Significant ocular residual astigmatism reduces the effect of orthokeratology lenses in controlling myopia

Abstract

To investigate the influence of ocular residual astigmatism (ORA) on the therapeutic outcomes of orthokeratology lenses in pediatric myopia management. In this retrospective cohort study, 60 myopic children aged 7–12 years were classified into high-ORA (≥ 1.00 D; n = 30) and low-ORA (< 1.00 D; n = 30) groups on the basis of their baseline ORA, defined as the vector difference between refractive astigmatism and anterior corneal astigmatism. Longitudinal follow-up assessments were conducted at 1 day, 7 days, 1, 3, 6, and 12 months post-lens fitting. Axial elongation (ΔAL) was calculated as the difference between sequential measurements and baseline values. Differences in axial elongation (ΔAL) during the follow-up period were statistically analyzed using repeated measures analysis of covariance (RM-ANCOVA). Multivariable linear regression was performed to identify determinants of 12-month ΔAL. The mean age was 8.8 ± 1.3 years, and the average annual axial growth was 0.22 ± 0.17 mm. Repeated-measures ANCOVA showed that time, group, and the time × group interaction significantly affected axial elongation (ΔAL, all P < 0.01), whereas baseline ACA did not (P = 0.671). The high-ORA cohort presented significantly greater mean axial elongation than the low-ORA group at all post baseline intervals except 1 month (3 months: P = 0.036; 6 months: P = 0.015; 12 months: P = 0.001). Regression analysis showed that the baseline ORA magnitude (β = 0.219, P < 0.001) and spherical equivalent refraction (β = 0.043, P = 0.038) were positive predictors of the annual ΔAL, whereas the patient’s baseline age was a negative predictor (β = -0.056, P < 0.001). High ORA (≥ 1.00 D) constitutes an independent risk factor for reduced orthokeratology efficacy in reducing axial elongation. This result emphasizes the importance of incorporating ORA assessment into the pretreatment assessment of orthokeratology lenses fitting. Children with high ORA may benefit from alternative interventions such as peripheral defocus soft contact lenses to optimize myopia management outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1038/s41598-026-38248-6.

Introduction

Myopia is one of the most common refractive errors. The prevalence of myopia is increasing worldwide, especially among children in East and Southeast Asia, where myopia has reached epidemic levels¹. The global prevalence of pediatric myopia has reached alarming levels, with projections suggesting that nearly 50% of the world’s population may be myopic by 2050². Myopia not only affects visual acuity and daily life but also increases the risk of serious ocular complications such as glaucoma, retinal detachment, and macular degeneration in the long term³. These potential complications can lead to significant visual impairment and even blindness, highlighting the urgent need for effective myopia control strategies.

Several approaches have been developed to manage myopia progression, including pharmacological treatments (such as low concentrations of atropine), optical interventions (such as multifocal glasses and peripheral defocus contact lenses) and behavioral modifications (such as increased outdoor time). Among these approaches, orthokeratology lenses have gained wide popularity due to their ability to temporarily reshape the corneal epithelium — they not only provide clear daytime vision without glasses, but also exhibit certain effectiveness in slowing down myopia progression^4–7.

Refractive astigmatism (RA), anterior corneal astigmatism (ACA), and ocular residual astigmatism (ORA) represent distinct categories of astigmatism with unique anatomical foundations⁸. The ORA is composed of the posterior corneal surface, crystalline lens, vitreous (to a lesser extent), retina, and perceptual physiology^9–11. The RA is fundamentally determined by the combined effect of the ACA and ORA. Clinically significant RA (≥ 1.0 D) can compromise contrast sensitivity, reduce visual acuity, disrupt normal visual development, and induce diverse ocular symptoms, such as blurred vision or asthenopia¹². Thankfully, the primary function of ORA is to compensate for ACA, thereby resulting in a lower RA⁸. Orthokeratology lenses remodel the corneal epithelium, disrupting the relationship between the ORA and ACA. Clinically significant ORA may impact the therapeutic outcomes of orthokeratology lenses. Although numerous studies have identified several factors influencing orthokeratology efficacy, such as baseline myopia and patient age^7,13, the influence of ORA on the clinical outcomes of orthokeratology has not been systematically investigated. A study found that ORA (negative value) was negatively correlated with axial length (AL) in newly diagnosed myopic children¹⁴. Does this same relationship exist after wearing orthokeratology lenses?

