Neuroglial Relationships in the Human Retinal Capillary Network.

THE investigation described in this paper was designed to throw light on one aspect of the vascular relationships in the human posterior retina; such investigations contribute to the more ambitious attempts to solve the difficult and obscure problem presented by the vascular changes in diabetic retinopathy. New and fruitful ideas on retinal structure, function, and pathology have been put forward in the studies of this serious disorder by Ashton (1959), Bloodworth (1962), and Cogan, Toussaint, and Kuwabara (1961). In particular, Cogan has emphasized the important functional relationships of Muller's cells; in the retina these modified astrocytes provide a clear example of the supporting function of neuroglia; their interrelationship with the capillary circulation in glucose metabolism has been shown to be crucial for retinal function. Special interest therefore attaches to detailed studies on the intimate structural relationships of the capillary endothelium in the posterior retina and to regional differences in glial distribution in relation to the capillary networks. In retinal research, the numerous cell types, complex interrelationships, and differences in characteristics from many central nervous cells, make new methods or modifications of standard techniques for nerve tissue of special importance in the determination of glial cell type and relationships and indicate the need for caution in interpretation.