The use of procion dyes for light microscopy of the frog lens

Protocols for light microscopy of frog lenses that result in good visibility of cell structure from the lens surface to its nucleus are presented. The lenses are fixed in 10% neutral formalin in 0.06 M phosphate buffer and are embedded in Epon 812. Following staining of the thick sections with selected Procion dyes, essentially every cell in the section plane of the lens can be visualized by simple light microscopy without fluorescence. The methods and dyes allow measurement of cell dimensions at all depths in the lens and allow investigation of cell packing geometry. The techniques should be generally useful for studying normal lens structure and the alteration of structure induced by cataractogenesis.