This study aimed to investigate the impact of ORA magnitude on the clinical outcomes of orthokeratology lenses in pediatric myopia management. Using a rigorous longitudinal design with standardized measurement protocols, the relationship between the baseline ORA and axial elongation progression was quantified. Additionally, potential interactions between ORA and established predictors of orthokeratology outcomes, including age and baseline refractive error, were explored. These findings may offer valuable insights for optimizing patient selection and formulating personalized myopia management strategies, especially for children with high ORA.

Materials and methods

Subjects

This was a retrospective cohort study. The clinical records of 60 children (30 in each group) were collected at a 1:1 ratio. Only right eye data were used for analysis¹⁵. The patients were divided into high ORA (ORA ≥ 1.0 D) and low ORA groups (ORA < 1.0 D) according to their baseline ORA with reference to clinically significant astigmatism criteria (≥ 1.0 D)¹². The subjects attended outpatient ophthalmology clinics from January 2023 to December 2024 and were fitted with orthokeratology lenses for one year. The inclusion criteria for the subjects were as follows: (1) myopic spherical refractive error between − 5.00 D and − 0.75 D; (2) regular refractive astigmatism between − 0.75 D and − 0.00 D; (3) flat keratometry values (FK) between 41.0 D and 45.5 D; (4) intraocular pressure < 21 mmHg; (5) discontinued wearing orthokeratology lenses for < 1 month during the year; (6) corneal height difference at 8-mm < 30; and (7) five follow-up examinations (1 day, 1, 3, 6 and 12 months after wearing the CRT spherical lenses) were complete and had a topography map with an intact plus power ring and lens decentration < 1.0 mm. (8) The uncorrected visual acuity (UCVA) was 20/25 or better, with the refractive error measured between + 0.75 and + 1.50 diopters (D) at the 12-month follow-up visit.

The exclusion criteria were as follows: (1) history of atropine treatment; (2) any current ocular or systemic disease; (3) wearing other types of orthokeratology lenses or changing the brand of the lens; (4) any contraindications to wearing contact lenses; and (5) lens decentration > 1 mm during ortho-k treatment.

The study was approved by the Lianyungang Maternal and Child Health Hospital Review Board (XM2023048) and was conducted in accordance with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Written informed consent was obtained from at least one parent of all participating children after explanation of the nature of the study.

Contact lens fitting

This study used spherical orthokeratology lenses (Paragon CRT lens, USA). The Dk of the lens was 100 × 10^{− 11} (cm2/s) (mL O2)/(mL · mm Hg). CRT lenses consist of three concentric regions arranged from center to periphery: an optical zone at the core, surrounded by a reverse zone, and finally a landing zone at the outer edge. The compression factor of the CRT lenses was + 0.50 D. The diameter of the back optical zone was 6.0 mm in this study¹⁶.

On the basis of the fitting guidelines provided by the manufacturer, the same doctor employed identical fitting methods to fit the lenses. The lenses were ordered with a goal of over-refraction ranging from + 0.50 D to + 1.00 D. The participants were asked to wear the lenses for a minimum of 8 consecutive hours each night. During the follow-up period, if notable lens decentration (more than 1.0 mm) is observed or uncorrected visual acuity drops below 20/25, a new lens is ordered. This process continues until the lens is well centered and the visual acuity recovers to 20/25 or better. Otherwise, the lenses should be replaced regularly every 12 to 18 months, which was in accordance with the recommended service life of ortho-K lenses to ensure optimal myopia control efficacy and ocular safety. All the participants and their guardians received education on how to wear and take care of the lenses¹⁷.

Clinical data collection and calculations

Prior to wearing orthokeratology lenses, all the subjects underwent a standardized examination, which included a slit lamp examination, corneal topography, measurement of AL, specular microscopy, and subjective refraction under noncycloplegia. After starting to wear orthokeratology lenses, the subjects were followed up in accordance with a standardized visit schedule. The follow - up visits were scheduled at 1 day, 1 week, 1 month, 3 months, 6 months, and 12 months. At each visit, data regarding general ocular health, lens fitting, visual acuity, and AL were collected. AL was measured five times using an Intraocular Lens Master (IOL - Master 500, Zeiss, Germany)¹⁸.

The axial elongation (ΔAL) refers to the difference between sequential measurements (1, 3, 6, and 12 months post-lens fitting) and baseline values. The Spherical equivalent refraction (SER) was calculated as spherical power + half-cylinder power. RA was obtained by standard subjective optometry. ACA was measured with an automated refractor/keratometer (ARK-1, NIDEK, Japan). Three consistent measurements were recorded, with their averages undergoing subsequent analysis. ORA was calculated as the vectorial difference between the RA and ACA. Please refer to our previous article for the specific calculation process of ORA¹⁹. ORA showed positive values, and SER showed negative values.

