Efficacy Comparison of Repeated Low-Level Red Light and Low-Dose Atropine for Myopia Control: A Randomized Controlled Trial

Effects of atropine on choroidal hemodynamics and VEGFA and HIF-1α expression in form-deprivation myopia guinea pigs

We investigated the mechanism of action of atropine in myopia control by examining its effect on choroidal hemodynamics. Blood flow was evaluated using indocyanine green (ICG) fluorescence and molecular variation during the development of form-deprivation myopia (FDM) and atropine treatment in guinea pigs. Guinea pigs were divided randomly into the normal control (NC), FDM, and FDM + 1% atropine (ATR) groups, and evaluated by spherical equivalent refractive error (SE) and axial length (AL). Choroidal hemodynamic parameters were measured via ICG fluorescence imaging including the maximal ICG fluorescence intensity (Imax), rising time (Trising), blood flow index (BFI), and mean transit time (MTT). Additionally, the expression in the choroid-RPE complex of choroidal vascular endothelial growth factor A (VEGFA) and HIF-1 α were assessed via Western blotting. Atropine inhibited the development of FDM, with effects of FD on both SE and AL being reduced. ICG fluorescence hemodynamic wide-field maps and time-series curves revealed that the atropine significantly accelerated choroidal blood flow, with reduced Trising and MTT, while increasing Imax, BFI and the number of lobulated choriocapillaris structures compared with the FDM group. In terms of molecular markers, atropine inhibited the effect of FDM, increasing VEGFA levels and reducing HIF-1α expression. These findings suggest that atropine improved choroidal hemodynamics and changed vascular markers, potentially contributing to its role in inhibiting the progression of myopia in the FDM model.

Impact of repeated low-level red-light exposure on choroidal thickness and blood flow in pediatric patients: A SS-OCTA study

PURPOSE

To evaluate the impact of repeated low-level red-light (RLRL) therapy on choroidal thickness and blood flow in pediatric myopia.

METHODS

A three-month trial (April 1, 2023 - September 30, 2023) was conducted involving 44 children (ages 6-16) with myopia. Participants underwent RLRL therapy at home twice daily for five days per week, with each session lasting three minutes. Assessments at baseline, one month, and three months included cycloplegic refraction, best-corrected visual acuity (BCVA), intraocular pressure (IOP), ocular biometrics, swept-source optical coherence tomography angiography (SS-OCTA), slit-lamp, and fundus examinations.

RESULTS

The study included 44 children (average age: 9.79 years; 56.82 % male). RLRL therapy significantly increased subfoveal choroidal thickness (Baseline: 272.82 ± 64.01 μm; 1-month: 297.77 ± 72.94 μm; 3-month: 298.77 ± 77.17 μm, p = 0.001), reduced axial length (Baseline: 24.97 ± 1.47 mm; 3-month: 24.88 ± 1.38 mm, p = 0.002), and showed a marginal regression in spherical equivalent (p = 0.055). Significant elevations in choroidal vessel volume and thickness were noted, with positive correlations intensifying with distance from the fovea.

CONCLUSION

RLRL therapy shows promise in managing pediatric myopia by increasing choroidal vessel volume and thickness, potentially mitigating myopia progression.

Correlation between repeated low-level red light-induced afterimage and axial changes in myopia control

PURPOSE

To explore the correlation between afterimages induced by repeated low-level red light (RLRL) and changes in refraction.

METHOD

Patients who used RLRL for myopia control from 2023.02 to 2024.06 were included in this study. The afterimage appeared on a gray background (RGB 217,217,217; Lab 87,0,0). Afterimage color was recorded with CIELAB nomenclature (R, G, B; L, a, b), and afterimage duration (T) was recorded in seconds. Axial length (AL) and axial length-to-corneal radius ratio (AL/CR) were followed up at 1-, and 3-month. Participants were divided into groups based on a = 0 for GroupR (a>0,red bias in afterimage) and GroupG (a<0,green bias in afterimage); b = 0 for GroupY (b>0,yellow bias in afterimage) and GroupB (b<0,blue bias in afterimage), and T = 50.50 for GroupS (T<50.50,shorter afterimage duration) and GroupL (T>50.50,longer afterimage duration).

RESULTS

A total of 52 participants were included in this study, with an age of 9.25 (1.75) years, 27 (51.92 %) males. The T median (P25, P75) was 50.50 (31.25,85.50) s. After RLRL treatment, divided by a = 0, GroupG showed significantly more shortening in the AL changes than GroupR at 1month and 3months (both P<0.05) and the AL/CR changes difference was not significant. Divided by T = 50.50, GroupS showed significantly greater shortening in the AL changes than GroupL at only 1month (P<0.05) and the AL/CR changes difference was not significant. Divided by b = 0, the difference between GroupY and GroupB was not statistically significant (P>0.05).

CONCLUSION

The change of AL after RLRL treatment showed a correlation to the afterimage. Patients with green afterimage and shorter afterimage duration have a better AL shortening after RLRL treatment. Afterimage may serve as a biomarker for more effective myopia control.

Myopia Control Effect of Repeated Low-Level Red-Light Therapy Combined with Orthokeratology: A Multicenter Randomized Controlled Trial

PURPOSE

To investigate the efficacy and safety of repeated low-level red-light (RLRL) therapy combined with orthokeratology among children who, despite undergoing orthokeratology, exhibited an axial elongation of at least 0.50 mm over 1 year.

DESIGN

Multicenter, randomized, parallel-group, single-blind clinical trial (ClinicaTrials.gov identifier, NCT04722874).

PARTICIPANTS

Eligible children were 8-13 years of age with a cycloplegic spherical equivalent refraction of -1.00 to -5.00 diopters at the initial orthokeratology fitting examination and had annual axial length (AL) elongation of ≥0.50 mm despite undergoing orthokeratology. Forty-eight children were enrolled from March 2021 through January 2022, and the final follow-up was completed in March 2023.

METHODS

Children were assigned randomly to the RLRL therapy combined with orthokeratology (RCO) group or to the orthokeratology group in a 2:1 ratio. The orthokeratology group wore orthokeratology lenses for at least 8 hours per night, whereas the RCO group received daily RLRL therapy twice daily for 3 minutes in addition to orthokeratology.

MAIN OUTCOME MEASURES

The primary outcome was AL change measured at 12 months relative to baseline. The primary analysis was conducted in children who received the assigned intervention and completed at least 1 follow-up after randomization using the modified intention-to-treat principle.

