Ultrastructure of contusion cataract.

We investigated the histopathologic condition of four lenses with contusion rosette cataract by light and electron microscopy; periods between blunt trauma and cataract extraction varied from 4 months to 40 years. The initial morphologic changes appear to be the formation of intercellular vacuoles within the lens epithelium and the swelling of superficial cortical lens fibers. Signs of beginning fiber degeneration within the edematous zone include fragmentation of fiber cytoplasm into droplets and globules, formation of abnormal membrane arrangements, and enlargement of intercellular spaces. Late rosette opacities manifest as sharply demarcated layers of vacuolic degeneration in the deeper cortex. We suggest that in contusion cataract, a traumatically induced dysfunction of the lens epithelium leads to an edema of superficial cortical lens fibers that subsequently undergo degeneration and produce a localized and permanent lamellar zone of vacuolation. With time and with the formation of new clear lens cells, this layer becomes gradually compressed and displaced deeper into the cortex.