Preparing thick sections of frozen adult Drosophila retinas for microscopy

This protocol is used for light microscopic analysis of the adult Drosophila eye. It provides nice preservation of pigment granules and photoreceptor rhabdomeres. Therefore, it is used primarily for phenotypic and mosaic analysis of adult eyes. Because this fixation method does not preserve either cell membranes or subcellular structures, transmission electron microscopy (TEM) is recommended for visualizing these structures.