I saw most of people above 40 years wear glasses while reading due to presbyopia. Nearly all of the older people develop presbyopia. Why this happens? It is involved with an age-related process, which is different from astigmatism, nearsightedness and farsightedness. There are many theories about this subject. One of the most popular saying is that presbyopia comes from thickening and flexibility lost gradually as time goes by. With the lost of protein in the lenses, the lens will harder and less elastic. So does the same changing happen to the muscle fibers around the lens? All of these changes above make the eye difficult to see fine details.
Well, generally speaking, when people age, it is possible to have presbyopia. You should know that Presbyopia is a condition, caused by aging, in which people find it difficult to read small words at close distances or to work on the computer for long periods of time. And according to some experts, presbyopia generally is believed to stem from a gradual thickening and loss of flexibility of the natural lens inside your eyes. And also, in common, these age-related changes occur within the proteins in the lens, making the lens harder and less elastic over time. So it is hard for the eye to focus up close. And then the presbyopia can occur.