Why is my eyesight worse some days than others?
I have trouble seeing far away a bit (I don't have terrible vision, it's like 20/30 with mild astigmatism, but it's enough to make a huge difference when in lectures at school), so I got glasses about a year ago to wear primarily while in class. I was told that I could wear them all the time if I wanted, but it doesn't really matter much. Well some days, especially when I'm tired, my eyes just can't focus period, and I have to wear my glasses all day if I want to be able to function. Is this normal/why does it happen? I know that it's common for eyesight to get worse as time goes on, and I've noticed that mine has, and I'm sure that some day I'll have to wear glasses/contacts full time, but now, it seems a bit weird.