Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050

Understanding how the immune system environment is controlled in high myopia cases

High myopia (HM) is characterized by a significant extension of the eye axis; it has emerged as a serious global public health issue recently. In addition to causing severe visual impairment, HM is associated with several problems that may compromise an individual's vision. Although genetic and environmental factors in HM have been extensively investigated, increasing evidence implicates the immune system and its microenvironment in its pathogenesis. In this review, we explore the complex interactions between cytokines, immune cells, and the eye environment to elucidate the complex processes controlling the immune response in HM. Furthermore, we investigated treatments modulating the immune response and alleviating the progression of HM and its complications. Through a review of the current relevant studies, we highlight the critical functions of the immune system in the multifactorial development of HM. With the evolving understanding of the immune system's involvement in HM, this review provides a valuable resource to clinicians and researchers to develop targeted interventions and personalized treatments for individuals with this vision-threatening condition.

Development of a nomogram for predicting myopia risk among school-age children: a case-control study

OBJECTIVES

To analyze the factors influencing myopia and construct a nomogram to forecast the risk of myopia among school-age children, providing a reference for identifying high-risk groups to aid prevention and control.

METHODS

This case-control study enrolled 3512 students from three primary schools in Shenzhen using random cluster sampling for a questionnaire survey, myopia screening and ocular biometric parameter measurement. Logistic regression was used to analyze the influencing factors of myopia, and a nomogram was constructed to forecast myopia risk. Bootstrap resampling was used to verify the practicability of the nomogram.

RESULTS

Older age (odds ratio[OR] = 1.164; 95% confidence interval [CI]: 1.111-1.219), female sex (OR = 2.405; 95% CI: 2.003-2.887), maternal myopia (OR = 1.331; 95% CI: 1.114-1.589), incorrect posture during reading and writing (OR = 1.283; 95% CI: 1.078-1.528) and axial length (OR = 7.708; 95% CI: 6.044-8.288) are risk factors for myopia, whereas an increase in corneal radius (OR = 0.036; 95% CI: 0.025-0.052) is a protective factor against myopia. The area under the receiver operating characteristic (ROC) curve of the nomogram was 0.857, and the net benefit was high when the risk threshold of the decision curve analyses (DCA) ranged from 0.20 to 1.00. The measured values were consistent with the prediction.

CONCLUSION

The nomogram was accurate in predicting the risk of myopia among schoolchildren. This study provides a reference for screening high-risk students and for individualized myopia prevention and control.

The relationship between contact lens ultraviolet light transmittance and myopia progression: a large-scale retrospective cohort study

Background

The prevalence of myopia is increasing dramatically around the world, and many studies have suggested the possibility that ultraviolet (UV) light is effective to prevent the onset and progression of myopia. However, UV is a risk factor for diseases that cause refractive errors such as cataract and pterygium. In this study, we evaluated the relationship between UV exposure and myopia progression.

Methods

The dataset consisted of a total of 337 396 eyes of patients in the 12-to-29-year age range, who were prescribed soft contact lenses (SCL) for refractive error at Okada Eye Clinic in Japan between 2002 and 2011. They were tracked over a five-year period and did not change the type of SCL. In this retrospective cohort study based on medical records, we divided patients into two groups, one prescribed SCL with UV protection (UV-SCL), and another prescribed SCL without UV protection (UV + SCL).

Results

Change in refractive power over five years was measured and results compared. It was -0.413 diopter (D) in the UV-SCL group and -0.462 D in the UV + SCL group. Thus, the progression of myopia was slower in the UV-SCL group. The results were also analyzed separately by gender and degree of myopia at the time of initial prescription, which all showed significant differences (P < 0.001).

Conclusion

Results suggest that UV exposure may advance myopia. Further research is needed to investigate the underlying mechanisms that could explain this.

Animal models as windows into the pathogenesis of myopia: Illuminating new directions for vision health

The incidence of myopia, particularly high myopia, is increasing annually. Myopia has gradually become one of the leading causes of global blindness and is a considerable public-health concern. However, the pathogenesis of myopia remains unclear, and exploring the mechanism underlying myopia has become an urgent scientific priority. Creating animal models of myopia is important for studying the pathogenesis of refractive errors. This approach allows researchers to study and analyze the pathogenesis of myopia from aspects such as changes in refractive development, pathological changes in eye tissue, and molecular pathways related to myopia. This review summarizes the examples of animal models, methods of inducing myopia experimentally, and molecular signaling pathways involved in developing myopia-induced animal models. This review provides solid literature for researchers in the field of myopia prevention and control. It offers guidance in selecting appropriate animal models and research methods to fit their research objectives. By providing new insights and a theoretical basis for studying mechanisms of myopia, we detail how elucidated molecular pathways can be exploited to translate into safe and effective measures for myopia prevention and control.

Rates of Choriocapillaris Microvascular Dropout and Macular Structural Changes in Glaucomatous Optic Neuropathy With and Without Myopia

PURPOSE

To evaluate the association between rates of juxtapapillary choriocapillaris microvasculature dropout (MvD) change and rates of ganglion cell inner plexiform layer (GCIPL) loss in primary open-angle glaucoma (POAG) and glaucoma suspect eyes with and without myopia.

DESIGN

Cohort study from clinical trial data.

