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April 1992

Preservative-Free Artificial Tear PreparationsAssessment of Corneal Epithelial Toxic Effects

Author Affiliations

From the Eye Research Institute (Drs Berdy and Abelson and Mss Smith and George) and Department of Ophthalmology (Drs Berdy and Abelson), Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston.

Arch Ophthalmol. 1992;110(4):528-532. doi:10.1001/archopht.1992.01080160106043

• Scanning electron microscopy was used to evaluate the corneal epithelium of rabbit eyes after administration of two preservative-free ocular lubricants, preservative-free artificial tear-1 (Hypotears PF) and preservative-free artificial tear-2 (Refresh), and 0.02% benzalkonium chloride. Animals were randomly assigned to either mild or exaggerated use regimens. A quantitative rating system was used to assess epithelial damage. With mild use, scanning electron microscopy revealed normal epithelial morphologic characteristics for both preservative-free artificial tear solutions (mean relative damage score, solution 1, 0.75±0.16; solution 2, 1.02±0.23), which were not significantly different from eyes treated with phosphate-buffered saline (1.38±0.38) or a mild dosage regimen of 0.02% benzalkonium chloride (1.20±0.12). Exaggerated use with preservative-free artificial tear solutions (solution 1,1.31±0.21; solution 2, 1.35±0.08) induced minimal damage that was not different from control eyes treated with phosphate-buffered saline (1.26±0.13). Compared with an exaggerated use of 0.02% benzalkonium chloride (4.0±0.16), both preservative-free artificial tear solutions induced significantly less epithelial damage (P =.0001). These results suggest that with frequent-dosage regimens, preservation-free artificial tear solutions-1 and -2 are free of the toxic effects associated with preserved solutions.