Get your eyes tested regularly by an ophthalmologist or optometrist. Once a year is standard. If any of the following are a problem, you may wish to schedule an appointment sooner. Look at an object that is far away that you tend to see a lot. If it looks blurrier than you remember, or you just think you have trouble seeing things you once could see easily, your eyes probably aren't as good as they used to be. Look really closely at something. A book or newspaper will work. If you have trouble reading the print, your eyes probably aren't as good as they used to be. But this is true only if you at one point were able to read the print, obviously. If step two or three caused you to second guess your sight, go to an eye care professional for an eye exam. They can tell you for sure if you need to start wearing glasses. If you have any doubt in your mind, go just in case.
Belinda