Any clouding of the clear lens is collectively referred to as a cataract. The lens is a non-vascular tissue, and its nutrition mainly comes from atrial fluid. When various reasons cause changes in the permeability and metabolic disorders of the atrial fluid component and the lens capsule membrane, cataracts are formed when the lens protein degenerates and changes such as water gaps, vacuoles and cellular epithelial proliferation occur between fibers. There are several types of cataracts that can cause glaucoma. 1.When the clouding of senile cataract gradually aggravates, the cortex absorbs water and swells, the lens volume increases and pushes the iris forward to make the anterior chamber shallow. If there are anatomical factors of closed-angle glaucoma, the acute attack of glaucoma is often induced by the swelling of the crystal and the shallowing of the anterior chamber. 2. In mature cataract, due to the long duration of cataract, usually after several years, the water in the lens continues to be lost and the volume shrinks, the capsule membrane wrinkles, the anterior chamber deepens, the crystal fiber decomposes and melts into milky liquefaction, the crystal nucleus sinks, the lens capsule membrane degenerates, thins and ruptures spontaneously, the liquefied cortex leaks outside the lens capsule, causing allergic ophthalmia, and the lens cortex, which exists in the atrial water for a long time, is blocked. The anterior chamber angle can cause secondary (open angle) glaucoma, also known as lens dissolving glaucoma. 3. In over-ripe cataracts, degenerative changes often occur in the suspensory ligament of the lens, causing dislocation of the lens or violent vibration may cause the lens nucleus to dislodge from the ruptured capsule membrane and fall into the anterior chamber or vitreous, which may also cause secondary glaucoma. In addition, after cataract surgery, trauma that causes the lens cortex to spill over may cause secondary glaucoma.