Effect of Increased Power and Asphericity of Highly Aspherical Lenslets on Myopia Control Efficacy: A Contralateral Crossover Study

Purpose: The study aims to evaluate whether the myopia control efficacy of spectacle lenses with Highly Aspherical Lenslet Target (H.A.L.T.) technology could be further improved by a combined increase of power and asphericity of lenslets. Methods: Fifty Singaporean myopic children aged 6 to 10 years were enrolled in a randomized, contralateral, crossover clinical trial. Two different myopia control spectacle lenses were tested: lenses with H.A.L.T. technology and lenses with maximized H.A.L.T. (H.A.L.T. MAX) technology. One group (N = 25) was assigned to wear H.A.L.T. MAX on the right eye and H.A.L.T. on the left eye, and the other group (N = 25) to wear the opposite combination for 6 months. The combinations were switched for the next 6 months. The primary outcome was the change in axial length (AL). Results: At baseline, mean (±SD) AL of eyes wearing H.A.L.T. and H.A.L.T. MAX lenses was 23.97 ± 0.84 and 23.99 ± 0.84 mm. After the first 6 months, mean (±SEM) axial elongation in eyes wearing H.A.L.T. and H.A.L.T. MAX lenses was 0.105 ± 0.016 and 0.043 ± 0.016 mm (P < 0.001), respectively. After the crossover, the corresponding mean AL change was 0.123 ± 0.014 and 0.077 ± 0.013 mm (P < 0.001). The differences in AL change between the two lenses were correlated with faster axial elongation with H.A.L.T. lenses in both phases. Conclusions: Spectacle lenses with H.A.L.T. MAX technology slowed axial elongation more effectively than spectacle lenses with H.A.L.T. technology and might be particularly beneficial for children with faster axial elongation. Translational Relevance: The relationship between the optical characteristics of lenslets and axial elongation offers a new avenue for developing more effective myopia control lenses.