Tear osmolarity after cataract surgery

PURPOSE: To evaluate the changes in tear film osmolarity and Schirmer I test after cataract surgery. METHODS: This single-center, prospective study included patients with no subjective complaints about dry eye disease. Patients with the following conditions were excluded: contact lens wearers, patients with diabetes, pseudoexfoliation, pterygia, and eye drops users. The eye that had not undergone surgery was considered the control group. Tear osmolarity and Schirmer I test were evaluated before surgery and during the first postoperative month. RESULTS: Thirty-seven patients were enrolled in the study. Before surgery, tear osmolarity was 301.2 ± 15.09 Osm/L in the study group and 302.3 ± 14.21 mOsm/L in the control group (P = 0.2), while Schirmer I test averaged 13.4 ± 10.50 mm in the study group and 13.7 ± 10.79 mm in the control group (P = 0.6). The next morning, the tear osmolarity decreased to <275 mOsm/L in the study group while in the control group, the value increased to 303.1 mOsm/L ± 13.68 (P = 0.008). The Schirmer I test in the same morning showed an increase up to 19.9 ± 9.73 mm in the study group and to 15.7 ± 10.19 mm in the control group (P = 0.01). One week later, the tear osmolarity increased to 311.8 ± 14.85 mOsm/L, while the control group averaged 301.7 ± 11.84 mOsm/L (P = 0.013). The Schirmer I test results decreased to 15.8 ± 9.37 mm in the study group and 13.9 ± 10.19 mm in the control group (P = 0.07) one week after the surgery. One month after surgery, tear osmolarity and Schirmer I test results in the study group decreased to the control group level (P > 0.05). CONCLUSIONS: The tear osmolarity results increased to the dry eye disease level in the first postoperative week. Over the course of one month, the difference in tear osmolarity and Schirmer I test values for the study and control groups leveled off.