The lens is located in the anterior and middle part of the eye and serves as the equivalent of a zoom lens in a camera, converging light (20D convex lens) and adjusting (zoom). The lens is a transparent tissue without blood vessels and no direct contact with the surrounding tissues, and is mainly nourished by atrial fluid. Lesions of the lens are primarily a result of loss of transparency and abnormalities in its position, both of which can cause significant visual impairment.
When the atrial fluid composition and lens capsule permeability change and metabolic disorders are caused by various reasons, the lens protein degenerates, water gaps, vacuoles and cellular epithelium proliferate between fibers, and the transparent lens becomes cloudy to form cataract. Cataract is a common and major blindness-causing eye disease, and nearly 50% of the more than 5 million blind people in China are caused by cataract. In large and medium-sized cities in China, cataracts are currently the number one cause of blindness. According to a survey on cataract disease and surgery in Beijing, the prevalence of cataract among people aged 50-60 is 6.83%, while the prevalence of cataract among people aged 70 and above is 59.95%, and 83% of elderly people aged 80 and above suffer from cataract. Analysis of the quality of life of cataract patients shows that the worse the vision of elderly cataract patients, the lower the quality of life, low vision affects the patients’ own behavior and mental condition, which is reflected in the loss of basic living ability and physical and mental health, and also increases the burden of patients’ families and society. Currently, blindness and disability caused by cataract is still an important public health and social problem in China. Cataract surgery is the only internationally recognized effective treatment method.