Evaluation of sodium hyaluronate as viscous vehicle for eye drops.

The influence of sodium hyaluronate and hydroxyethylcellulose on the elimination of a fluorescent tracer from the precorneal area of human eyes is investigated using a slit lamp fluorophotometer. The rheological characteristics of the equiviscous ophthalmic solutions are examined. Both viscosity enhancing polymers improve significantly the residence of the tracer in the tear film. The high viscous sodium hyaluronate solution is better tolerated than the hydroxyethylcellulose solution.