For my part, I noticed that prior to my iPad 3, I always had my iPad 1 cranked up to max brightness and always got strained eyes after reading for 8 hours each day. With my iPad 3, I now find I'm running it at half brightness and I do have noticeably less eye strain. Things are so sharp, and the contrasts and colors so rich on the display, I no longer feel the need to have the brightness maxed out. I think all these factors somehow combine to improve the overall experience. I'm also quite sure when the images becomes so much sharper and richer, we can actually increase the viewing distance, which helps ease the eyes as well.