First, buy your reading glasses as soon as you get your glasses prescription, many older people do not wearing reading glasses whey they have problems with presbyopia, this will add to the reading difficulties, resulting in dizziness and other symptoms of bulging eyes, the impact of life and work. As time goes, the original prescription would be not is accurate for the reading glasses, you have to re-get your glasses prescription and buy new reading glasses.
You must get your reading glasses prescription first, then buy the glasses, do not try this and that, wearing improper prescription glasses will make your eye worse.
To consider the needs and habits of the use of reading glasses, also known as “light feet”, that is put on reading glasses after the last point can be moved before the general reading of about 30 cm distance. However, if your table is relatively low, or engaged in the maintenance of the machine, then the last point in more than 30 cm; the other hand, if your work closer to the last point in less than 30 centimeters. Therefore, with reading glasses to the optometrists tell when you need to make the appropriate adjustment of lenses. Some middle-aged and older need to see which looks nearly the help of glasses; it should be with the two glasses. If the two glasses too much trouble, you can choose from top to bottom increasing refractive multimodal lens gradient.