Distribution of freezable and non-freezable water in bovine vitreous.

The viscoelastic behavior of and the transport of molecules in the vitreous is influenced by the binding of water to the macromolecular components. The macromolecular components are unevenly distributed in the vitreous. Therefore, it is of interest if the bound water, which can be identified with the non-freezable water content, is also unevenly distributed in the vitreous. Differential scanning calorimetric measurements between -30 degrees C and 15 degrees C were performed on samples from different regions of bovine vitreous body. From the endotherms the amount of freezable water content was calculated. The total water content of the vitreous was measured by vacuum dehydration. There is a slight increase in the non-freezable water content when one proceeds from the lens to the retina along the optic axis. The average amount of non-freezable (bound) water content of the vitreous is high, approximately 20% of the total water content.