The electrical properties of any tissue are intimately related to the maintenance of cellular volume. The electrical properties of the lens are conferred by four anatomical structures: the membranes of the anterior epithelium, the membranes of the lens' fibers, the gap junctions electrically connecting the lens' cells, and the tiny intercellular volume. We are using microelectrodes to perform frequency domain impedance studies of the lens under normal conditions and when subjected to bathing media of abnormal ionic composition or containing pharmacological agents. Impedance studies allow us to separately determine the electrical parameters describing each anatomical structure within the lens, thereby isolating the effect of each experimental intervention to the correct structure. In this way we hope to characterize a normal lens and understand how cellular volume is maintained. The same studies will then be performed on experimental models of cataracts and we hope to identify early changes that might lead to a loss of volume regulation in these lenses.