The purpose of this study is to investigate if the blue-light filtering spectacle lenses promote myopia progression in schoolchildren.

The effect of blue light on ocular health has been studied extensively. Shorter wavelength such as blue light could cause damage to the retina. The damage was more evident in the ageing eye. Since the tablets and mobile with blue LED backlight display are widely used, thus blue-light filtering spectacle lenses are now available in the market. However, whether this kind of lenses could affect the eye growth in schoolchildren is unknown. This study is then designed to investigate if the blue-light filtering spectacle lenses affect myopia progression in Hong Kong Chinese schoolchildren. The schoolchildren will be randomly allocated to either blue-light filtering spectacle lens group (treated) or conventional spectacle lens group (control). Their axial length and refraction will be monitored every 6 months for 2 years. The changes between two group will then be compared.

Inclusion Criteria:

• Refraction: myopia of -1.00 dioptres (D) to -5.00D
• Astigmatism: equal or less than -1.50D
• Anisometropia: equal or less than 1.00D
• Best corrected monocular visual acuity: 0.0 LogMAR or better after full correction
• Parents' understanding and acceptance of random allocation of grouping

Exclusion Criteria:

• any ocular and systemic abnormalities might affect visual functions or refractive development
• prior treatment of myopic control, e.g. drugs, orthokeratology, progressive addition lenses, bifocal lenses, drugs (e.g. atropine), etc.