Short-Term Effects of Atropine 0.01% on the Structure and Vasculature of the Choroid and Retina in Myopic Chinese Children

The Short-term Effect of Atropine 0.1% on the Axial Length and Choroid of Children Treated for Myopia Progression Prevention, Measured by Optical Coherence Tomography Angiography

PURPOSE

To investigate the short-term effect of atropine to better understand its mechanism of action in myopia prevention. The current study investigates whether atropine's effect on the axial length arises from an increase in choroidal thickness using swept-source optical coherence tomography angiography (OCTA).

METHODS

Twenty-five myopic children (25 eyes) (9 boys and 16 girls; mean age: 11.8 years, range: 7 to 15 years) were enrolled following documented myopia progression and axial length increase in the preceding 6 months. Using swept-source OCTA, choroidal thickness and choroidal stromal volume (CSV) were measured at baseline and after 1 month of daily atropine 0.1% use. Axial length measurements were taken on the same days.

RESULTS

Following 1 month of daily atropine 0.1% instillation, choroidal thickness increased from 284.24 ± 65.05 to 308.04 ± 70.65 µm (Δ 22.41 ± 4.20 µm, P < .01), CSV increased from 11.88 ± 5.20 to 12.96 ± 5.86 mm3 (Δ 1.08 ± 1.02 mm3, P < .01), and axial length decreased from 25.37 ± 1.21 to 25.33 ± 1.21 mm (Δ 0.044 ± 0.016 mm, P < .05). The CSV and choroidal thickness increase show a negative correlation with the axial length decrease of -0.462 and -0.374, respectively, demonstrating a weak to moderate correlation.

CONCLUSIONS

One month of daily atropine 0.1% eye drop administration results in an acute decrease in axial length concurrent with an increase in choroidal thickness and CSV. A direct cause-and-effect relationship between these two parameters is plausible. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XXXXXX.].

Evaluating the effect of 0.125% atropine on foveal microvasculature using optical coherence tomography angiography

This study investigated alterations in the foveal microvasculature following the administration of 0.125% atropine in myopic children. In this prospective study, 63 eyes from 36 individuals aged 5-18 years with myopia were administered 0.125% atropine for myopia control. After administration, foveal microvascular parameters such as the area and perimeter of the foveal avascular zone (FAZ), the acircularity index (AI) of FAZ, and foveal vessel density were evaluated longitudinally. The effect of atropine on foveal microvasculature was analyzed using a linear mixed model. One month after atropine application, the area and perimeter of FAZ significantly decreased (p = 0.014 and 0.041). A significant decrease in vessel density within the 300-µm wide annulus around FAZ and an increase in the AI of the FAZ were observed in the initial 3-month period (p = 0.035 and p = 0.047, respectively). However, changes in the FAZ area, perimeter, AI and foveal vessel density throughout the follow-up were not significant. These findings suggest that 0.125% atropine may induce transient changes in FAZ size and foveal vessel density, but its overall safety in managing myopia is supported by the stability of foveal parameters over time.

Effectiveness of various atropine concentrations in myopia control for Asian children: a network meta-analysis

Objectives

To assess the effectiveness of various atropine concentrations in managing myopia among children in East, South, and Southeast Asia, and to determine the most effective concentration.

Methods

A systematic literature review was conducted using PubMed, Web of Science, Cochrane Library, and EMBASE. The search was limited to articles published up to 1 June 2024, and included studies in Chinese or English. Two researchers independently screened the literature, extracted relevant data, and assessed the data quality using the Revised Cochrane risk-of-bias 2 (RoB2) tool. A network meta-analysis was performed using Stata 14.2 software to compare the efficacy of different atropine concentrations in delaying myopia progression, measured by changes in refraction and axial length.

Results

The analysis included 39 studies with 7,712 participants, examining 10 atropine concentrations ranging from 0.005% to 1%. Forest plots indicated that five concentrations (0.01%, 0.02%, 0.025%, 0.05%, and 1%) were more effective than a placebo in controlling myopia progression. The cumulative ordination plot indicated that 0.05% atropine most effectively delayed refraction change, which the mean change per year was 0.62D, while 1% was superior in slowing axial length progression, which the mean change per year was -0.43 mm. Considering both measures, 1% atropine showed the highest efficacy which the mean changes per year were 0.56D in spherical equivalent refraction and -0.43 mm in axial length, followed by 0.05% and 0.125% atropine.

