• An unpreserved artificial tear substitute containing 0.1% sodium hyaluronate was compared with a preparation containing 1.4% polyvinyl alcohol and 0.5% chlorobutanol in a controlled, double-masked, randomized study in patients with moderately severe keratoconjunctivitis sicca. Patients were evaluated initially, at 1, 4, and 8 weeks. The dry-eye status was evaluated by means of tear-film osmolality, tear breakup time, rose bengal staining, Schirmer's test (without anesthesia), and ocular surface-impression cytology. In general, neither preparation was found to be superior to the other. In both study groups, the mean tear-film osmolality and rose bengal staining score improved over the eight-week study, but the degree of squamous metaplasia of the bulbar conjunctival surface, as shown by impression cytology, did not change significantly.
Nelson JD, Farris RL. Sodium Hyaluronate and Polyvinyl Alcohol Artificial Tear PreparationsA Comparison in Patients With Keratoconjunctivitis Sicca. Arch Ophthalmol. 1988;106(4):484-487. doi:10.1001/archopht.1988.01060130530029