Artificial Tear Instillation-Induced Changes in Corneal Topography

This study aims to compare changes of corneal topography (Galilei G4) before and after the instillation of artificial tears in patients with dry eye disease (DED). Corneal topography was performed in patients 1 min before and after artificial tear instillation. Two types of artificial tears were used: 1% polysorbate 80 (PSB) and 0.5% carboxymethylcellulose (CMC). Of 135 patients, PSB and CMC were instilled in 101 and 34 eyes, respectively. The average value of Sim K increased significantly after instillation (44.07 +/- 2.26 diopter (D)) compared to before (43.90 +/- 2.02 D, p = 0.006) the instillation of artificial tears. Mean Sim K astigmatism was statistically increased after PSB instillation (1.48 +/- 2.17 D) compared to before instillation (1.31 +/- 2.10 D, p = 0.049). An axis change of astigmatism 10 degrees or more after artificial tear instillation was found in 51.9% of patients, and 30 degrees or more in 20.0% of patients. Increased Sim K value and significant changes in the astigmatic axis in the corneal topography were observed after instillation of artificial tears in DED patients. PSB instillation had a greater effect on corneal keratometry values than CMC instillation.