Conclusion

While 1% atropine demonstrated the highest efficacy in myopia control among East, South and Southeast Asian children, its use is not recommended due to increased adverse effects and a rapid rebound in myopia after cessation. Considering both efficacy and safety, 0.05% atropine is suggested as the optimal concentration for myopia management in this population.

The Macular Choroidal Thickness in Danish Children with Myopia After Two-Year Low-Dose Atropine and One-Year Wash-Out: A Placebo-Controlled, Randomized Clinical Trial

INTRODUCTION

Our aim in this work was to investigate the macular choroidal thickness (ChT) changes in 6-12-year-old Danish children with myopia during 2 years of low-dose atropine treatment and 1-year wash-out vs. placebo in an investigator-initiated, placebo-controlled, double-blind randomized clinical trial.

METHODS

Ninety-seven participants were randomized to either 0.01% for 2 years, 0.1% loading dose for 6 months followed by 0.01% for 18 months, or placebo, then a 1-year wash-out. The primary outcome was ChT in the sub-foveal and inner and outer superior, nasal, inferior, and temporal sectors. The secondary outcome was axial length (AL). Outcomes were measured at baseline and 6, 12, 24, and 36 months. One-way analysis of variance was used to detect baseline ChT differences between AL-stratified groups (< 24 mm, 24-25 mm, or > 25 mm). To determine the longitudinal changes in ChT and its effect on AL, all eyes were included in linear mixed modeling with individual eyes nested in the study ID as a random effect.

RESULTS

Longer eyes had significantly thinner ChT in all choroidal sectors (adj-P < 0.01) at baseline. There was no statistically significant change in any ChT sector after 3 years in the placebo group. Sub-foveal and nasal ChT in the 0.1% loading dose and 0.01% group were not significantly different from placebo after 2-year treatment. In the placebo group, a 1-mm increase in AL was significantly associated with a 47-µm thinner nasal ChT after 3 years (95% confidence interval (CI): - 55; - 38, adj-P < 0.001). A 10-µm thicker nasal choroid at baseline was associated with 0.13 mm (95% CI: 0.009; 0.017, adj-P < 0.001) less 3-year axial elongation.

CONCLUSIONS

The ChT in Danish children with myopia remained stable over the 3-year follow-up. A thinner choroid at myopia onset might predispose to increased axial elongation. Treatment with 0.01% atropine did not change the ChT. We speculate that low-dose atropine does not primarily reduce myopia progression via a choroidal mechanism.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT03911271.

Effects of atropine on choroidal thickness in myopic children: a meta-analysis

Background

Atropine is an effective medicine for myopia prevention and control. This meta-analysis was conducted to investigate the effects of atropine on choroidal thickness (ChT) in children with myopia.

Methods

Between its inception and 1 June 2023, Medline, Embase, and Web of Science were all searched, and only English literature was included. The choroidal thickness was the primary study outcome. Axial length, standardized equivalent refraction were examined as secondary outcomes. STATA 12.0 was used for data extraction and analysis.

Results

A total of 307 eyes were involved in this study to evaluate the effect of atropine on ChT, axial length (AL) and standardized equivalent refraction (SER) in myopic children. Choroidal thickening was significantly higher in the atropine group than in the control group at 1 month (WMD, 6.87 mm, 95% CI, 0.04 to 13.10, P = 0.049), whereas it was significantly higher in the atropine group than in the control group at months 6 (WMD, 10.37 mm, 95% CI, -3.21 to 23.95, P = 0.135), 12 (WMD, 15.10 mm, 95% CI, -5.08 to 35.27, P = 0.143) and at final follow-up (WMD, 11.52 mm, 95% CI, -3.26 to 26.31, P = 0.127), the differences were not statistically significant. At months 1 (WMD, -0.03 mm, 95% CI, -0.04 to -0.01, P = 0.003), 6 (WMD, -0.07 mm, 95% CI, -0.01 to -0.03, P = 0.000), 12 (WMD, -0.13mm, 95% CI, -0.15 to -0.11, P = 0.843), and at final follow-up (WMD, -0.08 mm, 95% CI, -0.16 to -0.01, P = 0.127), atropine treatment was able to delay the axial elongation. At 1-month follow-up, there was no significant difference in the effect of atropine on SER in myopic children compared with the control group (WMD, 0.01D, 95% CI, -0.07 to 26.31, P = 0.127), whereas it was able to control the progression of refractive status at final follow-up (WMD, 11.52 mm, 95% CI, -3.26 to 26.31, P = 0.127).

