The timing of cataract surgery is not the earlier or later the better, but mainly based on the patient’s own wishes. There is a structure in the human eye called the lens. The lens is completely transparent under normal conditions, like the lens of a camera, but as it ages, the transparent lens will gradually cloud up, rather than suddenly, so cataracts are usually a slow process of development. Cataract surgery needs to depend on how high the patient’s requirements for visual function are, and there is no absolute standard. For example, in the past, it was required to operate when the vision declined to the point where only manual or only light could be seen, and because of the limitations of surgical equipment and surgical techniques, surgery could only be performed at a late stage. Nowadays, due to the continuous advancement of technology and equipment, cataract surgery can be considered whenever the lens becomes cloudy, cataracts appear, and vision loss affects the usual quality of vision. The current recommended standard is 0.5, which means that surgery can be done when the corrected visual acuity decreases to 0.5.