Pigment ispersion syndrome (PDS) is an affliction of the eye that, if left untreated, can lead a form of glaucoma known as pigmentary glaucoma. It takes place when pigment cells slough off from the back of the iris and float around in the aqueous humor. This is not what causes problems; however, if the pigment flakes clog the trabecular meshwork, preventing the liquids in the eye from draining, pressure can build up inside the eye. This pressure can cause permanent damage to the optic nerve.