Conclusion

Limited evidence suggests that 0.01% atropine causes choroidal thickening in myopic children at 1 month of treatment. In the short term, choroidal thickness may be a predictor of the effectiveness of atropine in controlling myopia in children. 0.01% atropine is effective in controlling myopic progression in terms of SER and AL.

Systematic Review Registration

http://www.crd.york.ac.uk/prospero, identifier, CRD42022381195.

Comparison of Changes in Retinal Vascular Density and Thickness After Using Low-Level Red Light and 0.01% Atropine in Premyopic Children

Purpose

To compare changes in superficial retinal vascular density (SRVD), deep retinal vascular density (DRVD), and retinal thickness (RT) of the macular zone after repeated low-level red light (RLRL) and 0.01% atropine exposure in premyopic schoolchildren.

Methods

Prospective randomized trial. Sixty-nine schoolchildren with cycloplegic refraction >-0.75 D and ≤0.50 D were randomly assigned to RLRL and 0.01% atropine groups. SRVD, DRVD, and RT were measured using swept-source optical coherence tomography at baseline and six months. The macular zone was divided into three concentric rings (fovea, parafovea, and perifovea) using the Early Treatment Diabetic Retinopathy Study.

Results

After six months, the whole, parafoveal, and perifoveal SRVD significantly increased in the two groups (all P < 0.05). Multivariate regression analyses showed that none of these changes varied significantly between the two groups (all P > 0.05), whereas foveal SRVD remained stable in both groups (all P > 0.05). In the RLRL group, the whole and perifoveal DRVD increased significantly (all P < 0.05), whereas no statistical difference was observed in the foveal and parafoveal DRVD. DRVD remained stable in the 0.01% atropine group (all P > 0.05). No significant differences were observed in RT changes between the two groups (all P > 0.05). In comparison, there were no significant changes in SRVD, DRVD, or RT after six months in the placebo group in our previous study.

Conclusions

SRVD increased similarly in the RLRL and 0.01% atropine groups, whereas DRVD increased only in the former group. There were no significant RT changes in either group after six months of treatment in premyopic schoolchildren.

Translational Relevance

This research observed the effects of low-level red light and 0.01% atropine on retinal vasculature, offering valuable insights into myopia progression prevention.

Myopia Is an Ischemic Eye Condition: A Review from the Perspective of Choroidal Blood Flow

Myopia is a common refractive error that affects a large proportion of the population. Recent studies have revealed that alterations in choroidal thickness (ChT) and choroidal blood flow (ChBF) play important roles in the progression of myopia. Reduced ChBF could affect scleral cellular matrix remodeling, which leads to axial elongation and further myopia progression. As ChT and ChBF could be used as potential biomarkers for the progression of myopia, several recent myopia treatments have targeted alterations in ChT and ChBF. Our review provides a comprehensive overview of the recent literature review on the relationship between ChBF and myopia. We also highlight the importance of ChT and ChBF in the progression of myopia and the potential of ChT as an important biomarker for myopia progression. This summary has significant implications for the development of novel strategies for preventing and treating myopia.

Eye Diseases: When the Solution Comes from Plant Alkaloids

Plants are an incredible source of metabolites showing a wide range of biological activities. Among these, there are the alkaloids, which have been exploited for medical purposes since ancient times. Nowadays, many plant-derived alkaloids are the main components of drugs used as therapy for different human diseases. This review deals with providing an overview of the alkaloids used to treat eye diseases, describing the historical outline, the plants from which they are extracted, and the clinical and molecular data supporting their therapeutic activity. Among the different alkaloids that have found application in medicine so far, atropine and pilocarpine are the most characterized ones. Conversely, caffeine and berberine have been proposed for the treatment of different eye disorders, but further studies are still necessary to fully understand their clinical value. Lastly, the alkaloid used for managing hypertension, reserpine, has been recently identified as a potential drug for ameliorating retinal disorders. Other important aspects discussed in this review are different solutions for alkaloid production. Given that the industrial production of many of the plant-derived alkaloids still relies on extraction from plants, and the chemical synthesis can be highly expensive and poorly efficient, alternative methods need to be found. Biotechnologies offer a multitude of possibilities to overcome these issues, spanning from genetic engineering to synthetic biology for microorganisms and bioreactors for plant cell cultures. However, further efforts are needed to completely satisfy the pharmaceutical demand.

