Scanning electron microscopy
Specimens used for SEM required removal of the retinal pigment epithelium (PE), enabling visualization of the outer surface of the neural retina. Retinae from Crx-/-, rhodopsin-/-, RDS, or wildtype eyes were dissected free from PE in a dispase solution and fixed in 1.25% glutaraldehyde and 1.0% formaldehyde overnight at 4°C. Tissue was then washed 5X in cacodylate buffer and dehydrated in ascending grades of ethanol. Tissues were subsequently critical point dried in carbon dioxide. All specimens were mounted and coated with sublimated gold-palladium by the sputtering technique. Micrographs were obtained with a Jeol JSM-35CF scanning electron microscope.