Statistics

Sample size

A study demonstrated that over a 2-year observation period, children wearing orthokeratology lenses exhibited distinct axial elongation patterns: the lower level of axial elongation group (40% of the subjects) showed ≤ 0.30 mm of growth over two years (equivalent to ≤ 0.15 mm annually), whereas the higher rate of axial elongation group (25% of the subjects) experienced > 0.59 mm growth during the same period (approximately > 0.30 mm per year)⁵. Additionally, Liu et al.²⁰ reported a mean annual axial length increase of 0.22 ± 0.17 mm in children wearing OK lenses.

Therefore, a sample size calculated with an absolute difference in annual axial elongation of 0.15 mm, an alpha of 0.05, a power of 90%, a test-to-control ratio of 1:1, and a standard deviation of 0.17 mm would require a total of at least 54 patients to be studied.

Statistical analyses

Only right eye data were used for analysis. Statistical analyses were performed using IBM SPSS Statistics for Windows, Version 25.0 (IBM Corp., Armonk, NY, USA). The normality of all data samples was checked by means of the Kolmogorov–Smirnov test. The magnitudes of ORA, ACA and refractive astigmatism were non-normally distributed. They were expressed as the median value and interquartile range (IQR). The remaining data were normally distributed and were expressed as the mean ± standard deviation (SD). Difference tests (independent sample t tests or non-parametric tests, depending on whether normal conditions can be assumed) were used to compare the baseline characteristics between the two groups of subjects. Repeated measures analysis of covariance (RM-ANCOVA) was employed to assess group differences, time effects, and their interactions. The Bonferroni correction test was used for multiple comparisons. Stepwise multiple linear regression analysis was employed to assess the factors influencing axial elongation at 12 months, such as initial age, sex, initial SER, initial ACA, initial ORA, initial AL, and initial FK. P < 0.05 was considered to be statistically significant.

Results

Baseline data

This study enrolled 60 myopic children aged 7–12 years (mean age: 8.8 ± 1.3 years), who were equally divided into high and low ORA groups (30 children each; 20 girls and 10 boys per group). At baseline, the SER ranged from − 4.875 D to −0.875 D, the FK from 41.0 D to 45.5 D, the AL from 22.90 mm to 25.93 mm, the flat eccentricity (e) from 0.43 to 0.91 and the horizontal visible iris diameter (HVID) from 10.80 mm to 13.10 mm. The ACA ranged from 0.25 to 2.25 D. Comparisons of baseline characteristics between the two groups are presented in Table 1.

Table 1.

Comparison of two sets of baseline data.

Group	Age (years)	AL (mm)	FK (D)	SER (D)	Flat eccentricity	ACA (D)	HVID (mm)
High ORA	8.9 ± 1.3	24.06 ± 0.60	43.15 ± 1.15	−2.19 ± 0.87	0.64 ± 0.07	1.25(0.56)	11.94 ± 0.44
Low ORA	8.8 ± 1.2	24.28 ± 0.67	42.95 ± 1.20	−2.28 ± 0.98	0.67 ± 0.11	0.75(0.50)	11.86 ± 0.47
T/Z	−0.203	1.331	−0.660	−0.365	−1.185	−0.504	−0.677
P	0.840	0.188	0.52	0.717	0.241	< 0.001	0.501

ORA= ocular residual astigmatism; AL= axial length; FK = flat keratometry values.

SER = spherical equivalent refraction; HVID = horizontal visible iris diameter.

D = diopter; ACA = anterior corneal astigmatism.

Comparison of axial elongation (ΔAL) between the two groups at different time points

The mean annual axial growth of all the children was 0.22 ± 0. 17 mm. The ΔAL of the two groups of patients followed a normal distribution, and the variance was uniform. Repeated measures analysis of covariance (RM-ANCOVA) was used to compare the ΔAL at 1, 3, 6, and 12 months between the high and low ORA groups. The model included time (1, 3, 6, and 12 months) as the within-subjects factor, ORA grouping (0 = low ORA group, < 1.00 D; 1 = high ORA group, ≥ 1.00 D) as the between-subjects factor, and baseline ACA as the covariate (to adjust for baseline imbalance). Model assumption validation showed that Box’s test for equality of covariance matrices was non-significant (P = 0.472), indicating homogeneous covariance across groups; Mauchly’s test of sphericity was significant (P < 0.05), so the Greenhouse‒Geisser correction was applied for subsequent analyses.