Atropine: Updates on myopia pharmacotherapy

The prevalence of myopia has rapidly increased over the last 30 years, with the World Health Organization estimating a worldwide incidence of 23%, projected to increase to 50% by 2050. The myopia epidemic has prompted a reincarnation in efforts to overcome this challenge. The exploration of atropine use in myopia was a result due to a lack of treatment in effect. This study aimed at reviewing the role of atropine in the management of myopia worldwide based on currently available findings. A literature search was conducted using PubMed/MEDLINE and Google Scholar for studies published up to April 2022 inclusive. Articles with high or medium clinical relevance were selected for this review. Multiple studies have demonstrated the relevance and efficacy rates of different concentrations of atropine, despite still insufficiently explained the exact site and mechanism of action of atropine in slowing myopia progression. Currently available findings highlight that topical atropine opened a new page in pharmacotherapy of myopia and have shown a high therapeutic effect on myopia progression in Asian and European child population, irrespective of ethnicity. There is potential for myopia control with fewer side effects using lower concentrations but still exists a room for improvement, underscoring the requirement of modified atropine topical preparations with increased bioavailability, potentially with nanoparticle formulations, to enable the effective management of myopia.

Defocus incorporated multiple segments (DIMS) spectacle lenses increase the choroidal thickness: a two-year randomized clinical trial

BACKGROUND

Myopia control interventions, such as defocus incorporated multiple segments (DIMS) spectacle lenses, have been adopted in school-aged children to reduce the prevalence of myopia and its complications. This study aimed to investigate the effect of DIMS spectacle lenses on subfoveal choroidal thickness (SfChT) over a period of two years, as the choroidal response to myopic control is a crucial factor in exploring its potential effect on predicting myopia progression.

METHODS

This study involved a secondary analysis of our previous randomized clinical trial. Myopic school-aged children aged 8-13 years were recruited in a two-year study investigating the effect of DIMS spectacle lenses on myopia progression. The treated group received DIMS spectacle lenses (n = 78), while the control group was treated with a pair of single vision (SV) spectacle lenses (n = 80). SfChT was monitored at 1 week, 1, 3, 6, 12, 18 and 24 months post lens wear using spectral-domain optical coherence tomography and a custom made auto-segmentation algorithm utilizing convolutional neural networks.

RESULTS

SfChT increased significantly after one week of DIMS spectacle lens wear compared to those wearing SV spectacle lenses (adjusted mean change relative to baseline ± SEM at one week; DIMS vs. SV, 6.75 ± 1.52 µm vs. - 3.17 ± 1.48 µm; P < 0.0001, general linear model). The thickness of choroid increased to 13.64 ± 2.62 µm after 12 months of DIMS lens wear while the choroid thinned in SV group (- 9.46 ± 2.55 µm). Choroidal changes demonstrated a significant negative association with axial elongation over two years in both the DIMS and SV groups. Choroidal change at three months significantly predicted the changes in AL at 12 months after controlling the effect of age and gender.

CONCLUSIONS

Our study demonstrated a significant choroidal thickening in response to myopic defocus incorporated in a spectacle lens after one week of lens wear, sustained over the two-year study period. The results suggested that choroidal changes at three months may help predict changes in axial length after one year. Trial registration ClinicalTrials.gov. Myopia control with the multi-segment lens. NCT02206217. Registered 29 July 2014, https://clinicaltrials.gov/ct2/show/study/NCT02206217.

Efficacy and safety of atropine at different concentrations in prevention of myopia progression in Asian children: a systematic review and Meta-analysis of randomized clinical trials

AIM

To assess the efficacy versus the adverse effects of various concentrations of atropine in the prevention of myopia in Asian children.

METHODS

Databases (PubMed, EMBASE, the Cochrane Library and Web of science) were comprehensively searched from inception to April 2022. Types of studies included were randomized clinical trials (RCTs). The published languages were limited to English. Two researchers assessed the quality of included studies independently using Cochrane risk of bias tool based on the Cochrane Handbook for Systematic Reviews of Interventions. Funnel plots and Egger's test were used for detection of publication bias. Meta-analyses were conducted using STATA (version 15.0; StataCorp).

