Effects of artificial tears on corneal epithelial permeability in dry eyes

The aim of this study was to detect possible changes in the permeability of the corneal epithelium in dry eye patients treated with artificial tears. For this reason, corneal epithelial permeability was measured in 68 consecutive dry eye patients before and after 8 weeks of treatment with artificial tears by means of objective fluorophotometry (polyvinyl alcohol 1.4% + chlorobutanol 0.5%, 25 subjects; polyvinyl pyrrolidone 2% + benzalkonium chloride 0.005%, 25 subjects; polyvinyl pyrrolidone 2% without preservative, 18 subjects). Before treatment, the stromal fluorescein uptake of dry eyes was three times higher than that of healthy control eyes. Eight weeks after the beginning of treatment the corneal epithelial permeability of patients treated with polyvinyl alcohol 1.4% + chlorobutanol 0.5%, as well as of those treated with polyvinyl pyrrolidone 2% without preservative, was reduced significantly (-44.9% and -43.4%, respectively; P less than 0.001). However, patients who had been treated with polyvinyl pyrrolidone 2% + benzalkonium chloride 0.005% showed no significant change in corneal epithelial permeability after treatment (-7.9%; P = 0.3).