In general, from the age of 55 onwards, the distance that can be clearly seen with the naked eye (without glasses) is greater than 0.86 meters, while for reading purposes, the distance that can be clearly seen with+2.50D (i.e. 250 degrees) reading glasses is approximately 0.27-0.40 meters. This creates a blind spot at a distance of 0.5-0.7 meters, which happens to be the second most commonly used distance for guests (doing household chores, shopping, using computers...). Therefore, without secondary visual supplementation for this blind spot, the guest's eyes will often be in a state of fatigue at the distance of the blind spot, whether naked or using reading glasses, invisibly accelerating the development of presbyopia. If you need reading glasses with a reading distance of+2.50D (i.e. 250 degrees) or above, for your own needs and visual health, prepare a pair of reading glasses at an arm length of about 70cm, that is, choose a reading distance of+1.50D (150 degrees) lower than the applicable reading distance reading glasses for use outside of reading. Foreign users of presbyopic glasses do not remove their presbyopic glasses from their eyes, and they can be paired with several pairs of different degrees of presbyopic glasses according to their needs, which can be used in turn; Foreign glasses are also packaged and sold together with several pairs of presbyopia glasses of different degrees, while in China, one pair of presbyopia glasses is worn out, reaching+4.00D (400 degrees) before the age of 60, which deepens the degree of presbyopia and affects the health of vision.