The results showed that time, inter-group and time × group interactions had significant effects on ΔAL. The covariate “baseline corneal astigmatism” had no significant effect on ΔAL (Table 2).

Table 2.

Intra/Inter-Subject effect test results (RM-ANCOVA).

Effect term	F	P	η²
group interaction	9.107	0.004	0.138
time interaction	12.070	< 0.001	0.175
ACA interaction	0.183	0.671	0.003
time × ACA interaction	0.059	0.904	0.001
time × group interaction	10.377	< 0.001	0.154

Note: Since the spherical assumption is not met, RM-ANOVA uses Greenhouse - Geisser correction.

After adjusting for corneal astigmatism, the estimated marginal means (Table 3) indicated that the corrected ΔAL increased gradually in the low ORA group, whereas the high ORA group exhibited a steeper growth trajectory, with the between-group difference expanding over time. Univariate ANOVA stratified analysis was used, combined with Bonferroni multiple comparison correction. The results showed that the mean corrected ΔAL was greater in the high ORA group than in the low ORA group at all other time points except one month (Table 3).

Table 3.

Differences in the corrected ΔAL (mm) at different time points.

corrected Δ AL	High ORA group			Low ORA group			F	P
	Mean	SE	95% CI	Mean	SE	95% CI
one month	0.020	0.010	−0.001 ~ 0.040	−0.006	0.010	−0.027 ~ 0.014	2.580	0.114
three month	0.075	0.017	0.041 ~ 0.109	0.017	0.017	−0.017 ~ 0.051	4.620	0.036
six month	0.143	0.023	0.097 ~ 0.189	0.052	0.023	0.006 ~ 0.097	6.262	0.015
twelve month	0.314	0.031	0.251 ~ 0.377	0.132	0.031	0.069 ~ 0.195	13.282	0.001

SE = standard error; CI = confidence interval; ORA = ocular residual astigmatism.

For the evaluation of the covariates included in the model, the following value was assigned: ACA = 1.0875.

Figure 1 visually confirmed that the slope of the corrected ΔAL growth was steeper in the high ORA group than in the low ORA group, and the 95% confidence intervals of the two groups did not overlap in the later follow-up period (Months 6–12).

Fig. 1.

The changing trends of the corrected ΔAL at different time points over one year for the two groups.

For the evaluation of the covariates included in the model, the following value was assigned: ACA = 1.0875. The error bars represent the 95% confidence intervals.

In the low ORA group, the ΔAL was ≤ 0.1 mm/year in 33.3% (10/30) and ΔAL > 0.2 mm/year in 36.7% (11/30) of patients. Axial length shortening occurred in 10.0% (3/30) of this group. Conversely, the high ORA group demonstrated less stabilization (ΔAL ≤ 0.1 mm/year: 3.3%, 1/30) and a higher proportion of rapid progression (ΔAL > 0.2 mm/year: 73.3%, 22/30). No axial length shortening was observed in the high ORA group. Figure 2 shows the specific details.

Fig. 2.

Annual AL elongation data for the two groups.

Factors related to myopia retardation with orthokeratology lenses

To assess the influence of the baseline SER, AL, FK, ACA, and ORA on the annual change in axial length (ΔAL), multiple linear regression analysis was performed. Age and sex were included as covariates. Using these seven baseline variables as predictors, stepwise regression yielded three significant models (F values: 8.565, 11.498, and 9.646; R²values: 0.129, 0.287, and 0.341, respectively). The optimal predictive model parameters are detailed in Table 4. The analysis revealed that the annual ΔAL was positively associated with the baseline SER and baseline ORA but negatively associated with the baseline age. No significant associations were found between the annual ΔAL and sex, baseline FK, or baseline AL.

Table 4.

Prediction model parameters for ΔAL.

Variables	B	SE for B	95.0% CI for B		t	P	R 2
			Lower	Upper
Constant	0.633	0.141	0.350	0.916	4.485	< 0.001	0.341
Age	−0.056	0.015	−0.086	−0.027	−3.808	< 0.001
ORA	0.219	0.055	0.109	0.329	3.998	< 0.001
SER	0.043	0.020	0.002	0.083	2.127	0.038

CI = confidence interval; SE = standard error; ORA= ocular residual astigmatism.

SER = spherical equivalent refraction; ΔAL = axial elongation.

