Cataracts themselves do not cause eye pain. One of the age-related cataracts is called cortical cataract, which is generally divided into four stages: the initial stage, the expansion stage, the maturation stage, and the over-ripe stage. The causes of eye pain are secondary to intraocular inflammation or elevated intraocular pressure, also known as glaucoma, and are as follows: 1. Expansion of the lens occurs during the expansion phase, resulting in abnormal intraocular structures that can compress the anterior angle. The anterior angle is the structure in the eye that produces water flow out of the eye, i.e., the discharge channel. Once squeezed, it can cause the fluid in the eye to be unable to be removed, which in turn leads to high intraocular pressure, which means that an acute attack of glaucoma may occur during the expansion phase, when eye pain, headache, nausea, vomiting, etc. occur; 2. cortical cataract, in which the cortex in the cataract in the overripe phase liquefies and can overflow into the lens capsule bag, which is equivalent to the coat After overflowing the capsular bag, it will produce crystalloid glaucoma. The nucleus of the lens may block the pupil, causing an obstacle to atrial water flow, which can cause glaucoma, and then eye pain, headache and other related symptoms.