Association between the posterior ocular contour pattern and progression of myopia in children: A prospective study based on OCT imaging

Longitudinal changes in choroidal structures among children with low to moderate myopia under orthokeratology treatment

PURPOSE

To explore the longitudinal changes in choroidal features in myopic children with low to moderate myopia under orthokeratology (ortho-k) treatment.

METHODS

Children (n = 80) aged 8-12 years with spherical equivalent refraction of -1.00 to -6.00D were randomly assigned to the control (single vision spectacles) (n = 40) and ortho-k (n = 40) groups. OCT images were collected at the baseline, 1-, 6-, 12-, 18-, and 24-month visits. Choroidal structure parameters, including choroidal total area (TA), luminal area (LA), stromal area (SA), and choroidal vascularity index (CVI) were calculated. Axial length (AL) was measured as the primary indicator for myopic progression. The analysis followed the intention-to-treat criteria.

RESULTS

Compared to the control, ortho-k significantly improved the choroidal structures in choroidal TA and LA at all follow-up points (all P < 0.05). Choroidal LA was the primary contributor to TA changes (85.8 %[control], 91.4 %[ortho-k]), with the most significant improvement within the first 6 months. While, the changes in SA and CVI over time were not significantly different between the two groups (all P > 0.05). Correlation matrices identified several noteworthy correlations between AL change and choroidal structure features. Further analysis showed a significant interaction effect between baseline choroidal LA and intervention type on subsequent AL change (P for interaction = 0.005), suggesting that ortho-k might be more effective in children with larger baseline choroidal LA.

CONCLUSIONS

This 2-year prospective study demonstrated that ortho-k can improve the choroidal structures, primarily manifested in choroidal LA, although this positive effect diminishes over time. Myopic children with larger baseline choroidal LA might benefit more from ortho-k.

Long-term effect of orthokeratology on choroidal thickness and choroidal contour in myopic children

PURPOSE

To investigate the long-term effect of orthokeratology (ortho-k) on the choroidal thickness and choroidal contour in myopic children.

METHODS

Subjects were from a conducted 2-year randomised clinical trial. Children (n=80) aged 8-12 years with spherical equivalent refraction of -1.00 to -6.00D were randomly assigned to the control group (n=40) and ortho-k group (n=40). Optical coherence tomography images were collected at the baseline, 1-month, 6-month, 12-month, 18-month and 24-month visits, then the choroidal thickness and choroid contour were calculated. Axial length (AL) and other ocular biometrics were also measured.

RESULTS

During 2 years, in the control group, the choroidal thickness became thinning and the choroidal contour became prolate with time at all visits (all p<0.001). Ortho-k can improve the choroidal thickness (all p<0.001) and maintain the choroidal contour at all visits (all p<0.05). In the ortho-k group, the choroidal contour was less changed in the temporal than nasal (p=0.008), and the choroidal thickness was more thickening in the temporal 3 mm (p<0.001). Two-year change in choroidal thickness was significantly associated with the 2-year AL change in the control group (r=-0.52, p<0.001), however, this trend was broken by ortho-k (r=-0.05, p=0.342). After being adjusted by other variables in the multivariable regression model, the effect of ortho-k on choroidal thickness was stable.

CONCLUSIONS

In the current 2-year prospective study, ortho-k can improve the choroidal thickness and maintain the choroidal contour, but this effect diminished in a long term. Further study with larger sample size and longer follow-up is warranted to refine this issue.

Association Between Myopia and Pupil Diameter in Preschoolers: Evidence from a Machine Learning Approach Based on a Real-World Large-Scale Dataset

INTRODUCTION

Previous studies have explored the connections between various ocular biological parameters with myopia. Our previous study also found that pupil data can predict the myopic progression during the interventions for myopia. However, studies exploring the association between pupil diameter and myopia in preschoolers with myopia were lacking. Hence this study was aimed to investigate the association between pupil diameter and myopia in preschoolers with myopia based on a real-world, large-scale dataset.

METHODS

Data containing 650,671 preschoolers were collected from a total of 1943 kindergartens in Shenzhen, China. Refraction and pupil parameters were collected. After data filtering, the occurrence of myopia and its association with age, gender, pupil diameter, and other variables, were analyzed. Random forest (RF) and eXtreme gradient boosting (XGBoost) were selected from seven machine learning algorithms to build the model. The mean decrease accuracy (MDA), mean decrease Gini (MDG), and gain feature importance (GFI) techniques were employed to quantify the importance of pupil diameter and other features.

RESULTS

After the assessments, 51,325 valid records with complete pupil data were included, and 3468 (6.76%) were identified as myopia based on the calculated cycloplegic refraction. Preschoolers with myopia presented reduced pupil diameter and greater variation (5.00 ± 0.99 mm) compared to non-myopic preschoolers (6.22 ± 0.67 mm). A nonlinear relationship was found according to the scatterplots between pupil diameter and refraction (R2 = 0.14). Especially preschoolers with myopia had reduced pupil diameter compared to emmetropic preschoolers, but hyperope did not experience additional pupil enlargement. After adjusting for other covariates, this relationship is still consistent (P < 0.001). XGBoost and RF algorithms presented the highest performance and validated the importance of pupil diameter in myopia.

CONCLUSIONS

Based on a real-world large-scale dataset, the current study illuminated that preschoolers with myopia had a reduced pupil diameter compared to emmetropic preschoolers with a nonlinear pattern. Machine learning algorithms visualized and validated the pivotal role of pupil diameter in myopia.

TRIAL REGISTRATION

chictr.org Identifier: ChiCTR2200057391.