RESULTS

Forty-seven children (97.9%) were included in the analysis (30 in the RCO group and 17 in the orthokeratology group). The mean axial elongation rate before the trial was 0.60 mm/year and 0.61 mm/year in the RCO and orthokeratology groups, respectively. After 12 months, the adjusted mean AL changes were -0.02 mm (95% confidence interval [CI], -0.08 to +0.03 mm) in the RCO group and 0.27 mm (95% CI, 0.19-0.34 mm) in the orthokeratology group. The adjusted mean difference in AL change was -0.29 mm (95% CI, -0.44 to -0.14 mm) between the groups. The percentage of children achieving an uncorrected visual acuity of more than 20/25 was similar in the RCO (64.3%) and orthokeratology (65.5%) groups (P = 0.937).

CONCLUSIONS

Combining RLRL therapy with orthokeratology may offer a promising approach to optimize axial elongation control among children with myopia. This approach also potentially allows children to achieve satisfactory visual acuity, reducing daytime dependence on corrective eyewear.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Safety of repeated low-level red-light therapy for myopia: A systematic review

PURPOSE

Establishing the safety profile of repeated low-level red-light (RLRL) therapy is necessary prior to its widespread clinical implementation.

METHODS

We conducted a systematic review (International Prospective Register of Systematic Reviews, CRD42024516676) of articles across seven databases from inception through February 10, 2024, with keywords related to myopia and RLRL therapy. Pooled safety outcomes and risk-to-benefit ratios were reported, and incidence of side effects was compared with other antimyopia interventions.

RESULTS

Among 689 screened articles, 20 studies (2.90 %; median duration 9 months, longest 24 months) were analysed, encompassing 2380 participants aged 3-18 years and 1436 individuals undergoing RLRL therapy. Two case reports described an identical patient with reversible decline in visual acuity and optical coherence tomography (OCT) abnormalities, completely resolved 4 months after treatment cessation. No cases of permanent vision loss were reported. Temporary afterimage was the most common ocular symptom following treatment, resolving within 6 minutes in reported studies. The number needed to harm outweighed the number needed to treat by a ratio of 12.7-21.4 for a person with -3D to -8D myopia treated with RLRL therapy. Incidence of side effects from RLRL was 0.088 per 100 patient-years (95 % confidence interval, 0.02-0.50).

CONCLUSIONS

No irreversible visual function loss or ocular structural damage was identified with RLRL. Fundus photography and OCT before and during therapy, alongside home monitoring of visual acuity and duration of afterimages, are necessary to identify side effects. Further adequately powered studies of longer duration are needed to evaluate long-term safety of RLRL.

Efficacy comparison of repeated low-level red-light therapy and orthokeratology lenses for myopia control

PURPOSE

This study aimed to compare and analyze the efficacy of repeated low-level red-light therapy and orthokeratology lenses for myopia control in children.

METHODS

Exactly 138 participants were enrolled in this retrospective study. Comprehensive eye examinations were performed prior to treatment. The repeated low-level red-light therapy and orthokeratology lenses groups comprised 67 and 71 patients, respectively. The age range was between 6 and 14 years, with myopia of ≤-0.50 D and astigmatism of ≤2.50 D after cycloplegia. Follow-up data were collected during the initial visit and the treatment period. Changes in axial length over a 2-year period and associated factors were analyzed.

RESULTS

Over the 2-year period, the repeated low-level red-light therapy group exhibited significantly less axial length growth compared with the orthokeratology lenses group (0.17 ± 0.40 vs. 0.50 ± 0.27 mm, p<0.001). In the first year, the axial length growth in the repeated low-level red-light therapy group was significantly less than that in the orthokeratology lenses group (0.03 ± 0.22 vs. 0.28 ± 0.18 mm, p<0.001), with no significant difference observed in the second year (0.14 ± 0.29 vs. 0.21 ± 0.14 mm, p=0.06). The repeated low-level red-light therapy group showed a 55% reduction in axial length after 1 month and a 42% reduction after 1 year, compared with 4% and 3% reductions in the orthokeratology lenses group, respectively. Linear mixed-effects model analysis indicated that the annual axial length change rate in the repeated low-level red-light therapy group was 0.10 mm (95% confidence interval [CI], 0.07 to 0.14), compared with 0.25 mm in the orthokeratology lenses group (95% CI, 0.24 to 0.27), with an average difference of 0.15 mm (95% CI, -0.17 to -0.12, p<0.001).

CONCLUSIONS

Repeated low-level red-light therapy demonstrated slightly superior efficacy in controlling myopia progression in children compared with orthokeratology lenses.

Axial Shortening Effects of Repeated Low-level Red-light Therapy in Children With High Myopia: A Multicenter Randomized Controlled Trial

PURPOSE

To evaluate the effectiveness and safety of repeated low-level red-light (RLRL) in delaying the progression of high myopes with -6.00 diopters (D) or worse.

DESIGN

Multicenter, randomized, parallel-group, single-blind clinical trial. A total of 202 high myopic children aged 7 to 12 years with cycloplegia spherical equivalent (SE) refraction ≤-6.00 D, astigmatism less than 2.50 D, and anisometropia of 1.50 D or less were enrolled from March 2022 to December 2022. Follow-up was completed in December 2023.

METHODS

Eligible participants were randomly allocated to the intervention (RLRL + single vision spectacle) or the control group (single vision spectacle). The RLRL treatment was administered every day for 3 minutes, twice a day, with an interval of at least 4 hours. The primary outcome was the change in axial length (AL) at 12 months compared with baseline. Secondary outcomes included changes in SE, changes in choroidal thickness (ChT), and changes in retinal thickness (RT) in different circle sectors. Outcomes were analyzed by means of intention-to-treat and per-protocol methods.

RESULTS

After 12 months of treatment, AL and SE changes were -0.11 ± 0.25 mm and 0.18 ± 0.63 D for the RLRL group and 0.32 ± 0.09 mm and -0.80 ± 0.42 D for the control group, respectively. Axial shortening >0.05 mm was 59% in the RLRL and 0% in the control group at 12 months. ChT and RT from a single center were analyzed. In the RLRL group, ChT was thickened in all sectors at 12 months. RT was increased in parafoveal and perifoveal circles. In the control group, all sectors of ChT and only perifoveal RT were significantly thinner at 12 months. The multivariate linear regression model revealed significant correlations between changes in the ChT central foveal circle and RT perifoveal circle at 1 month and AL changes at 12 months. No fundus structure changes, afterimage exceeding 6 minutes, or best-corrected visual acuity decrease were reported.

CONCLUSIONS

RLRL could effectively shorten the AL and inhibit the progression of myopia in high myopic patients with -6.00 D or worse. AL shortening is sustained over 12 months of treatment. These observed changes appeared to be associated with increases in ChT and RT.

