The two conditions, myopia and presbyopia, do not cancel each other out. Many people have the misconception that myopic people do not get presbyopia because the myopia will be gradually cancelled out after middle and old age. In fact, this concept is wrong, because myopia and presbyopia are two different refractive states, and the two will not cancel out. Myopia is caused by an increase in the refractive power of the eye, such as the elongation of the eye axis, which results in a loss of distance vision and blurred vision of distant objects. Presbyopia is a degenerative disease, which is caused by a decrease in the eye’s ability to adjust after the lens has hardened, so there will be a decrease in near vision, which generally manifests itself as difficulty in reading at close range and prefers to place the reading target farther away so as to see clearly. For people who are nearsighted, these two conditions exist at the same time after middle age, when they need to wear two pairs of glasses, one pair of myopic glasses and one pair of presbyopic glasses.