I m wondering if I m going to need glasses. I have an appointment for the first time. Some words seem blurry far away sometimes, and up close on a computer seems blurry, but I can see. I also have headaches while reading a screen, and when looking at words sometimes there seems to be a shadow of the words under them, along with blurry. My question mainly is, how off does my eyesight have to be to need glasses.