The Effect of Repeated Low-Level Red-Light Therapy on Myopia Control and Choroid

Purpose

To investigate the long-term effects of repeated low-level red light (RLRL) therapy on the axial length (AL), spherical equivalent (SE), and choroidal parameters.

Methods

Two hundred eight myopic eyes were recruited. The RLRL group included 100 eyes, whereas the control group included 108 eyes. Throughout the one-year follow-up period, changes in AL and SE were recorded for both groups. The RLRL group underwent additional choroidal imaging, and changes in choroidal thickness (CT), choroidal vascularity (CV), and choriocapillaris luminal area (CLA) were assessed before and after RLRL therapy.

Results

During the follow-up period, the changing trends in AL and SE differed significantly between the RLRL and control groups. In the RLRL group, AL decreased at three and six months (both P < 0.05) and returned to pretreatment values at 12 months (P = 0.453). In contrast, AL increased significantly throughout the follow-up period (three, six, and 12 months) in the control group (all P < 0.001). The SE increased significantly during the entire follow-up period in the RLRL group (all P < 0.001), whereas it decreased significantly in the control group (all P < 0.05). Regarding choroidal parameters, significant improvements were observed in CT, CV and CLA throughout the follow-up period (all P < 0.05), and changes in most choroidal parameters were significantly correlated with changes in AL and SE during the follow-up period (all P < 0.05). Furthermore, AL, SE, and most choroidal parameters showed significant correlations between changes at three and 12 months (all P < 0.05).

Conclusions

RLRL therapy significantly improved choroidal blood perfusion and circulation, which may explain the observed slowing or reversal of myopia progression in the RLRL group. Thus RLRL therapy may be a novel and effective method for controlling myopia. Furthermore, the short-term effect of photobiomodulation therapy (i.e., changes at three months) can be used to predict the long-term effects (i.e., changes at 12 months).

Translational Relevance

In this study, RLRL therapy showed a significant control effect on the development of axial length and spherical equivalent. RLRL therapy also promoted the choroidal blood perfusion and circulation. RLRL therapy could be a novel and effective method for myopia control.

Effectiveness of low-level red light for controlling progression of Myopia in children and adolescents

OBJECTIVE

To evaluate the effectiveness of low-level red light (LRL) in controlling the progression of myopia in children and adolescents.

METHODS

A randomized controlled trial was conducted from March 2022 to June 2022 at the Xuzhou First People's Hospital. A total of 73 children and adolescents with myopia, between the ages of 6 and 14, and meeting the inclusion criteria, were randomly divided into two groups. The experimental group wore single vision spectacles with LRL intervention, while the control group wore single vision spectacles alone. Spherical equivalent refraction (SER), axial length (AL), subfoveal choroidal thickness (SFCT), and best-corrected visual acuity (BCVA) were measured for the participants. Data analysis was performed using chi-square test, independent samples t-test, and Mann-Whitney U test. To compare the changes in SER and AL between groups, we utilized the Generalized Estimating Equations (GEE) model.

RESULTS

The experimental group was composed of 36 individuals, while the control group had 37. The mean age of the participants was 8.9 ± 2.0 years. No statistically significant distinctions in SER, AL and SFCT were observed between the two groups at baseline (P > 0.05). After 6 months of intervention, the experimental group's increase in SER (-0.01D; 95 % CI: -0.09, 0.06) was higher than that of the control group (-0.41D; 95 % CI: -0.51, -0.32), with a significance level of P < 0.001. Furthermore, the changes over time revealed significant differences between the two groups (Wald χ2group×time: 31.576, P < 0.001). The experimental group's AL increase (-0.02 mm; 95 % CI: -0.07, 0.03) was less than the control group's (0.22 mm; 95 % CI: 0.19, 0.25) (P < 0.001), with a significant difference over time between them (wald χ2group×time: 62.305, P < 0.001). SFCT change after 6 months in the experimental group was significantly greater (29.19 μm; 95 % CI: 18.48, 39.91) compared to that of the control group (-6.59 μm; 95 % CI: -14.28, 1.09) (P < 0.001). No adverse events were observed, and there was no evidence of fundus structural damage on OCT imaging.

CONCLUSIONS

The findings suggest that low-level red light can effectively control myopia progression in children and adolescents within 6 months. No adverse reactions were observed.

Efficacy of repeated low-level red-light therapy combined with optical lenses for myopia control in children and adolescents

PURPOSE

To evaluate the efficacy of repeated low-level red-light (RLRL) therapy combined with optical lenses in children and adolescents with myopia.

METHODS

This retrospective study included 108 children and adolescents. Based on the difference in the combination intervention scheme participants were divided into four groups based on the intervention they received: the RLRL+orthokeratology (OK) lens intervention group (RLRL+OK group), the RLRL+defocus distributed multi-point (DDM) lens intervention group (RLRL+DDM group), the RLRL+single-vision spectacles (SVS) intervention group (RLRL+SVS group), and a control group. Visual acuity, spherical equivalent refraction (SER), and axial length (AL) were measured before and after the intervention. Binary logistic regression was used to identify factors influencing vision recovery.

RESULTS

The SER and AL at baseline were statistically different (P<0.01). After the intervention, the AL increase in the RLRL+OK, RLRL+DDM, and RLRL+SVS groups was significantly better than the control group across time points (P<0.001). Changes in SER were also statistically significant in the RLRL+DDM and RLRL+SVS groups compared to the control group across time points (P<0.001). The intervention method was identified as a significant factor influencing vision recovery (P<0.001).

CONCLUSION

RLRL therapy combined with optical lenses is effective in controlling myopia progression in children and adolescents.

Effectiveness of repeated low-level red light in myopia prevention and myopia control

BACKGROUND/AIMS

To compare the effects of repeated low-level red light (RLRL) treatment on axial length growth and refractive error changes in myopic and premyopic children.

METHODS

Subjects were assigned randomly to four subgroups: myopia-RLRL group (M-RL), myopia-control group (M-C), premyopia-RLRL group (PM-RL) and premyopia-control group (PM-C). Subjects in the RLRL group completed a 12-month treatment composed of a 3 min RLRL treatment session twice daily, with an interval of at least 4 hours, for 7 days per week. Visits were scheduled before and at 1-month, 3-month, 6-month, 9-month and 12-month follow-up after the treatment. Repeated-measures analysis of variance was used to compare the spherical equivalent refractive errors (SE) and axial length (AL) changes between the groups across the treatment period.

