[spiderplant]

Originally Posted by OLD BOY

I don't think it's anything to do with eyesight! You simply get a much sharper picture with HD. If watching on a larger screen, SD pictures are grainy. If you watch HD all the time, and then tune into an SD channel, the difference is very noticeable indeed.

It can be a lot to do with eyesight. If you can't see SD-sized pixels at your viewing distance, making the pixels smaller won't make any difference to you.