The aim of this study was to investigate the effect of preoperative artificial tears on dry eye and the stability of tear film after femtosecond laser flap excimer laser in situ keratomileusis (FS-LASIK).

300 high myopia patients (582 eyes) who received FS-LASIK in Beijing Tongren Eye Center of Beijing Tongren Hospital affiliated to Capital Medical University between June 2017 and June 2018 were included as research subjects. Among of them, there were 143 males (279 eyes), and 157 females (303 eyes) whose ages were between 18 to 49 years (mean 31.1±1.2 years). Subjects were divided into two groups according to the random comparison table, 150 patients (290 eyes) per group. Before the operation, artificial tears were used 4 times per day and for 21 days in the study group. No artificial tears were used before the operation in the control group. The score on the tests of dry eye symptom, tear film break-up time (BUT), Schimer I test (SⅠt), corneal fluorescein staining score (FL) before the operation and after operation for 7, 30, 60 and 90 days were examined and recorded. All the data was expressed in the form of mean±standard deviation. Comparison between groups were conducted by applying analysis of variance for two-factor repeated measurements.

The scores of dry eye symptom of the study group and the control group were (12.00±3.16) pts and (12.32±3.15) pts, respectively. The difference between two groups was not statistically significant (t=1.334, P>0.05). The scores of the dry eye symptom of the study group after operation for 7 and 30 days were (14.20±3.20) pts and (14.60±2.65) pts, respectively; those of the control group were (16.28±3.34) pts and (16.44±3.56) pts, respectively. The data for the study group was better those of the control group, there was a statistically significant difference (t= 2.103, 2.167; P<0.05). The dry eye score of the study group after operation for 60 and 90 days were (12.89±2.67) pts and (12.04±2.88) pts, respectively; those of the control group were (13.23±2.45) pts and (12.71±3.22) pts, respectively. The difference between two groups was not statistically significant (t=1.085, 0.601; P>0.05). Before operation, the BUT, FL, and SⅠt results of the study group were (12.47±3.18) s, (0.52±0.24) pts and (14.44±2.15) mm/5 min, respectively; those of the control group were (12.31±3.11) s, (0.51±0.25) pts and (14.43±2.16) mm/5 min, respectively. The difference between two groups was not statistically significant (t=0.446, 1.547, 0.799; P> 0.05). The SⅠt results of the study group after operation for 7 and 30 days were (10.89±3.13) mm/5 min and (10.93±3.02) mm/5 min, respectively; those of the control group were (9.07±3.11) mm/5 min and (8.19±3.25) mm/5 min, respectively. The SⅠt results of the study group was better those of the control group. There was a statistically significant difference (t= 2.028, 2.350; P<0.05). The SⅠt before and after operation for 60 and 90 days of the study group were (14.14±2.34) mm/5 min and (15.10±3.15) mm/5 min, respectively; those of the control group were (14.04±2.67) mm/5 min and (14.76±3.08) mm/5 min, respectively. Comparing to the values before the operation, the differences had no statistical significance (t=1.607, 1.729; P>0.05). The BUT results of the study group after operation for 7, 30, and 60 days were (9.96±3.05) s, (10.07±2.98) s , and (10.15±3.03) s, respectively; those of the control group were (7.36±3.05) s, (7.46±2.59) s, and (7.87±2.65) s, respectively. The data after operation was lower than the values before the operation, and the difference was statistically significant (t=3.187, 2.603, 2.441; P<0.05). The overall value of the study group was better than the values for the control group, and the difference was statistically significant (t=2.304, 2.192, 2.177; P<0.05). The FL scores of the study group after operation for 7, 30, and 60 days were (1.07±0.48) pts, (1.04±0.31) pts, and (0.93±0.19) pts, respectively; those of the control group were (2.10±0.18) pts, (1.88±0.44) pts, and (1.84±0.29) pts, respectively. The data value increased after operation, and the difference between before and after operation was statistical significance (t=3.118, 2.974, 3.057; P<0.05). The overall data of the study group was better than those of the control group, there was a statistical significance difference (t=3.119, 2.053, 3.113; P<0.05). There was no statistical significance for the BUT and FL scores before and after operation for 90 days (t=0.975, 1.801; P>0.05).

Dry eye symptoms usually happen to patients with high myopia after receiving FS-LASIK, but it only lasts for a short period, recovering to the level before the operation after 90 days. The application of artificial tears before surgery could reduce the postoperative dry eye symptoms and propel the recovery of the stability of tear film, which is suggested.