Glaucoma surgery is a relatively routine procedure in ophthalmology, and the principle of the surgery is to artificially make a channel that can act as a drain when the intraocular pressure rises. A complication of this surgery is the development of a shallow anterior chamber after glaucoma surgery, which is mainly due to the filtration channel being too open. There are three general grades of shallow anterior chamber: in the first grade, the iris in the periphery is in contact with the corneal endothelium, or the central anterior chamber is about half as shallow as it was before surgery. In the second grade, all of the iris is in contact with the corneal endothelium, except for the lens or vitreous in the pupillary area, where a fissure-like anterior chamber still exists between it and the corneal endothelium. In the third grade, the iris, lens, and vitreous body are in complete contact with the corneal endothelium, and the anterior chamber disappears.