The strength of reading glasses, also known as the diopter, is measured in units of diopters (D). The diopter represents the amount of magnification provided by the lens. A higher diopter number means that the lens provides more magnification, and a lower diopter number means that the lens provides less magnification.
Normal reading glasses strength typically ranges from +1.00 to +3.50 diopters. The exact strength you need depends on the extent of your presbyopia and your individual visual needs. A general rule of thumb is to start with a low diopter, such as +1.00 or +1.50, and gradually increase the strength as needed.
It is important to note that reading glasses are not a substitute for a comprehensive eye exam, and it is always best to consult with an eye doctor to determine the best solution for your vision needs. Your eye doctor can evaluate your visual acuity and perform a series of tests to determine the appropriate strength of reading glasses for you.