Comparison of osmolarity of various artificial tears products commercially available in South Korea

Purpose: To compare the osmolarity of various artificial tear products commercially available in the Republic of Korea. Methods: The osmolarity of the artificial tears was analyzed using TearLab^® and Multi-Osmette™. We divided the artificial tear products into five groups, including hypo-osmolar 0.18% sodium hyaluronate (HA), iso-osmolar 0.1%, 0.15%, 0.3% HA, and 0.5% carboxymethylcellulose sodium (CMC), and measured three products per group. Results: Among the 12 products of iso-osmolar artificial tears, there were seven products (58.3%) < 300 mOsm/L, and among the three products of hypo-osmolar artificial tears, there were two products (66.6%) < 150 mOsm/L. A significant difference (p < 0.05) was observed between the iso-osmolar 0.3% HA group and the hypo-osmolar 0.18% HA group. In the iso-osmolar 0.1% HA and 0.15% HA, the difference between the products in each group was approximately 12 mOsm/L, and the CMC group had the smallest deviation among products, which was close to 300 mOsm/L. There was a significant difference of 305.57 ± 6.38 mOsm/L in the iso-osmolar 0.15% HA group, 293.44 ± 8.71 mOsm/L in the 0.1% HA group, and 285.67 ± 3.67 mOsm/L in the 0.3% HA group (p < 0.001). There was no significant difference in osmolarity between the iso-osmolar products containing HA and CMC (p = 0.117). Conclusions: There was a difference in osmolarity between the published and actual measured values of commercial artificial tears, and there was a difference in osmolality depending on the content of HA and the manufacturer.