To determine if the 'Defocus Incorporated Soft Contact' (DISC) lens slows myopia progression in Hong Kong schoolchildren using simultaneous vision approach.

The investigators hypothesize that the natural process of emmetropization in human is regulated by the equilibrium between the opposite hyperopic and myopic defocus. A sharp focus of retinal image (foveal fixation) is fundamental for co-ordination of the equilibrium. The DISC lens is a custom-made multi-zone bifocal soft contact lens which is based on simultaneously provides clear vision and defocus at all viewing distances. It comprises of correcting zones for correcting distant prescription(correction of refractive error, and defocusing zones to incorporate constant myopic defocus for slowing down myopia progression.

Inclusion Criteria:

• Age 8-13 years
• Myopia (SE) between -1D to -5D
• Astigmatism less than or equal to -1D
• Anisometropia: less than or equal to 1.25D
• aided VA (monocular): 0.00 log MAR or better
• willingness to wear contact lens constantly
• availability for follow-up for at least 2.5 years
• parents' understanding and acceptance
• willing to provide refractive status of grandparents

Exclusion Criteria:

• Severe ocular or systemic allergies
• Taking any medication that might have an impact on contact lens wear or that might influence the outcome of the clinical trial
• Ocular or systemic condition that might affect refractive development
• Strabismus at distance or near
• Prior use of bifocal or progressive lenses
• Prior use of rigid gas permeable lenses and Ortho-K lenses