The effect of calcium on the lens ultrastructure.

The influence of a calcium-enriched solution on pig lens cell structure was studied in vitro. The morphological changes which occurred 20 min or 2 h after bathing in the solution were studied by transmission electron microscopy. After 20-min incubation, small intercellular vacuoles containing membranous and amorphous substance occurred mainly in the epithelial cells. The cytoplasm of the cortical fibers had already been dissolved at this stage. Here the membrane was disrupted and the extracellular spaces widened. After 2-h incubation, the epithelial cells were compressed by adjacent swollen fibers. However, vacuolization in the epithelium had decreased at this stage. At the cortical fiber zone, vacuolar formation had increased extensively. Vacuolization was mainly observed in the intercellular spaces between the intact gap junctions. After 2 h, the main alterations were membrane disruptions and advancing dissolution of the cytoplasm. Deeper cortical fibers were swollen but showed no extracellular vacuoles.