Viscous corneal protection by sodium hyaluronate, chondroitin sulfate, and methylcellulose

The authors' study of the viscosities of various concentrations of sodium hyaluronate, chondroitin sulfate, and methylcellulose revealed that sodium hyaluronate and methylcellulose are pseudoplastic fluids in contrast to chondroitin sulfate, which is a Newtonian fluid. Pseudoplastic fluids are ideal for maintaining the anterior chamber, since they are more viscous at rest. Intermediate viscosity preparations of these three agents used as a thin endothelial coating gave excellent protection from intraocular lens abrasion. A highly viscous agent, eg, sodium hyaluronate 1%, in a thin layer produced extensive endothelial cell damage because it transmitted excessive shear force to the endothelium. A highly viscous agent, sodium hyaluronate 1% in a thick layer produced a physical barrier to compression with little endothelial damage. A low-viscosity agent, balanced salt solution provided insufficient protection against intraocular lens abrasion.