The lens is an important component of the ocular contents. The contents of the eye include the atrial fluid, the lens and the vitreous humor. The lens itself is a biconvex structure containing mainly jelly-like components that is very translucent and appears ultrasonographically as an echogenic structure. It is located between the iris and the vitreous humor and is connected to the ciliary body by the suspensory ligament. Its main role is to regulate refraction, and it is an important structure for regulating light for seeing near and far. The main abnormalities of the lens are the following: 1) change in position, which is normally between the iris and the vitreous, but can become incompletely or completely dislocated if trauma or external forces are applied; 2) clouding of the lens. Lens clouding is also called cataract; 3, congenital developmental abnormalities: such as spherical crystals, etc.