When I got my advanced open water we were asked to write our name backwords on the surface and at 80 feet and do a simple puzzle. My times were the same at depth as on the surface so I thought was bulletproof, hahahahaha. I had several 100 foot dives and didn't notice anything so again my confidence soared. Then when getting wreck certified and learning to tie off I realized that even at 60 or 70 feet I was moving very slowly and carefully and sometimes had trouble with the coordination of setting the lines right. Yup, NO doubt, I was affected. On my aow test I simply wrote with my left hand at depth, guess what? I have always written backwords with my left hand without having to think about it. I fooled myself into thinking I was unaffected. Just increase the complexity of tasks and soon you will realize you are vulnerable.