Discussion

To the best of our knowledge, this is the first study investigating the impact of ORA on the axial elongation control efficacy of orthokeratology lenses. The findings demonstrated that a high ORA (≥ 1.00 D) significantly reduces the therapeutic effectiveness of spherical CRT in slowing axial elongation in myopic children. Furthermore, multiple linear regression analysis also showed a positive correlation between the annual ΔAL and baseline ORA. This attenuated effect may be attributed to the exposure of high ORA following corneal remodelling completion. Orthokeratology remodels the corneal epithelium through central epithelial thinning and peripheral thickening. That is, only the anterior cornea was remodelled, and there was no effect on the intraocular structure. Extensive research has shown that orthokeratology induces measurable alterations in anterior corneal astigmatic parameters^21–23. Mountford and Pesudovs²¹ reported 87% ACA improvement rates with reverse-geometry orthokeratology lens designs. Subsequent investigations by Chan²² quantified a maximal ACA reduction in the ACA of −2.50 D after 21 days of orthokeratology lens wear. Chen’s research team²³ reported a 79% decrease in the ACA in moderate-to-high astigmatism patients after one month of orthokeratology therapy. As a result, the ACA decreased significantly after orthokeratology, while the ORA became predominant. Notably, ORA predominantly manifests as against-the-rule astigmatism, which contributes to suboptimal optical quality that potentially compromises the therapeutic efficacy of myopia control. Furthermore, there may be an underlying optical mechanism related to the quality and amount of peripheral defocus. OK lenses primarily reshape the central cornea to induce myopic defocus in the peripheral retina, which is believed to inhibit axial growth²⁴. However, in eyes with significant ORA, the inherent toricity of the posterior corneal or lenticular surfaces may disrupt the symmetry and uniformity of the peripheral refractive profile generated by OK. This could lead to inconsistent or asymmetric myopic defocus patterns, reducing the overall inhibitory signal for axial elongation. Furthermore, Queirós et al.²⁵ found that a higher level of myopic defocus induction appeared to be positively associated with a reduction in axial length over 12 months. A higher ORA exposed after orthokeratology may compromise the amount and stability of peripheral myopic defocus. Thus, the diminished efficacy in high ORA may stem from suboptimal induction of consistent peripheral myopic defocus, underscoring the need for customized OK designs in these cases.

A previous study found a negative correlation between the ORA (negative value) and AL in children with newly diagnosed myopia¹⁴. In contrast, the present study demonstrated a positive correlation between the annual ΔAL and baseline ORA (positive value) in children wearing spherical CRT by multiple linear regression analysis. While the results may appear contradictory at first glance, standardizing the notation of ORA leads to a convergent conclusion. This consistency underscores that a greater magnitude of ORA may be regarded as an important predictor and contributing factor for myopia onset and rapid progression.

Previous studies have shown that epithelial remodelling caused by wearing orthokeratology lenses takes approximately one month^26–28. The current study found that the difference in effectiveness between the two groups in controlling axial elongation began to emerge after one month of wearing orthokeratology lenses. After orthokeratology was completed, the high ORA was exposed, and there was a difference in axial elongation between the two groups, which also verified the therapeutic efficacy of high ORA potentially impairing myopia control.

Notably, axial length regression was observed in 10.0% of participants in the low ORA group, whereas no such cases were detected in the high ORA group. The exact biological mechanism remains unclear. We hypothesize that in certain individuals with low ORA, the myopic defocus signals induced by orthokeratology (ortho-k) may be abnormally effective, or that the eye’s emmetropization feedback mechanism is highly sensitive, leading to a transient, active reduction in axial length. This phenomenon may be influenced by individual variations in choroidal thickness, scleral remodelling responsiveness, or the magnitude and profile of achieved peripheral myopic defocus. We believe that this observation warrants further investigation in specifically designed longitudinal studies to explore the determinants of this distinct treatment response.

