Real-world Registry Study of Red Light Treatment on Myopia Control: a Focus on Non-responders to Conventional Treatments

Study Centres:

The study data will be contributed by pediatric ophthalmology clinics or optometry clinics in the countries where RLRL therapy has received regulatory approval.

Study Question:

What is the efficacy of repeated low-level red light (RLRL) therapy among children who do not respond to conventional myopia treatments?

INTRODUCTION

Myopia is characterized by progressive axial elongation and loss of distance vision. It is estimated that it will affect half of the world’s population by 2050, 40% of whom are projected to be high myopia [1, 2]. Axial length (AL) elongation is associated with structural and functional alterations in the eye, which increases the risk of vision-threatening conditions such as macular hemorrhage, retinal detachment, cataracts, and glaucoma [3]. Therefore, AL control is an underlying principle for myopia treatment and preventing vision loss [4, 5].

In infant rhesus monkeys, it has been observed that ocular shape is able to recover, to some extent, from experimentally induced myopia once the myopic stimulus is removed [6–10]. After removing the form deprivation and hyperopic defocus stimulus, elongation of the vitreous chamber would slow down, resulting in AL comparable with that of the contralateral eye [7]. This is consolidated by a meta analysis, suggesting eye shortening also takes place in non-human primates following myopic defocus, mainly through modulations in vitreous chamber depth [11]. The eyes of tree shrews had a greater proportion of AL recovery compared with other species in response to myopic defocus [11–18]. This reduces the severity of myopia by increasing spherical equivalent of myopia, and therefore reduces the chances of vision-threatening complications.

In humans, the presence of AL shortening following myopia therapies has only rarely been observed [19, 20]. Repeated low-level red light (RLRL) therapy has  emerged as an innovative and promising approach for the control of myopia progression [21]. We recently reported that the efficacy and safety of RLRL for controlling AL in Chinese children with myopia in a multicenter randomized control trial (RCT), where exposure to RLRL twice daily markedly reduced myopia progression and AL elongation over 1 year [22]. Unexpectedly, a certain proportion of children exhibited AL shortening following RLRL therapy, which is a novel and important finding. Given that the RCT was conducted under strict inclusion and exclusion criteria, the effect of RLRL on AL shortening in real clinical settings with significant population heterogeneity remains unknown. Therefore, a retrospective analysis of RLRL users from 11 hospitals located in six provinces in China were analyzed, with the aim of investigating the 

frequency and associated factors of AL shortening, as well as its associated factors in clinical settings.

Introduction: Myopia is recognized as a progressive eye disease. The aim of this study was to evaluate the frequency and associated factors of clinically significant axial length (AL) shortening among myopic children following repeated low-level red light (RLRL) therapy.

Methods: The clinical data that were collected for the myopic children aged 3–17 years who received an RLRL therapy delivered by home-use desktop light device that emitted light at Version:0.9 StartHTML:0000000105 EndHTML:0000004033 StartFragment:0000000141 EndFragment:0000003993650 nm for at least 1 year, were reviewed. The clinical data included AL, spherical equivalent refraction (SER), and visual acuity measured at baseline and follow-up. The primary outcomes were frequency of AL shortening of [ 0.05 mm, [0.10 mm, and [ 0.20 mm per year, and associated factors of AL shortening per year.

Results: A total of 434 myopic children with at least 12 months of follow-up data were included. The mean age of participants was 9.7 (2.6) years with SER of -3.74 (2.60) diopters. There were 115 (26.50%), 76 (17.51%), and 20 (4.61%) children with AL shortening based on cutoffs of 0.05 mm/year, 0.10 mm/year, and 0.20 mm/ year, respectively. In the multivariable model, AL shortening was signifificantly associated with older baseline age, female gender, and longer baseline AL or greater spherical equivalent refraction (all P \0.05). Among AL shortened eyes, the mean AL difference (standard devia tion, SD) was -0.142 (0.094) mm/year. Greater AL shortening was observed among children who were younger and had longer baseline AL