A cataract is a loss of vision caused by the lens becoming opaque and cloudy. The main manifestation is a gradual, slow loss of vision, rather than a sudden loss. This “gradually” refers to a year or two years or longer intervals, not a month or two months or a day or two. Vision loss means that there is a fog or a layer of glass in front of the eyes, and it is increasingly difficult to see. Some patients have difficulty seeing day and night, while others see more clearly at night and less clearly during the day. In some cases, the darker it is, the clearer it is, but the brighter it is, the less visible it is. This may be caused by the different types of cataracts. The greatest progress in modern ophthalmology is the application and development of cataract ultrasound emulsification technology. Generally speaking, ultrasound emulsification surgery combined with IOL implantation takes about 10 minutes and is usually done under surface anesthesia without anesthesia, so patients do not have to worry about this surgery.