Cataracts are not contagious. The lens in the human eye is transparent from childhood, and as it ages, the oxidation process can occur, and after it becomes cloudy, it is called cataract, and the common types are as follows: 1. Age-related cataract: it is a disease caused by various factors, and more young patients can also develop cataracts, collectively called age-related cataracts, which is the main type of cataract, usually aged 50-60. This is the main type of cataract, which usually occurs between the ages of 50 and 60. 2. metabolic cataract: for example, high blood sugar in diabetic patients causes crystal clouding; 3. radiation cataract: patients in highland areas are often exposed to ultraviolet rays, which can lead to this type of cataract; 4. congenital cataract: congenital cataract can cause amblyopia in children. It is caused by trauma to the eye. When the refractive medium causes the loss of vision in the human eye, surgery is required. Early cataracts can be treated with medication, and later, as the vision of the human eye decreases, surgery is required.