These findings have significant clinical implications for myopia management in pediatric patients. For children with high ORA, spherical CRT may not be the optimal first-line treatment due to its reduced efficacy in controlling axial elongation. Instead, defocus soft contact lenses could be prioritized, as they offer several advantages. Firstly, defocus soft contact lenses do not induce corneal epithelial reshaping, thereby eliminating the risk of ORA exposure. Secondly, although defocus soft contact lenses do not directly alter the entity of astigmatism, a stable “post-lens tear film” is formed by the tears interposed between the lens and the cornea during daily wear. This post-lens tear film helps correct low refractive astigmatism, and for higher refractive astigmatism, the toric defocus soft lens is available as an option. In stark contrast, orthokeratology (ortho-K) lenses are prescribed for overnight wear and are removed upon awakening, which means the corrective benefit conferred by the post-lens tear film is absent during the diurnal period. Finally, studies have demonstrated that defocus soft contact lenses are more effective than single-vision lenses in slowing axial elongation and, in some cases, even more effective than orthokeratology lenses^29,30. Specifically, a recent meta-analysis showed that peripheral defocus soft contact lenses demonstrated superior effectiveness compared to single vision lenses in controlling myopia progression among children and adolescents²⁹. Li et al.³⁰ even suggested that for children with SER < −2.50 D, defocus incorporated soft contact lenses showed significantly better myopia control outcomes compared to 6.2 mm back optic zone diameters orthokeratology lenses. Whether toric CRT is suitable for children with high ORA still needs further study.

This study identified baseline age as a negative predictor of annual ΔAL and baseline SER as a positive predictor. The annual ΔAL was not significantly correlated with sex or baseline FK. These findings are consistent with those of Zhang et al³¹., who reported that in orthokeratology lens wearers, annual AL elongation was negatively correlated with initial age, positively correlated with baseline SER, and not significantly associated with sex or K-value. Several previous studies have also supported that baseline age is a significant negative determinant of axial prolongation^20,32,33. Specifically, a 2-year prospective randomized controlled study of 78 myopic participants (37 in the ortho-k group and 41 in the control group) showed that baseline age was a significant negative determinant of axial elongation (β = −0.39, P< 0.001)³². Huang et al.³³ also found that axial elongation was less one year after wearing orthokeratology lenses when the patient’s age at the initial stage was higher. A recent retrospective study of 1192 orthokeratology lenses users also found that axial elongation was negatively associated with baseline age and positively associated with baseline SER²⁰. A retrospective study of 116 children using orthokeratology lenses for two years also reported that AL changes were associated with a younger baseline age and greater baseline SER³⁴. However, Chen et al.¹³ proposed divergent findings, highlighting that younger age, lower baseline myopia, and a steeper FK were linked to superior myopia control efficacy during orthokeratology intervention. Furthermore, Lin et al.³⁵ reported a negative correlation between axial elongation and the baseline AL in the Ortho-K group. The characteristics of the study population, unaccounted environmental modifiers, and technical protocol differences likely drove the observed inconsistencies. Standardized reporting of baseline characteristics and multicenter longitudinal designs with harmonized confounder measurement may reconcile these disparities in future research.

Several limitations of this study warrant consideration. First, despite our efforts to match baseline characteristics between groups, the retrospective design may introduce selection bias and limit the generalizability of the findings. Second, the 12-month follow-up period may be insufficient to fully capture long-term differences in axial elongation progression. Third, the sample size, although adequate for statistical analysis, may not fully capture the heterogeneity of pediatric myopia populations. Fourth, only the effects of spherical CRT lenses were analyzed in the present study, and whether toric CRT lenses or other brands exhibit the same phenomenon requires further investigation. Finally, we did not assess other potential confounding factors, such as outdoor activity time or near work duration, which may influence myopia progression. Future prospective studies with larger cohorts, longer follow-up periods, more brands and comprehensive assessments of environmental factors are needed to validate our findings.

In conclusion, this study shows that high ORA significantly reduces the efficacy of spherical CRT in controlling axial elongation in pediatric myopia patients. The findings emphasize the importance of preoperative ORA assessment and suggest that alternative myopia control strategies, particularly defocus soft contact lenses, may be more appropriate for children with high ORA. These insights contribute to the growing body of evidence supporting personalized approaches to myopia management on the basis of individual ocular characteristics.

Supplementary Information

Below is the link to the electronic supplementary material.

Author contributions

JL, the main author, DM Yan and YL, the corresponding authors, designed the study, collected, analysed, and interpreted the data, wrote the manuscript, approved the final version of the manuscript, and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. DX collected, analysed, and interpreted the manuscript data. JL wrote the main manuscript text. All the authors have read and approved the final manuscript.

Data availability

The datasets generated and/or analysed during the current study are available from the corresponding author upon reasonable request.

Declarations

Competing interests

The authors declare no competing interests.

Ethics approval and consent to participate

The study was approved by the Lianyungang Maternal and Child Health Hospital review board (XM2023048) and was conducted in accordance with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent was obtained from at least one parent of all participating children after explanation of the nature of the study.