RESULTS

After 12 months of treatment, in the myopia group, SE and AL changes were -0.078±0.375 D and 0.033±0.123 mm for M-RL and -0.861±0.556 D and 0.415±0.171 mm for M-C; in the premyopia group, the progression of SE and AL was -0.181±0.417 D and 0.145±0.175 mm for PM-RL and -0.521±0.436 D and 0.292±0.128 mm for PM-C. PM-RL indicated a lower myopia incidence than PM-C (2.5% vs 19.4%). Additionally, the percentage of AL shortening in the M-RL was higher than that in the PM-RL before the 9-month follow-up.

CONCLUSION

RLRL effectively delayed myopia progression in children with myopia and reduced the incidence of myopia in premyopic children. Moreover, RLRL exhibited a stronger impact on myopic children compared with premyopic individuals.

L. S, Jeong J, Saw SM, Sevdalis N, Najjar RP. Light Therapy for Myopia Prevention and Control: A Systematic Review on Effectiveness, Safety, and Implementation

Purpose

This systematic review focuses on the effectiveness, safety, and implementation outcomes of light therapy as an intervention to prevent or control myopia in children.

Methods

A systematic literature search was performed in PubMed, EMBASE, CINAHL, SCOPUS, and Web of Science up to January 27, 2024. Effectiveness outcomes included myopia incidence, and changes in axial length (AL), spherical equivalent refraction (SER), and choroidal thickness (CT). Safety outcomes relating to retinal health or damage and implementation outcomes including compliance rates and loss to follow-up were extracted. ROBINS-I, ROB 2, and ROB-2 CRT were used to assess risk of bias.

Results

Nineteen interventional studies were included. Increased outdoor time (n = 3), red-light therapy (n = 13), and increased classroom lighting (n = 1) had a significant effect on myopia incidence, and changes in AL, SER, and CT. Violet-light therapy (n = 2) was only effective in children aged 8 to 10 years and children without eyeglasses with less than 180 minutes of near-work time daily. Two studies using red-light therapy reported adverse effects. For all studies, only compliance rates and loss to follow-up were reported on implementation effectiveness.

Conclusions

Evidence is compelling for the effectiveness of red-light therapy and outdoors time; more data are needed to confirm safety. Robust data are still needed to prove the effectiveness of violet-light and increased classroom lighting. Clearer implementation strategies are needed for all light therapies.

Translational Relevance

Light therapy has emerged as effective for myopia prevention and control. This systematic review summarizes the state of knowledge and highlights gaps in safety and implementation for these strategies.

The efficacy and safety of combination therapy of repeated low-level red light and defocus-incorporated multiple segments spectacle lenses for myopia control in children: the study protocol for a 12-month, randomized, parallel-controlled, and single-center clinical trial

BACKGROUND

Myopia is increasing in prevalence worldwide. Combination therapy showed a better effect on myopia control than monotherapy. Repeated low-level red light therapy (RLRL) therapy and defocus-incorporated multiple segment (DIMS) spectacle lenses have been reported to retard myopia progression significantly. However, whether these two therapies are better than one is still unknown. The present study aims to report the study protocol of a trial designed to evaluate the efficacy and safety of combination therapy of RLRL and DIMS versus DIMS alone for reducing the progression of myopia among Chinese school-aged children.

METHODS

This study is a 12-month, randomized, parallel-controlled, single-center clinical trial. We will recruit children aged 8-12 years with spherical equivalence (SE) between - 0.50 D and - 6.00 D under cycloplegia in both eyes. We will recruit 66 participants with an allocation ratio of 1:1 from our hospital. Participants in the intervention group will be treated with an RLRL therapy device twice a day from Monday to Friday at home, 3 min per session, with a minimum interval of 4 h, under the supervision of their parents/guardians. They will wear DIMS spectacles for myopia correction during the day. Participants in the control group will not receive the RLRL therapy and will only wear DIMS spectacles to correct myopia. Participants from both groups will attend the hospital every 6 months. The primary outcome is the change in axial length at 12 months. Secondary outcomes include changes in refraction under cycloplegia, optical coherence tomography (OCT), multifocal electroretinogram (mfERG), color vision, and participants' self-reporting of adverse events at 12 months.

DISCUSSION

This study will report the efficacy and safety outcome of the combination therapy of RLRL and DIMS versus DIMS for school-aged children with myopia in detail.

TRIAL REGISTRATION

ChiCTR2300075398. Registered 4 September 2023. https://www.chictr.org.cn/bin/project/edit?pid=200751 .

Effects of short-term exposure to red or near-infrared light on axial length in young human subjects

PURPOSE

To determine whether visible light is needed to elicit axial eye shortening by exposure to long wavelength light.

METHODS

Incoherent narrow-band red (620 ± 10 nm) or near-infrared (NIR, 875 ± 30 nm) light was generated by an array of light-emitting diodes (LEDs) and projected monocularly in 17 myopic and 13 non-myopic subjects for 10 min. The fellow eye was occluded. Light sources were positioned 50 cm from the eye in a dark room. Axial length (AL) was measured before and after the exposure using low-coherence interferometry.

RESULTS

Non-myopic subjects responded to red light with significant eye shortening, while NIR light induced minor axial elongation (-13.3 ± 17.3 μm vs. +6.5 ± 11.6 μm, respectively, p = 0.005). Only 41% of the myopic subjects responded to red light exposure with a decrease in AL and changes were therefore, on average, not significantly different from those observed with NIR light (+0.2 ± 12.1 μm vs. +1.1 ± 11.2 μm, respectively, p = 0.83). Interestingly, there was a significant correlation between refractive error and induced changes in AL after exposure to NIR light in myopic eyes (r(15) = -0.52, p = 0.03) and induced changes in AL after exposure to red light in non-myopic eyes (r(11) = 0.62, p = 0.02), with more induced axial elongation with increasing refractive error.

CONCLUSIONS

Incoherent narrow-band red light at 620 nm induced axial shortening in 77% of non-myopic and 41% of myopic eyes. NIR light did not induce any significant changes in AL in either refractive group, suggesting that the beneficial effect of red laser light therapy on myopia progression requires visible stimulation and not simply thermal energy.

Efficacy of repeated low-level red-light therapy in the prevention and control of myopia in children

OBJECTIVE

In this study, we aimed to determine how different factors influence the effectiveness of repeated low-level red-light (RLRL) therapy in preventing and treating myopia in children.

METHODS

Between June 2022 and April 2023, 336 children who visited our hospital due to myopia or significant decreases in hyperopia reserve were enrolled. The children were treated twice daily for three minutes with a head-mounted low-level red-light (single wavelength of 650 nm) therapeutic device. Each of the two treatment sessions was separated by at least four hours. The axial lengths and diopters of the children's eyes were compared before and three months after treatment, and the effects of gender, age, and baseline diopter on the efficacy of RLRL therapy were analyzed.

