Carbonic anhydrase distribution in the human and monkey eye by light and electron microscopy.

The distribution of carbonic anhydrase (CA) in the eye of man and three species of monkeys was studied by light and electron microscopy using the histochemical method of Hansson. Carbonic anhydrase staining was found in the corneal endothelium. In monkeys the endothelial cells covering the inner surface of the operculum were also stained, whereas in the human the staining stopped at Schwalbe's line. In the trabecular meshwork no cells exhibited CA staining. The iris dilator muscle showed some staining, while no clear staining was found in the pigment epithelium (PE). In the ciliary body both the PE and the non-pigmented epithelium (NPE) displayed CA staining, most prominently in the basal and lateral membranes but also discernible in the cytoplasm. The staining of the NPE (but not the PE) showed clear-cut regional differences, and the presence of CA coincided with morphological indicators of secretory activity. Heavy staining was found in the capillaries under the ciliary epithelium. In the pars plana many capillaries showed staining of only that part of the circumference of the vessel wall which faced the epithelium. Unstained segments were also found in many choroidal capillaries under the pigmented epithelium of the retina. In the retina itself CA stain was found in the pigmented epithelium, in the Müller cells and in capillaries supplying the inner retina (only monkey retina was studied).(ABSTRACT TRUNCATED AT 250 WORDS)