Repeated low-level red light and ortho-k combined: first European data

Paper title: Repeated low-level red-light therapy combined with orthokeratology for myopia control in Spain: a randomised controlled study

Authors: Fernández Fidalgo MJ (1), Ferigo Ferrel VD (1), Wu Y (2), Qi Z (3), Aung YM (4), Chen Y (5), Zhu Z (6), Fernández-Velázquez FJ (7)

1. Centro Fernández-Velázquez, Madrid, Spain
2. The Hong Kong Polytechnic University, Hong Kong, China
3. Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
4. Eyerising International, Melbourne, Victoria, Australia
5. School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
6. Centre for Eye Research Australia, Ophthalmology, University of Melbourne, Melbourne, Victoria, Australia
7. Centro Fernández-Velázquez, Madrid, Spain

Date: Published online November 20, 2025

Reference: Fernández Fidalgo MJ, Ferigo Ferrel VD, Wu Y, Qi Z, Aung YM, Chen Y, Zhu Z, Fernández-Velázquez FJ. Repeated low-level red-light therapy combined with orthokeratology for myopia control in Spain: a randomised controlled study. Br J Ophthalmol. 2025 Nov 20:bjo-2025-328347. Epub ahead of print.

Link to paper abstract

Orthokeratology (ortho-k) is a commonly used myopia control strategy that reshapes the cornea to slow axial elongation. However, its effectiveness varies across populations, and some children continue to show substantial progression despite treatment. Repeated low-level red-light (RLRL) therapy has recently emerged as another promising intervention, with previous studies in East Asia showing robust efficacy. Given the potential for additive effects, this study sought to evaluate the combination of RLRL and ortho-k in a European population - an area where data has been lacking. 

The purpose of this randomised controlled trial was to determine whether RLRL therapy combined with ortho-k (RCO) could improve myopia control in Spanish children compared to ortho-k alone.

This was a single-site, non-blinded randomised controlled trial involving 26 Spanish children aged 10–13 years with myopia between –0.75 D and –6.75 D. Participants were randomised to receive either ortho-k alone (n=15) or ortho-k plus RLRL therapy (n=11) over a 12-month period. Axial length (AL) was the primary outcome, while macular thickness (MT) was assessed as a secondary outcome. Mean baseline axial lengths were 24.74 mm (ortho-k) and 24.68 mm (RCO), and mean ages were around 12 years in both groups. The RLRL device delivered 650 nm light twice daily, 5 days per week, in 3-minute sessions. 

Key findings were as follows.

1. Mean axial length change over 12 months was –0.124 mm in the RCO group, compared to +0.102 mm in the ortho-k group - a between-group difference of 0.226 mm.
2. Axial shortening of more than –0.05 mm occurred in 80% of children in the RCO group, while no children in the ortho-k group showed axial shortening.
3. AL changes <0.10 mm were seen in all RCO participants, compared to 66.7% in the ortho-k group.
4. No serious adverse events occurred, and all participants maintained BCVA of logMAR ≤0.0 (better than 6/6 or 20/20) at 12 months.
5. Macular thickness increased more in the RCO group than ortho-k, but the difference was not statistically significant at 12 months.

These findings suggest that adding RLRL to ortho-k may be a valuable option for enhancing myopia control. It has previously been shown as useful in Chinese children who show suboptimal response to ortho-k alone - although in this study, the Spanish children were allocated to either ortho-k or the RLRL combination at baseline, and not due to failed monotherapy.

The strong early response - often within the first month - and sustained effect over 12 months offer clinicians a practical strategy for improving myopia control outcomes. This study is also the first to demonstrate efficacy in a European population, supporting the generalisability of RLRL beyond East Asian cohorts.

The absence of adverse events and maintenance of good visual acuity support the safety of this dual-modality approach. Importantly, all children in the RLRL group showed axial elongation of less than 0.10 mm per year - a clinical indicator of highly effective myopia control. This may help inform decisions about escalating therapy in higher-risk cases or those with faster progression. While long-term data are still needed, the short-term benefits suggest this combination may be considered earlier in the treatment course rather than waiting for monotherapy to fail.

This study identified several important limitations. First, the small sample size limits the generalisability of the findings and prevents subgroup analyses that could explore variability in treatment response. While post hoc power calculations suggested sufficient statistical power for the primary outcome of axial length changes, other exploratory comparisons - such as changes in macular thickness - may have been underpowered. Second, the study was conducted at a single site, and although outcome assessors were masked, lack of participant blinding could introduce performance or reporting bias. Third, the 12-month follow-up period is relatively short. The authors note that many myopia control therapies may show strong effects in the first year followed by a plateau; thus, longer-term data are needed to evaluate the durability of the observed axial stability and shortening.

While macular thickness showed no difference between treatment types, choroidal thickness was not assessed in this study, despite its emerging role as an early biomarker of treatment response in both RLRL and ortho-k therapy. The absence of choroidal data limits insights into potential mechanisms underlying the axial length changes observed. Finally, the generalisability of these findings to younger children or those with faster progression is unclear, as the study population was restricted to 10–13-year-old European children with a broad range of baseline myopia. Future studies could include larger, multi-centre cohorts with longer follow-up and additional imaging modalities to validate and extend these findings.

Aim: To evaluate the 12-month efficacy and safety of repeated low-level red-light (RLRL) therapy combined with orthokeratology (ortho-k) (RCO) for controlling myopia in Spanish children.

Methods: In this single-site, randomised, parallel-group, non-blinded clinical trial (NCT06899139), eligible myopic children aged 10–13 years were recruited and assigned randomly either to the RCO group or the ortho-k group. Follow-up assessments were conducted at 6, 9 and 12 months after baseline. The primary outcome and secondary outcome were the axial length (AL) and macular thickness (MT) changes at 12 months estimated by longitudinal mixed model.

Results: All participants (n=26; 11 in the RCO group and 15 in the ortho-k group) were included in the analysis. After 12 months, the adjusted mean AL change was −0.124mm (95%CI −0.164 to −0.084) in the RCO group, whereas the ortho-k group continued to exhibit a modest axial elongation of 0.102mm (95%CI 0.068 to 0.136). The adjusted mean difference in AL change was −0.226mm (95%CI −0.279 to −0.174) between the groups (p<0.001). Additionally, the adjusted mean change in MT showed no significant difference between groups at 12 months. In the RCO group, 80% of children achieved AL shortening >−0.05mm, whereas no children in the ortho-k group showed AL shortening. No severe adverse events were reported during the study.

Conclusions: Combining RLRL therapy with ortho-k is an effective and safe myopia control strategy in Caucasian Spanish children, supporting the potential generalisability of the synergistic effect across diverse ethnic groups.

Link to paper abstract