Why can I not see up close as well as I did when I was younger?

It’s called presbyopia.

All of us notice an important change in our vision sometime around the age of 45. It seems like we wake up one day and can’t focus up close. Perhaps this change was more gradual – it became difficult to see menu items or credit card statements in a dimly-lit restaurant, or price tags and caller ID weren’t as clear, but as long as we held our arms out a little further, we could read. But one day, we ran out of arm length, and reading glasses or progressive lens glasses became a constant companion. This condition is called presbyopia, and comes from the gradual hardening of the lens in the eye. As we age, the lens doesn’t flex well to shift focus between distance and near, and reading becomes difficult without magnification. Presbyopia afflicts everyone over the age of 45.