Myopia Control Using Bright Light Therapy, Myopic Defocus and Atropine

The present study is a multi-arm randomised clinical trial with a 24-month duration. Subjects will be healthy Hong Kong Chinese schoolchildren with low to moderate myopia. The aims are to determine the clinical effectiveness of bright light therapy on inhibiting myopia progression in schoolchildren, and to determine whether combination therapy using bright light therapy (BLT) and myopic defocus is more effective than monotherapy.

Study population Seven hundred and sixty Hong Kong Chinese children (152 in each) of A. Control group, B. BLT only group, C. BLT and Defocus Incorporated Multiple Segments (DIMS) group, D. BLT and atropine 0.01% group) and E. Atropine 0.01% group aged 7-12 years old will be recruited. They must not have had prior or current myopia control treatment, have no ocular or systemic diseases/abnormalities that affect visual function, refractive development or spectacle lens wear, and no previous intraocular or corneal surgery. They must not have allergy to atropine.

The eligible subjects will be randomly assigned into one of the four groups. Their cycloplegic refraction and axial length will be monitored every six months for 2 years. The changes in refractive errors and axial length between groups will be compared.

Inclusion criteria

• Myopia of at least -0.75D (spherical equivalent) in both eyes
• Age at enrolment: 7-12 year; Hong Kong Chinese
• Astigmatism and anisometropia: 1.50D or less
• Spectacle corrected monocular visual acuity (VA): 0.0 logMAR or better
• Parents' understanding and acceptance of random allocation of grouping and masking
• Able to wear the prescribed spectacle, put on eye drop and undergo light therapy daily.

Exclusion criteria

• Eye disease or binocular vision problems (e.g., strabismus, amblyopia, oculomotor nerve palsies, corneal disease, etc.)
• Previous intraocular or corneal surgery
• Systemic disease that may affect vision, vision development (e.g. endocrine, cardiac and respiratory diseases, diabetes, Down syndrome, etc.)
• Allergy to atropine
• Previous gas permeable, soft bifocal, or orthokeratology contact lens wear or bifocal/PAL/specific myopic control spectacle wear or use of atropine or pirenzepine (longer than 1 month of wear)
• Previous or current participation in myopia control studies