The secondary glaucoma refers to a heterogenous group of conditions in which the intraocular pressure is elevated as a complication of an underlying ocular or systemic disease. Some secondary glaucomas are self-limited and result in little or no permanent damage, but others are protracted, relentless, and blinding. Secondary glaucomas are classified according to etiology and pathogenic mechanisms. Just as in the primary glaucoma, the pathogenic mechanisms may be separated into open-angle and closed-angle varieties.