Abstract
PURPOSE: A performance comparison of two myopia control spectacle lens designs, defocus incorporated multiple segments (DIMS) and highly aspherical lenslets (HAL), at slowing myopia progression in a European child/adolescent population. Previous research directly comparing these designs has been limited to Chinese participants and 1-year follow-up. The prevalence of myopia in European child/adolescent has been estimated at 22.60%. METHODS: Retrospective cohort study of individuals (6-17 years) with myopia progression. Participants wore DIMS (Hoya MiyoSmart) or HAL (Essilor Stellest) spectacles for a minimum of 2 years. Axial length (AL) and cycloplegic autorefraction (spherical equivalent refraction (SER)) were measured at baseline and 1 and 2 years. RESULTS: Mean 1-year SER changes for DIMS were -0.34D (±0.46 SD) and HAL -0.30D (±0.30); 2-year changes for DIMS were -0.50D (±0.64 SD) and HAL -0.63D (±0.56). Mean 1-year AL increases for DIMS were 0.19 mm (±0.56) and HAL 0.15 mm (±0.47); 2-year increases for DIMS were 0.29 mm (±0.63) and HAL 0.32 mm (±0.72). For equivalence margins of 0.25D and 0.50D for SER at 1 and 2 years, respectively, and similarly 0.20 mm and 0.30 mm margins for AL, DIMS and HAL lenses were equivalent apart from AL at 1 year where the 0.21 mm 95% CI upper limit just exceeded 0.20 mm. At both 1 and 2 years, none of the differences in mean SERs or ALs between DIMS and HAL were clinically or statistically significant (p≥0.05 Mann-Whitney U test). Using linear mixed model analysis, the interaction between lens type and time did not significantly affect SER or AL at 1- or 2-year follow-up (p≥0.05). 38.4% of children/adolescents with DIMS had no SER progression at 2 years, compared with 21.9% with HAL (p=0.047). CONCLUSION: In a European population, DIMS and HAL lenses are essentially equivalent in their ability to reduce myopia progression and AL elongation over a 2-year follow-up period.