Osmotic tolerance of rabbit and human corneal endothelium
H. F. Edelhauser, A. M. Hanneken, H. J. Pederson and D. L. Van Horn
Rabbit and human corneas were mounted in a specular microscope and perfused
with a balanced salt solution of varying osmolality (200 to 500 mOsm).
Measurements of corneal thickness were made throughout the perfusion
period, and at selected times the corneas were fixed and prepared for
scanning and transmission electron microscopy. A hypo-osmotic perfusion
medium caused an increase in corneal thickness; by comparison, a
hyperosmotic perfusion medium decreased corneal thickness in both rabbit
and human corneas. Despite the marked changes in corneal thickness and the
water movement that occurred across the endothelium, the cellular
ultrastructure remained intact. In reversal studies (return to 300-mOsm
perfusion medium), corneal thickness returned to control values with no
marked changes in endothelial cell structure. These data indicate that the
corneal endotheium can tolerate a wide range of solution osmolalities (200
to 400 mOsm) without marked endotheial cell breakdown if the essential ions
are present.