RESULTS

Following three months of treatment, the average axial length of the eyes decreased by 0.031 mm. The condition was better for the boys than for girls, but the difference was not statistically significant. As age increased (F = 8.112, P = 0.000) or as the absolute value of baseline myopia degree increased (F = 10.51, P = 0.000), axial lengths of the eyes tended to decrease. The spherical equivalent refraction (SER) of children decreased by an average of 0.012 ± 0.355D. The condition was better for the boys than for girls, but the difference was not statistically significant. SER increased in the direction of hyperopic drift as age increased (F = 2.48, P = 0.031), or as the absolute value of baseline myopia degrees increased (F = 6.835, P = 0.000). There were no obvious side effects following the treatment.

CONCLUSION

This study showed that RLRL therapy is a potential efficient, easily operable, and practically feasible method for the prevention and control of myopia.

Safety of repeated low-level red-light therapy for children with myopia

BACKGROUD

To investigate the safety of repetitive low-level red-light therapy (RLRLT) in children with myopia.

METHODS

Children with myopia were assigned to the RLRL and control groups. Axial length (AL) and spherical equivalent refraction (SER) were followed up at 3-, 6-, and 12-month. To evaluate the safety of RLRLT, at 6 and 12 months in the RLRL group, multifocal electroretinography (mfERG) and contrast sensitivity were recorded. Furthermore, optical coherence tomography was used to measure the relative reflectance of the ellipsoid zone (rEZR), photoreceptor outer segment (rPOSR), and retinal pigment epithelium (rRPER).

RESULTS

A total of 108 children completed the trial (55 in the RLRL group and 53 in the control group). After 3, 6, and 12 months, AL was shorter and SER less myopic in the RLRL group than in the control group. Regarding the safety of the RLRLT, the response density and amplitude of the P1 wave of the first ring of the mfERG increased significantly at 6 months (P = 0.001 and P = 0.017, respectively). At 6 and 12 months, contrast sensitivity at the high spatial frequency increased. Moreover, the rEZR increased significantly at 6 months (P = 0.029), the rPOSR increased significantly at 6 and 12 months (both P < 0.001), and the increase in rPOSR was greater with greater AL regression.

CONCLUSIONS

Based on retinal function and structure follow-up, RLRLT was safe within 12 months. However, rEZR and rPOSR increased, the effects of this phenomenon requires further observation.

Daily Low-Level Red Light for Spherical Equivalent Error and Axial Length in Children With Myopia: A Randomized Clinical Trial

Importance

Treatments are needed to slow progression of or reduce incidence of myopia.

Objective

To evaluate the efficacy and safety of daily 650-nm low-level red light (LLRL) for myopia treatment.

Design, Setting, and Participants

Single-masked, randomized clinical trial at 1 site in China. Baseline measurements were completed from August to September 2021. Participants were children aged 6 to 12 years with spherical equivalent error (SER) of -6 diopters (D) to 3 D. Data were analyzed from March to July 2023.

Interventions

Irradiation daily with 650-nm LLRL for 3 minutes twice daily 4 or more hours apart or no intervention.

Main Outcomes and Measures

Primary outcomes were changes in cycloplegia SER and axial length (AL) at 6- and 12-month follow-up visits. Safety was assessed on masked fundus photograph evaluations.

Results

A total of 336 children were randomly allocated into the LLRL group or control group in a 1:1 ratio. The control group contained 86 female patients (51.2%), and the treatment group contained 90 female patients (53.6%). The mean (SD) age, SER, and AL were 9.0 (1.9) years, -1.3 (1.5) D, and 23.8 (1.0) mm for all patients. A total of 161 (95.8%) in the LLRL group and 159 (94.6%) in the control group returned for the 6-month follow-up. A total of 157 (93.5%) in the LLRL group and 152 (90.5%) in the control group returned for the 12-month follow-up. Mean (SD) changes in SER were 0.15 (0.16) D and -0.26 (0.21) D for the LLRL group and the control group, respectively (difference, -0.41 D; 95% CI, -0.48 to -0.34 D; P < .001), at 6 months and 0.24 (0.27) D and -0.65 (0.33) D for the LLRL group and the control group, respectively (difference, -0.89 D; 95% CI, -0.95 to -0.83 D; P < .001), at 12 months. Mean (SD) changes in AL were -0.06 (0.08) mm and 0.13 (0.12) mm for the LLRL group and control group, respectively (difference, 0.19 mm; 95% CI, 0.16 to 0.22 mm; P < .001), at 6 months and -0.11 (0.10) mm and 0.26 (0.16) mm for the LLRL group and control group, respectively (difference, 0.37 mm; 95% CI, 0.34 to 0.40 mm; P < .001). Masked fundus photograph review did not identify retinal changes in either group.

Conclusions and relevance

These findings suggest daily use of 650-nm LLRL for 1 year can slow progression of SER and AL without safety concerns identified. Confirmation of these findings at independent sites seems warranted, as well as determining whether these effects can be sustained with or without continued treatment and whether LLRL has any effect on pathological myopia.

Trial Registration

ChiCTR2200058963.

Low-level red-light therapy for myopia control in children: A systematic review and meta-analysis

INTRODUCTION

Low-Level Red-Light (LLRL) Therapy is a safe and natural way to promote healing and reduce inflammation in the body. When it comes to treating myopia in children, LLRL therapy is recent, and its efficacy and safety still are not clear.

METHODS

A systematic review and meta-analysis of the literature for LLRL was conducted in accordance with the PRISMA guidelines on November 5, 2022. Databases, including PUBMED, Cochrane Library, Web of Science, and Embase were queried. A meta-analysis of random effects was conducted. Inclusion criteria included Randomized Controlled Trials (RCTs) or observational studies where LLRL therapy was used in children (3‒15 years old) with myopia. Exclusion criteria were studies with other ocular abnormalities. Efficacy was evaluated through the mean change in Axial Length (AL) and cycloplegic Spherical Equivalent Error (SER), while safety was evaluated by monitoring adverse effects.

RESULTS

A total of 5 final studies were included (4 RCTs, and 1 observational), in which 685 total patients were analyzed. The mean age was 9.7 ± 0.66 years, with 48,2% female patients. The number of eyes in the LRLL arm is 714 and, in the control, arm is 656. LLRL showed better results in SER and AL mean change (OR = 0.58; 95% CI 0.33 to 0.83; p < 0.00001, and MD -0.33; 95% CI -0.52 to -0.13; p = 0.001, respectively), in comparison to the control group. There was no significant difference in adverse effects between groups (MD = 5.76; 95% CI 0.66 to 50.14; p = 0.11).

CONCLUSION

LLRL therapy is a non-invasive, effective, and safe short-term treatment option; however, long-term evaluation, particularly in comparison to other therapies, requires additional investigation.