RESULTS

A total of 15 RCTs involving 2268 patients were included in the study. In the atropine group, spherical equivalent progressed at a significantly lower rate [weighted mean difference (WMD)=0.39, 95% confidence interval (CI): 0.23, 0.54] than in the control group. A WMD of 0.15 mm was associated with less axial elongation (95%CI -0.19, -0.10). Different doses showed statistically significant differences (P<0.05) and an improved effect could result from a higher concentration. Changes in photopic pupil size and mesopic pupil size in atropine group is 0.70 mm (95%CI: 0.33, 1.06) and 0.38 mm (95%CI: 0.22, 0.54) more than the control group. In the present Meta-analysis, no changes in accommodative amplitude (AA) were associated with atropine administration. Atropine administration increased the risk of adverse effects by 1.37 times.

CONCLUSION

Concentrations of less than 1% atropine are able to effectively retard diopter and axis growth of myopia in Asian children in a dose-dependent manner. Meanwhile, it caused pupil enlargement, but induced no change in the AA within this range. Further study is required to determine the dosage needed to achieve maximum efficacy and minimal side effects.

Changes in choroidal thickness in myopic children with 0.01% atropine: Evidence from a 12-month follow-up

PURPOSE

To investigate the changes of low-dose atropine (0.01%) on the choroidal thickness (ChT) of young children with low myopia.

METHODS

A total of 25 eyes of 25 low myopic children were included. All subjects were prescribed 0.01% atropine eye drops to be applied once per night before bedtime in involving eyes. The ChT and ocular biometry parameters were measured before and after 1 month, 3 months, 6 months and 12 months. The children were followed up for 12 months.

RESULTS

At 3 months, the ChT under the fovea significantly increased (309.96±70.82 μm) in comparison with the baseline (297.92±66.31 μm, P<0.0001) and was continuous thickening till 12 months after treatments with 0.01% atropine. Similarly, the changes of ChT under the fovea significantly increased from baseline to 3 months in comparison with the baseline to 1 month after treatments (P<0.0001). There was a significant relationship between changes in subfoveal ChT and central cornea thickness (CCT, beta=-1.76, 95% confidence intervals: -3.49 to -0.04, P = 0.045).

CONCLUSIONS

Using low dose atropine eye drops significantly increased subfoveal ChT after 3 months in eyes of myopic children. In addition, the changes in subfoveal ChT may be associated with the changes of CCT.

Longitudinal Changes and Predictive Value of Choroidal Thickness for Myopia Control after Repeated Low-Level Red-Light Therapy

PURPOSE

To evaluate longitudinal changes in macular choroidal thickness (mCT) in myopic children treated for 1 year with repeated low-level red-light (RLRL) therapy and their predictive value for treatment efficacy on myopia control.

DESIGN

A secondary analysis of data from a multicenter, randomized controlled trial (RCT; NCT04073238).

PARTICIPANTS

Myopic children aged 8-13 years who participated in the RCT at 2 of 5 sites where mCT measurements were available.

METHODS

Repeated low-level red-light therapy was delivered using a home-use desktop light device that emitted red-light at 650 nm. Choroidal thickness was measured by SS-OCT at baseline and 1-, 3-, 6-, and 12-month follow-ups. Visual acuity, axial length (AL), cycloplegic spherical equivalent refraction (SER), and treatment compliance were measured.

MAIN OUTCOME MEASURES

Changes in mCT at 1, 3, 6, and 12 months relative to baseline, and their associations with myopia control.

RESULTS

A total of 120 children were included in the analysis (RLRL group: n = 60; single-vision spectacle [SVS] group: n = 60). Baseline characteristics were well balanced between the 2 groups. In the RLRL group, changes in mCT from baseline remained positive over 1 year, with a maximal increase of 14.755 μm at 1 month and gradually decreasing from 5.286 μm at 3 months to 1.543 μm at 6 months, finally reaching 9.089 μm at 12 months. In the SVS group, mCT thinning was observed, with changes from baseline of -1.111, -8.212, -10.190, and -10.407 μm at 1, 3, 6, and 12 months, respectively. Satisfactory myopia control was defined as annual progression rates of less than 0, 0.05, or 0.10 mm for AL and less than 0, 0.25, or 0.50 diopters for SER. Models that included mCT changes at 3 months alone had acceptable predictive discrimination of satisfactory myopia control over 12 months, with areas under the curve of 0.710-0.786. The predictive performance of the models did not significantly improve after adding age, gender, and baseline AL or SER.

CONCLUSIONS

This analysis from a multicenter RCT found RLRL induced sustained choroidal thickening over the full course of treatment. Macular choroidal thickness changes at 3 months alone can predict 12-month myopia control efficacy with reasonable accuracy.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

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.