When you reach the point of not being able to read up close without stretching your arms out, you need to consider prescription reading glasses.
Ready-made reading glasses are fine for occasional use, however most people do not have exactly the same prescription in both eyes. Headaches, eye strain, and even nausea can result from wearing reading glasses that are not made to your individual prescription.
Also, don't confuse reading glasses with glasses for VDU and computer use. If you're using reading glasses to try to view your computer screen, you may strain your eyes and cause headaches. Reading printed matter is done at a closer range than viewing on a computer screen.
The options for reading glasses include single vision, bifocal, occupational and varifocal lenses. Bifocal means two points of focus: the main part of the spectacles lens contains a prescription for distance vision, while the lower portion of the lens holds the stronger, near prescription for close work. Occupational or enhanced reading glasses are designed to provide optimal viewing areas for computer and office work. They will have limited or no distance areas and are not suitable for driving or outside wear. Varifocal lenses incorporate distance, computer and reading areas and may be worn all the time.
Regular eye check-ups are important to determine your eye health and vision needs.