Repeatability and agreement of the MYAH and Lenstar

SIGNIFICANCE

Validation of new biometry instruments against the gold standard and establishing repeatability are important before being utilized for clinical and research applications.

PURPOSE

This study aimed to investigate intersession repeatability of the MYAH optical biometer and corneal topographer and examine agreement with the Lenstar LS900 optical biometer in healthy young adults.

METHODS

Forty participants (mean age, 25.2 ± 3.1 years) presented for two visits, 2 to 4 days apart. At each visit, measurements for right eyes were collected with the MYAH and Lenstar LS 900 and included axial length, corneal power, white-to-white distance, and pupil diameter. Bland-Altman analysis was used to assess the intrasession agreement between the MYAH and Lenstar for each parameter and intersession repeatability for the two devices. For each device, coefficient of variation and intraclass correlation coefficient were calculated, and paired t tests between visits were performed to assess intersession repeatability.

RESULTS

Good agreement (mean difference [95% limits of agreement]) between the MYAH and Lenstar was found for axial length (-0.01 [-0.07 to 0.04] mm), corneal power (-0.02 D [-0.15 to 0.19 d]), white-to-white distance (-0.13 [-0.43 to 0.17] mm), and pupil diameter (-0.27 [-0.79 to 1.33] mm). The limits of agreement, coefficient of variations, and intraclass correlation coefficients for MYAH-measured parameters were -0.04 to 0.04, 0.06%, and >0.99 for axial length; -0.24 to 0.19, 0.18%, and >0.99 for corneal power; -1.05 to 1.15, 0.57%, and 0.96 for white-to-white distance; and -0.17 to 0.21, 7.0%, and 0.76 for pupil diameter, with no significant difference between visits (p>0.05 for all), indicating good intersession repeatability. Similar intersession repeatability was also noted for Lenstar.

CONCLUSIONS

Findings show good intersession repeatability of the MYAH and good agreement with the Lenstar for axial length, corneal power, and white-to-white distance in young adults. Pupil diameter was more variable, likely due to the dynamic nature of the pupil. This study provides validation and supports the use of the MYAH for ocular biometry.

Red light instruments for myopia exceed safety limits

PURPOSE

Low-level red light (LLRL) therapy has recently emerged as a myopia treatment in children, with several studies reporting significant reduction in axial elongation and myopia progression. The goal of this study was to characterise the output and determine the thermal and photochemical maximum permissible exposure (MPE) of LLRL devices for myopia control.

METHODS

Two LLRL devices, a Sky-n1201a and a Future Vision, were examined. Optical power measurements were made using an integrating sphere radiometer through a 7-mm diameter aperture, in accordance with ANSI Z136.1-2014, sections 3.2.3-3.2.4. Retinal spot sizes of the devices were obtained using a model eye and high-resolution beam profiler. Corneal irradiance, retinal irradiance and MPE were calculated for an eye positioned at the oculars of each device.

RESULTS

Both devices were confirmed to be Class 1 laser products. Findings showed that the Sky-n1201a delivers laser light as a point source with a 654-nm wavelength, 0.2 mW power (Ø 7 mm aperture, 10-cm distance), 1.17 mW/cm2 corneal irradiance and 7.2 W/cm2 retinal irradiance (Ø 2 mm pupil). The MPE for photochemical damage is 0.55-7.0 s for 2-7 mm pupils and for thermal damage is 0.41-10 s for 4.25-7 mm pupils. Future Vision delivers the laser as an extended source subtending 0.75 × 0.325°. It has a 652-nm wavelength, 0.06 mW power (Ø 7 mm aperture, 10 cm distance), 0.624 mW/cm2 corneal irradiance and 0.08 W/cm2 retinal irradiance (Ø 2 mm pupil). MPE for photochemical damage is 50-625 s for 2-7 mm pupils.

DISCUSSION

For both of the LLRL devices evaluated here, 3 min of continuous viewing approached or surpassed the MPE, putting the retina at risk of photochemical and thermal damage. Clinicians should be cautious with the use of LLRL therapy for myopia in children until safety standards can be confirmed.

Scleral collagen cross linkage in progressive myopia

High myopia is often associated with local ectasia and scleral thinning. The progression of myopia depends upon scleral biochemical and biomechanical properties. Scleral thinning is associated with decreased collagen fiber diameter, defective collagen fibrillogenesis, and collagen cross-linking. Reversing these abnormalities may make the sclera tougher and might serve as a treatment option for myopic progression. Collagen cross-linking is a natural process in the cornea and sclera, which makes the structure stiff. Exogenous collagen cross-linkage is artificially induced with the help of external mediators by using light and dark methods. In this systematic review, we discussed existing literature available on the internet on current evidence-based applications of scleral collagen cross-linking (SXL) by using different interventions. In addition, we compared them in tabular form in terms of their technique, mechanisms, cytotoxicity, and the stage of transition from preclinical to clinical development. Furthermore, we discussed the in-vivo technique to evaluate the post-SXL scleral biomechanical property and outcome in the human eye.

Treatment of Rapid Progression of Myopia: Topical Atropine 0.05% and MF60 Contact Lenses

This retrospective study evaluates the effectiveness of combining 0.05% atropine with MF60 contact lenses in managing rapid myopia progression in children over one year. The study involved three groups: the treatment group (TG) with 15 children (53% male, average age 12.9 ± 1.04), the MF group (MF) with 12 children (50% male, average age 12.8 ± 0.8) using only MF60 lenses, and the control group (CG) with 14 children (43% male, average age 12.1 ± 0.76). Baseline myopia and axial length (AL) were similar across groups, with the TG, MF, and CG showing -4.02 ± 0.70 D, -4.18 ± 0.89 D, -3.86 ± 0.99 D, and 24.72 ± 0.73 mm, 24.98 ± 0.70 mm, 24.59 ± 1.02 mm, respectively. Prior to the study, all groups exhibited significant myopia and AL progression, with no previous myopia control management. The treatment involved daily 0.05% atropine instillation, the use of MF60 lenses and increased outdoor activity. Biannual cycloplegic refraction and slit lamp evaluations confirmed no adverse reactions. After one year, the TG showed a significant reduction in myopia and AL progression (-0.43 ± 0.46 D, p < 0.01; 0.22 ± 0.23 mm, p < 0.01), whereas the CG showed minimal change (-1.30 ± 0.43 D, p = 0.36; 0.65 ± 0.35 mm, p = 0.533). The MF group also exhibited a notable decrease (-0.74 ± 0.45 D, p < 0.01; 0.36 ± 0.23 mm). Increased outdoor activity during the treatment year did not significantly impact myopia control, suggesting its limited additional effect in this cohort. The study concludes that the combination of 0.05% atropine and peripheral defocus soft contact lenses effectively controls myopia progression in children.

