Lens-induced glaucoma may occur as either secondary angle-closure or open-angle glaucoma. Dislocation or swelling of the lens can cause pupillary block and subsequent angle-closure glaucoma. Leakage of soluble lens proteins from a relatively intact cataractous lens can result in a severe secondary open-angle glaucoma (phacolytic glaucoma). Heavy molecular weight protein, believed to be of lens origin, has now been identified in 12 of 12 anterior chamber specimens from such patients. This liberated lens protein can directly obstruct the trabecular outflow pathways. After extracapsular cataract surgery or after lens trauma, liberated fragments of lens material may mechanically impair the drainage of aqueous humor through the outflow channels (lens particle glaucoma). The diagnosis and management of these different lens-induced glaucomas are reviewed. With proper recognition, these glaucomas are promptly cured by the surgical removal of the lens (material).