Yesterday I was underneath a car doing up the torque convertor bolts between the transmission and the engine. Some dirt fell into my eye and as I was trying to flick it out with my shirt sleeve I was thinking how good it would be if there was some kinda filter for our eyes. Second thought was 'Der icon, that's what safety glasses are for.' As my thoughts tend to run, it brought up the question of 'our eyes are a lens' which is pretty obvious. But I wonder what focal length our eyes are and what aperture it uses? What about iso, does that also relate to our eyes? Our eyes are pretty amazing if you ask me. Someone here might have more of a clue on this than me. Tell me what ya reckon. I'm off to see if i can find a pair of Hoya UV linear polarised safety glasses. Metal mount preferably.