Efficacy of Different Powers of Low-Level Red Light in Children for Myopia Control

PURPOSE

To compare the efficacy and safety of low-level red light (LRL) in controlling myopia progression at 3 different powers: 0.37 mW, 0.60 mW, and 1.20 mW.

DESIGN

Single-center, single-masked, randomized controlled trial.

PARTICIPANTS

Two hundred children aged 6-15 with myopia of -0.50 diopter (D) or more and astigmatism of -2.50 D or less were enrolled from April to May 2022. Follow-up ended in December 2022.

METHODS

Participants were assigned randomly to 3 intervention groups and 1 control group (1:1:1:1). All participants wore single-vision spectacles. Moreover, the intervention group randomly received LRL at 3 different powers twice daily for 3 minutes per session, with a minimum 4-hour interval.

MAIN OUTCOME MEASURES

Changes in spherical equivalent (SE), axial length (AL), and subfoveal choroidal thickness (SFCT) were measured.

RESULTS

After 6 months, SE progression was significantly lower in the 0.37-mW group (0.01 D; 95% confidence interval [CI], -0.12 to 0.15), 0.60-mW group (-0.05 D; 95% CI, -0.18 to 0.07), and 1.20-mW group (0.16 D; 95% CI, 0.03 to 0.30) compared to the control group (-0.22 D; 95% CI, -0.50 to 0.30; adjusted P < 0.001 for all). AL changes in the 0.37-mW group (0.04 mm; 95% CI, -0.01 to 0.08), 0.60-mW group (0.00 mm; 95% CI, -0.05 to 0.05), and 1.20-mW group (-0.04 mm; 95% CI, -0.08 to 0.01) were significantly smaller than the control group (0.27 mm; 95% CI, 0.22 to 0.33; adjusted P < 0.001 for all). Similarly, increases in SFCT were significantly greater in the 0.37-mW group (22.63 μm; 95% CI, 12.13 to 33.34 μm), 0.60-mW group (36.17 μm; 95% CI, 24.37 to 48.25 μm), and 1.20-mW group (42.59 μm; 95% CI, 23.43 to 66.24 μm) than the control group (-5.07 μm; 95% CI, -10.32 to -0.13 μm; adjusted P < 0.001 for all). No adverse events were observed.

CONCLUSIONS

LRL effectively controlled myopia progression at 0.37 mW, 0.60 mW, and 1.20 mW. Further research is required.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Repeated Low-level Red-light Therapy: The Next Wave in Myopia Management?

SIGNIFICANCE

Exposure to long-wavelength light has been proposed as a potential intervention to slow myopia progression in children. This article provides an evidence-based review of the safety and myopia control efficacy of red light and discusses the potential mechanisms by which red light may work to slow childhood myopia progression.The spectral composition of the ambient light in the visual environment has powerful effects on eye growth and refractive development. Studies in mammalian and primate animal models (macaque monkeys and tree shrews) have shown that daily exposure to long-wavelength (red or amber) light promotes slower eye growth and hyperopia development and inhibits myopia induced by form deprivation or minus lens wear. Consistent with these results, several recent randomized controlled clinical trials in Chinese children have demonstrated that exposure to red light for 3 minutes twice a day significantly reduces myopia progression and axial elongation. These findings have collectively provided strong evidence for the potential of using red light as a myopia control intervention in clinical practice. However, several questions remain unanswered. In this article, we review the current evidence on the safety and efficacy of red light as a myopia control intervention, describe potential mechanisms, and discuss some key unresolved issues that require consideration before red light can be broadly translated into myopia control in children.

Preventing the Progression of Myopia in Children-A Review of the Past Decade

The growing incidence of myopia worldwide justifies the search for efficient methods of myopia prevention. Numerous pharmacological, optical, and lifestyle measures have already been utilized, but there remains a need to explore more practical and predictable methods for myopia control. This paper presents a review of the most recent studies on the prevention of myopia progression using defocus-incorporated multiple-segment spectacle lenses (DIMSsl), repeated low-level red-light (RLRL) therapy, and a combination of low-dose atropine (0.01%) with orthokeratology lenses.

Repeated Low-Level Red Light Therapy for the Control of Myopia in Children: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Repeated low-level red light (RLRL) therapy has been suggested to be effective in children with myopia. However, evidence from randomized controlled trials (RCTs) is still limited. We performed a meta-analysis of RCTs to systematically evaluate the efficacy of RLRL on changes of axial length (AL) and cycloplegic spherical equivalent refraction (SER) in children with myopia.

METHODS

Relevant RCTs were obtained through a search of electronic databases including PubMed, Embase, Cochrane Library, Wanfang, and China National Knowledge Infrastructure from inception to September 15, 2022. A random-effects model was used to pool the results after incorporating the influence of potential heterogeneity. Subgroup analyses were performed according to the control treatment and follow-up duration.

RESULTS

A total of seven RCTs involving 1,031 children with myopia, aged 6 to 16 years, were included in the meta-analysis. Compared with control treatment without RLRL, treatment with RLRL was associated with a significantly reduced AL (mean difference [MD]: -0.25 mm, 95% confidence interval [CI]: -0.32 to -0.17, P <0.001; I 2 =13%) and a significantly increased cycloplegic SER (MD: 0.60 D, 95% CI: 0.44-0.76, P <0.001; I 2 =20%). Further subgroup analyses showed consistent results in studies comparing children wearing single vision lenses and those receiving active treatment including orthokeratology or low-dose atropine eye drops, as well as studies of treatment duration of 6 and 12 months.

CONCLUSIONS

Results of the meta-analysis suggested that RLRL treatment is effective for slowing down the progression of myopia in children aged 6 to 16 years.

Efficacy of Repeated Low-Level Red-Light Therapy for Slowing the Progression of Childhood Myopia: A Systematic Review and Meta-analysis

PURPOSE

To evaluate the long-term efficacy and safety of repeated low-intensity red light (RLRL) treatment for childhood myopia.

DESIGN

Systematic review and meta-analysis METHODS: We searched PubMed, Web of Science, CNKI, and Wanfang from inception to February 8, 2023. We used the RoB 2.0 and ROBINS-I tools to assess the risk of bias and then used a random-effect model to calculate the weighted mean difference (WMD) and 95% CIs. The primary outcomes were WMD in spherical equivalent refractive error (SER), WMD in axial length (AL), and WMD in subfoveal choroid thickness (SFChT). Subgroup analyses were performed to investigate the sources of heterogeneity based on variation in follow-up and study design. The Egger and Begg tests were used to assess publication bias. Sensitivity analysis was used to verify the stability.

