First sign is polychromatic luster of the posterior polar subcapsular region. No posterior synechiae. Large mutton fat KP's. Usually cataract is subcapsular posterior polar which gradually progresses to complete opacification of the lens. Usually the opacity begins posteriorly with polychromatic luster and then spreads to other regions of the lens.
Etiology is considered allergic, usually a hereditary tendency.
Bilateral opacification usually beginning in the third decade of life. Starts subcapsularly at the posterior pole and spreads to involve the entire lens. Poor control of diabetes may be a predisposing factor. Affects predominantly younger persons and tends to progress rapidly to a mature opacity, sometimes within a few days. Usually preceded by a sudden and progressive myopia.