This content is PDF only. Please click on the PDF icon to access.
Abstract
Electron microscopy of 3 normal human retinas has provided evidence which generally supports the conventional ideas that have been based on light microscopy of Midler's cells. This study has revealed even greater cytoplasmic differences between the inner and outer halves of Midler's cells than has been appreciated in the past: the inner has properties of fibrous astrocytes whereas the outer resembles oligodendrocytes. Certain structural characteristics of the inner part of the outer plexiform layer give it both the appearance and properties of a limiting membrane. This structure tends to restrain the passage of hemorrhages and exudates out of the outer plexiform layer; we have proposed the name "middle limiting membrane" for this distinctive zone.