RESULTS

This analysis included 13 studies (8 randomized controlled trials, 3 non-randomized controlled trials, and 2 cohort studies) involving 1857 children and adolescents. Eight studies met the meta-analysis criteria, and the WMD for myopia progression between RLRL and the control group was 0.68 diopters (D) per 6 months (95% CI = 0.38 to 0.97 D; I2 = 97.7%; P < .001) for SER change; -0.35 mm per 6 months (95% CI = -0.51 to -0.19 mm; I2 = 98.0%; P < .001) for AL elongation; and 36.04 µm per 6 months (95% CI = 19.61 to 52.48 µm; I2 = 89.6%; P < .001) for SFChT change.

CONCLUSIONS

Our meta-analysis shows that RLRL therapy may be effective for delaying the progression of myopia. The evidence is low certainty, and larger and better randomized clinical trials with 2-year follow-ups are needed to improve the existing state of knowledge to inform medical guidelines more comprehensively.

Longitudinal Changes in Choroidal Structure Following Repeated Low-Level Red-Light Therapy for Myopia Control: Secondary Analysis of a Randomized Controlled Trial

PURPOSE

Repeated low-level red-light (RLRL) therapy has been confirmed as a novel intervention for myopia control in children. This study aims to investigate longitudinal changes in choroidal structure in myopic children following 12-month RLRL treatment.

MATERIALS AND METHODS

The current study is a secondary analysis from a multicenter, randomized controlled trial (NCT04073238). Choroidal parameters were derived from baseline and follow-up swept-source optical coherence tomography scans taken at 1, 3, 6, and 12 months. These parameters included the luminal area (LA), stromal area (SA), total choroidal area (TCA; a combination of LA and SA), and choroidal vascularity index (CVI; ratio of LA to TCA), which were automatically measured by a validated custom choroidal structure assessment tool.

RESULTS

A total of 143 children (88.3% of all participants) with sufficient image quality were included in the analysis (n=67 in the RLRL and n=76 in the control groups). At the 12-month visit, all choroidal parameters increased in the RLRL group, with changes from baseline of 11.70×10 3  μm 2 (95% CI: 4.14-19.26×10 3  μm 2 ), 3.92×10 3  μm 2 (95% CI: 0.56-7.27×10 3  μm 2 ), 15.61×10 3  μm 2 (95% CI: 5.02-26.20×10 3  μm 2 ), and 0.21% (95% CI: -0.09% to 0.51%) for LA, SA, TCA, and CVI, respectively, whereas these parameters reduced in the control group.

CONCLUSIONS

Following RLRL therapy, the choroidal thickening was found to be accompanied by increases in both the vessel LA and SA, with the increase in LA being greater than that of SA. In the control group, with myopia progression, both the LA and SA decreased over time.

Photobiomodulation therapy retarded axial length growth in children with myopia: evidence from a 12-month randomized controlled trial evidence

To determine whether photobiomodulation (PBM) therapy can retard ocular axial length (AL) in children with myopia. A randomized controlled clinical trial was conducted on two consecutive cohorts of 50 eligible children aged 8-12 years with ≤ - 0.75 Diopter (D) of spherical equivalent refraction (SER). Participants were randomly assigned to the intervention group (n = 25) and treated with PBM therapy or the control group (n = 25) and treated with single vision spectacles only. At the 12-month follow-up, the changes in AL and cycloplegic SER from baseline were both compared between the two groups. In addition, the subfoveal choroidal thickness (SFChT), anterior chamber depth (ACD), and central corneal refractive power (CCP) were analysed at the 3-, 6-, 9-, and 12-month follow-ups, respectively. Among the 50 children, 78% were included at the final follow-up, with a mean age of 9.7 ± 1.5 years and a mean SER of - 2.56 ± 1.70. The mean difference in AL growth between the two groups at 12 months was 0.50 mm (PBM vs. Control, - 0.02 mm ± 0.11 vs. 0.48 mm ± 0.16, P < 0.001), and the mean difference in cycloplegic SER at 12 months was + 1.25 D (PBM vs. Control, + 0.28 D ± 0.26 vs. - 0.97 D ± 0.25, P < 0.001). There were no significant differences in any of the other parameters (including SFChT, ACD, and CCP) between the two groups at any time point. PBM therapy is an effective intervention for slightly decreasing the AL to control myopia in children.Trial registration: Chinese Clinical Trial Registration Number: ChiCTR2100043619. Registered on 23/02/2021; prospectively registered. http://www.chictr.org.cn/showproj.aspx?proj=121302 .

Choroidal thickness, myopia, and myopia control interventions in children: a Meta-analysis and systemic review

AIM

To investigate changes of choroidal thickness (ChT) in children with myopia and the effect of current myopia control interventions on ChT.

METHODS

Major literature databases were searched for studies relevant to myopia in children. All studies used swept-source optical coherence tomography (SS-OCT) or enhanced depth imaging optical coherence tomography (EDI-OCT) to measure the ChT value. The weighted mean difference (WMD) and 95% confidence interval (CI) were pooled to evaluate ChT in myopia children.

RESULTS

A total of 11 eligible articles, including 1693 myopic and 1132 non-myopic eyes, were included in the first Meta-analysis. The sub-foveal choroidal thickness (SFCT; WMD=-40.06, 95%CI, -59.36 to -20.75, P<0.001) and ChT at other sectors were significantly thinner in myopic eyes compared with the non-myopic eyes. The Meta-analysis revealed that the ChT decreased horizontally from the temporal sector toward the nasal sector in the pediatric myopia population. Another 11 studies reporting the effect of myopia control interventions were included in the second Meta-analysis for the relationship between myopia control treatments and ChT. SFCT significantly increased after orthokeratology (OK) treatment and OK combined with 0.01% atropine (OKA) treatment (WMD=19.47, 95%CI, 15.96 to 22.98, P<0.001; WMD=21.81, 95%CI, 12.92 to 29.70, P<0.001, respectively). The forest plots showed that SFCT changed little in myopic children receiving 0.01% atropine (P=0.30). Furthermore, the Meta-analysis showed that OK treatment had a stronger effect on the value of SFCT in myopic children as compared with 0.01% atropine (WMD=9.86; 95%CI, -0.21 to 19.93, P=0.05). There is no difference between the treatment with OK and OKA treatment in ChT in myopic children (P=0.37).

CONCLUSION

The ChT in myopic eyes is thinner than that in non-myopic eyes in pediatric population. Myopia control interventions including OK and OKA lead to ChT thickening, but other treatments such as 0.01% atropine did not show an increase in ChT.