super fancy expensive version, just a bulk rate Bell Avanti from Halfords (I'm onto my third one). The important thing is that it sits on my head comfortably and doesn't wiggle around.