Purpose: To analyze the effect of lens material alone on myopia progression in a multi-center non-randomized prospective study of daily wear hydrogel and continuous wear silicone hydrogel contact lenses.
Methods: Refractive error data from completing subjects were collected during a 3-year study of 54 subjects wearing low-Dk/t hydrogel contact lenses for daily wear and 230 wearing silicone hydrogel contact lenses for up to 30 nights continuous wear. Univariate analysis of refractive error changes was first conducted on factors of lens type, age at baseline, and baseline refractive error. Multivariate analysis was then performed to control for potential confounders of age (categorical by decade and continuous), and baseline refractive error.
Results: Multivariate analysis showed that refractive error changes were significantly affected by lens type (F = 78.2, p < 0.001, R = 0.218) and subject age (F = 131.2, p < 0.001, R = 0.319) but not baseline refractive error (F = 2.56, p = 0.11, R = 0.009). The model's overall R value is 0.376; the age-adjusted refractive error changes are +0.02 D for the silicone hydrogel contact lens wearers and -0.41 D for the hydrogel contact lenses for the 3-year follow-up period.
Conclusions: Subject age and lens type significantly influenced the degree of myopic progression, with younger subjects and low-Dk/t hydrogel contact lens wearers increasing more during the study. The Lotrafilcon A silicone hydrogel lens material may contribute to less myopia progression in adult contact lens wearers.