When do you use reading glasses? what are the guidelines?

When you can't see: Presbyopia is the loss of focusing in your eyes for near vision. It happens to everyone to some degree starting in your forties. Using readers simply helps to bring the focus back at a near point. The loss of reading vision is progressive and will naturally get weaker into your 60-70's and then level off. You can try the weakest readers first (+1.25) and gradually move up if you need more.