Filtration surgery is a medical procedure primarily used to treat conditions like glaucoma, which is characterized by increased pressure in the eye. The surgery aims to create a new drainage pathway for fluid, helping to lower intraocular pressure and prevent damage to the optic nerve. During the procedure, a small opening is made in the eye to allow excess fluid to escape. This can be done using various techniques, including the placement of a shunt or creating a trabeculectomy, which is a common type of filtration surgery. The goal is to improve vision and maintain eye health.