Efficacy of repeated low-level red-light therapy in myopia control in schoolchildren: a randomized controlled trial

INTERVENTION: The device used in this study is a semi‐conductor laser product (Eyerising International Pty Ltd, Melbourne, Australia), emitting low‐level red‐light with a wavelength of 650 ± 10 nm. Based on calculations done by the manufacturer, the device provides light at a power of 2.00 ± 0.50 mW. The device embedded software enables the device to connect to the internet with an automated diary function to record the date and time of treatment sessions, as well as to control light emission as per the predefined treatment schedule (3 minutes per session, 2 sessions per day, with a minimum 4‐hour interval, 5 days a week, evaluated at 1 month, 3 months, 6 months, and 12 months after enrolment). The intervention period is for 12 months. Prior to the examination, the study personnel will obtain informed consent from the parents or guardians of the subjects. Eligibility criteria will be assessed. Instruction will be subsequently provided on how to use the device through a video demonstration. The video will be provided to parents for review at any time. In addition to continuing routine activities, and wearing their own single‐vision spectacles to correct myopia, subjects in the intervention group will be treated with a therapy device twice a day from Monday to Friday, three minutes per session, with a minimum interval of 4 hours, under the supervision of their parents. Each child in the intervention group will have a unique corresponding personal account and password, and the therapy device will be initiated for treatment after logging into the system prior to use. Intervention compliance monitoring Subjects will need to enter their unique accounts and password details and log in prior to the commencement of each treatment session. The device is connected to a centra CONDITION: Eye ‐ Diseases / disorders of the eye Myopia; ; Myopia PRIMARY OUTCOME: Change in Axial Length measured at the 12‐month follow‐up visit compared to baseline. Five measures of AL will be conducted on each eye prior to cycloplegia using partial coherence interferometry IOLMaster (Carl Zeiss 500, Meditec, Oberkochen, Germany) and averaged if the desired precision (i.e., < 0.10 mm) is achieved.[12 months after enrolment] INCLUSION CRITERIA: 1) Provision of consent 2) Age: >=8 and <= 13 years at enrolment 3) Myopia: Spherical equivalent refractions (SERs) under cycloplegia: ‐1.00 to ‐5.00 diopters (D) 4) Astigmatism of 2.50 D or less 5) Anisometropia of 1.50 D or less 6) Corrected monocular logMAR visual acuity (VA): 1.0 or better 7) Consent to participate in random allocation of grouping 8) Fluent in English 9) Willing and able to participate in all required activities of the study SECONDARY OUTCOME: Structual optical coherence tomography (OCT) scans. [1‐, 3‐, 6‐, and 12‐month after enrolment. ] Choroidal thickness (ChT) measured at baseline compared to the 1‐, 3‐, 6‐, and 12‐month follow‐up visits. For choroidal thickness (ChT), participants will undergo optical coherence tomography with pupil dilation and under standardized mesopic light conditions at the baseline examination and each follow‐up visit. The thickness (the distance between outer choroid‐scleral margin and RPE‐Bruch’s complex) will be obtained automatically with the assistance of OCT software.[1‐, 3‐, 6‐, and 12‐month after enrolment. ] Corneal curvature (CC) measured at baseline compared to the 1‐, 3‐, 6‐ and 12‐month follow‐up visits. Five measures of CC will be conducted on each eye prior to cycloplegia using partial coherence interferometry IOLMaster (Carl Zeiss 500, Meditec, Oberkochen, Germany).[1‐, 3‐, 6‐, and 12‐month after enrolment. ] Cycloplegic spherical equivalent refraction (SER, myopia progression) measured at baseline compared to the 1‐, 3‐, 6‐ and 12‐month follow‐up visits. Refraction data will be measured at each eye using an autorefractor (KR‐8800, Topcon, Tokyo, Japan) three times and averaged if the desired precision (i.e., spherical and cylindrical power < 0.25 D, axis < 5 degree) is achieved. Cycloplegia will be achieved using 1 drop of 0.5% Alcaine (Alcon, Puurs, Belgium) followed by 3 drops of 1% cyclopentolate (Alcon, Puurs, Belgium) to each eye at 0, 5, and 20 minutes. Pupil light reflex and pupil diameter will be checked to confirm full cycloplegia. The SER is calculated by using the sum of the spherical power and half of the cylindrical power.[1‐, 3‐, 6‐, and 12‐month after enrolment. ] Anterior chamber depth (ACD) measured at baseline compared to the 1‐, 3‐, 6‐, and 12‐month follow‐up visits. Five measures of ACD will be conducted on each eye prior to cycloplegia using partial coherence interferometry IOLMaster (Carl Zeiss 500, Meditec, Oberkochen, Germany).[1‐, 3‐, 6‐, and 12‐month after enrolment. ] Visual acuity (uncorrected visual acuity (UCVA) and best‐corrected visual acuity (BCVA)) measured at baseline compared to the 1‐, 3‐, 6‐ and 12‐month follow‐up visits. Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) will be assessed at 4 meters by trained optometrists using the Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity chart (Precision Vision, Villa Park, Illinois, USA). The examination protocol is the same as the protocol used in the Refractive Error Study in Children (which was a multi‐country, population‐based study in children organized by the World Health Organization).[1‐, 3‐, 6‐, and 12‐month after enrolment. ] Change in Axial Length (AL) measured at the 1‐, 3‐, 6‐month follow‐up visit compared to baseline. Five measures of AL will be conducted on each eye prior to cycloplegia using partial coherence interferometry IOLMaster (Carl Zeiss 500, Meditec, Oberkochen, Germany) and averaged if the desired precision (i.e., < 0.10 mm) is achieved.[1‐, 3‐, 6‐month after enrolment.] Self‐reported adverse events (AE). A questionnaire specifically designed for this study on adverse events following the intervention will be administered at each follow‐up visit and unexpected visits for the subjects in the intervention group. Subjects and their parents/guardians will be asked about the adverse events, including but not limited to short‐term glare, flash blindness, and afterimages.[1‐, 3‐, 6‐, and 12‐month after enrolment. ] White‐to‐white (WTW) pupil diameter measured at baseline compared to the 1‐, 3‐, 6‐, and 12‐month follow‐up visits. Five measures of ACD will be conducted on each eye prior to cycloplegia using partial coherence interferometry IOLMaster (Carl Zeiss 500, Meditec, Oberkochen, Germany).[1‐, 3‐, 6‐, and 12‐month after enrolment. ]