Comparing the Effect of 2 Artificial Tear Formulations on Daytime Ocular Surface Parameters After Orthokeratology Contact Lenses Wearing

Purpose: To compare the ocular comfort and tear film stability of low viscous and medium viscous lubricant eye drops in orthokeratology lens users. Method: This is a prospective, two-arm, randomized, crossover trial. After a 7±2 day run-in and washout period, subjects were assigned to apply one of two eye drops to the orthokeratology lens bow every night before inserting their lenses. Low viscosity eye drops with sodium chloride 5.5 mg (AIM Artificial Tears, Aimedicine) and medium viscosity eye drops with 0.4% polyethylene glycol (Systane ULTRA Unit dose, Alcon) were used. Results: The study included 40 subjects with a mean age of 10.40±2.64 years and an averaged spherical equivalent of−3.43±1.31 diopters. There were no significant differences in Ocular Surface Disease Index (OSDI), Schirmer,noncontact tear film break-up time (NiTBUT), corneal staining score (NEI), or topographic decentration between the two treatment groups. Conclusion: Despite the disparity in viscosity, the difference in visual acuity, OSDI, Schirmer, NiTBUT, NEI, and topographic decentration failed to reach statistical significance. Therefore, wearing orthokeratology lenses with low or medium viscosity artificial tears did not significantly impact daily visual acuity, ocular surface parameters, or contact lens centration.