The Impact of Contact Lens Care Solutions on the Thickness of the Tear Film and Contact Lens

Abstract

To determine the impact of compositional differences in contact lens care solutions on the thickness of the tear film during contact lens wear. A randomized, crossover, investigator-masked clinical trial was conducted to compare AMO's Complete MoisturePlus to Alcon's Opti-Free Express in 31 subjects. The primary outcome of this study was a comparison of prelens tear film (PLTF) and postlens tear film (PoLTF) thickness values obtained during the first 2 hours of etafilcon A hydrogel lens wear. Each solution was used by each participant for a period of 7 days, separated by a washout period of 1 day. Alternative outcomes studied included prelens tear film thinning rates, solution preference, and dry eye-related symptom scores. Tear film thickness measurements were made using a noninvasive wavelength-dependent interferometric system. The average overall PLTF thickness over the 120-minute time period after using Complete MoisturePlus was 3.02 +/- 1.07 microm, whereas the average overall PLTF thickness in this same time interval after using Opti-Free Express was 2.72 +/- 0.86 (P = 0.003). For both solutions, the PLTF could be fitted by the sum of an exponential decay plus a constant. The PLTF decay amplitudes did not statistically differ when the solutions were compared (P = 0.11). There was no difference in overall PoLTF thicknesses when the average values after using each solution were compared (P = 0.57), although there was a difference immediately after the lens was applied to the eye (Complete MoisturePlus average = 4.10 versus Opti-Free Express average = 3.48, P = 0.02). The PoLTF also demonstrated an exponential decay for both solutions. The PoLTF decay amplitudes did not statistically differ (P = 0.14). Twenty subjects (64.5%) preferred Complete MoisturePlus to Opti-Free Express (35.5%) (P = 0.11), and nearly every subject (90.3%) suggested "comfort" as their reason for preference. Complete MoisturePlus is associated with a thicker PLTF when compared with Opti-Free Express in contact lens wearers without dry eye symptoms, especially during the first 5 minutes following lens insertion.