The purpose of this study is to examine the efficacy and performance of the Defocus Incorporated Multiple Segments (DIMS) and a variant of DIMS (D2) spectacle lenses on controlling myopia progression in fast progressing myopic children.

DIMS spectacle lens is a multifocal spectacle lens that produces myopic defocus images and corrects distance refractive errors at the same time.

Participants will be prescribed a pair of DIMS spectacle lenses. Their cycloplegic refraction and axial length will be monitored every 6 months over the first 2 years. They will then be prescribed with a pair of D2 spectacle lens for an additional 2 years. D2 is the variant of Defocus Incorporated Spectacle lenses. It is a multifocal spectacle lens that produces myopic defocus images and corrects distance refractive errors at the same time.

Inclusion Criteria:

• SER: -1.00D or below
• Documented history of fast progressing myopia, either in SER or AL
• SER progression: 0.50D/year or more
• AL elongation: 0.27mm/year or more
• Best-corrected monocular visual acuity (VA) in both eyes: 0.00 logMAR (equivalent) or better
• Acceptance of random group allocation and the masked study design
• Anisometropia of 1.50 D or less
• Astigmatism of 2.00 D or less

Exclusion Criteria:

• Strabismus and binocular vision abnormalities
• Ocular and systemic abnormalities
• Prior experience of myopia control