ECCE for Subluxated Hypermature Cataract
A Morgagnian cataract arises when a cortical cataract becomes hypermature. A cortical cataract is an opacity of the lens cortex or periphery of the lens. An early cortical cataract is often clinically diagnosed by spoke-like or wedge-shaped opacities of the lens, most commonly in the inferior quadrants. As the cataract matures, the lens fibers degenerate, leaving cytoplasmic protein globules between the fibers of the cortical lamellae. Increasing amounts of cortex degenerate with time, and the globules begin to coalesce creating large accumulations of liquefied lens protein. When the majority of the cortex is affected, the lens nucleus is left floating in the liquid cortex, forming a Morgagnian cataract (Albert 2008).
Eyes with hypermature or mature cataracts may develop a form of secondary elevated intraocular pressure referred to as phacolytic glaucoma. Because of the increased concentration of protein molecules under the lens capsule, water is drawn from the aqueous into the lens capsule via osmosis. This may result in a swollen, tense lens capsule. Lens proteins may leak from microscopic rents in the capsule. These proteins trigger a non-granulomatous inflammatory response. Macrophages collect in the anterior chamber and phagocytize the free lens proteins. Both the protein-laden macrophages and the protein itself clog the trabecular meshwork, hindering aqueous outflow and causing elevated intraocular pressure (BCSC 2010). With the increase tension on the lens capsule, there is an increased risk of spontaneous capsular rupture or rupture with only mild trauma. Exposure of the lens nucleus and cortical material to the anterior chamber after rupture can cause a severe granulomatous inflammatory reaction, phacoantigenic endophthalmitis. On histology, the lens material is surrounded by multinucleated giant cells, lymphocytes, and histiocytes in concentric layers (BCSC 2010).