METHODS

238 eyes from 155 POAG and glaucoma suspect patients were stratified into no-myopia (axial length (AL) ≤ 24 mm; n = 78 eyes), mild myopia (24 mm < AL ≤ 26 mm; n = 114 eyes), and high myopia (AL > 26 mm; n = 46 eyes). Eyes with a minimum of 3 visits and 1.5 years of follow-up with both optical coherence tomography angiography (OCT-A) and OCT macula scans were included. Presence, area, and angular circumference of juxtapapillary MvD were evaluated on en face choroidal images and horizontal B-scans obtained from OCT-A imaging.

RESULTS

Over the mean follow-up of 4.4 years, the mean MvD area rates of change (95% CI) were largest in high and mild myopia group (0.04 [0.03, 0.05] mm2/year in both groups), followed by the no-myopia group (0.03 [0.02, 0.04] mm2/year). The mean MvD angular circumference rates of change (95% CI) were highest in mild myopia group (8.7° [6.9°, 10.5°]/year) followed by the high myopia and no-myopia groups (8.1° [5.3°, 10.9°]/year, and 7.4° [5.3°, 9.6°]/year, respectively). While the mean global GCIPL thinning rates between eyes with MvD at baseline compared to eyes without were similar in all myopia groups, the rates of MvD area change were significantly faster in all myopia groups with baseline MvD (all p ≤ 0.004). Significant faster rates of MvD angular circumference change were found in the mild myopia group with baseline MvD (P < .001) only. In multivariable models, the rates of GCIPL thinning over time were significantly associated with rates of MvD angular circumference change and MvD area change (R2 = 0.33, P < .001 and R2 = 0.32, P = .006, respectively).

CONCLUSIONS

Rates of GCIPL thinning were associated with rates of MvD area and angular circumference change over time in myopic POAG eyes. Utilizing OCT-A to detect MvD may provide an additional tool for monitoring macular structural changes in glaucomatous eyes with myopia.

Axial length reduction and choroidal thickening with short-term exposure to cyan light in human subjects

PURPOSE

Given the potential role of light and its wavelength on ocular growth, this study investigated the effect of short-term exposure to red, cyan and blue light on ocular biometry in humans.

METHODS

Forty-four young adults and 20 children, comprising emmetropes and myopes, underwent 2-h sessions of cyan (507 nm), red (638 nm) and broadband white light on three separate days via light-emitting glasses. Additionally, young adults were exposed to blue light (454 nm) on an additional day. Axial length (AL) and choroidal thickness (CT) were measured in the right eye before the light exposure (0 min), after 60 and 120 min of exposure and 30 min after light offset using an optical biometer and optical coherence tomographer, respectively.

RESULTS

Compared to broadband light, exposure to red light resulted in a significant increase in AL (mean difference between white and red light at 120 min, +0.007 mm [0.002]), but no significant change in CT, while cyan light caused a significant AL reduction (-0.010 mm [0.003]) and choroidal thickening (+0.008 mm [0.002]) in young adults (p < 0.05). Blue light caused a significant decrease of -0.007 mm (0.002) in young adult eyes at 60 min (p < 0.05). In children, cyan light led to a significant reduction in AL (-0.016 mm [0.004]) and strong sustained choroidal thickening (+0.014 mm [0.004]) compared to broadband light at 120 min (p < 0.05). The effects of cyan light on AL and CT were found to be stronger in myopic young adults and emmetropic children. The opposing effects of red and cyan light on ocular biometry were similar between the two age groups (p > 0.05).

CONCLUSIONS

Exposure to cyan light resulted in AL reduction and choroidal thickening in both young adults and children. Further research is needed to determine the application of these results in developing interventions for myopia control.

Effects of orthokeratology and spectacle lenses with highly aspherical lenslets on unilateral myopic anisometropia control

PURPOSE

To evaluate the 1-year effects of orthokeratology (OK) lenses and spectacle lenses with highly aspherical lenslets (HALs) on axial length (AL) elongation in children with unilateral myopic anisometropia.

METHODS

This ambispective cohort study recruited 81 children aged 8-14 years with unilateral myopic anisometropia. Of these, 42 participants (mean age 11.07 ± 1.54 years; 23 males) were treated with monocular OK lenses (OK group), and 39 (mean age 10.64 ± 1.72 years; 22 males) with binocular HALs (HAL group). Changes in AL and spherical equivalent refraction (SER) from baseline at 3, 6 and 12 months were compared between eyes and groups. Kaplan-Meier estimation and Cox proportional hazard regression were performed to analyse the risk of myopia onset in the initially non-myopic eyes.

RESULTS

Mean axial elongation in the myopic and non-myopic eyes at the 12-month follow-up visit were 0.17 ± 0.20 and 0.41 ± 0.26 mm in the OK group (p < 0.001) and 0.10 ± 0.15 and 0.12 ± 0.12 mm in the HAL group (p = 0.32), respectively. Compared with the OK group, the non-myopic eyes in the HAL group had less axial elongation, lower cumulative myopia incidence and percentage of participants with rapid myopic shift at the 6- and 12 month follow-up (all p < 0.05). Cox regression analysis showed that a higher initial SER decreased the risk of myopia onset significantly in the initially non-myopic eyes (B = -2.06; 95% CI, 0.03-0.49; p = 0.003).

CONCLUSIONS

Monocular OK lenses suppressed axial elongation in the myopic eye and minimised anisometropia; however, the non-treated contralateral eye may experience faster myopia onset and myopic shift. Binocular HALs can effectively reduce axial elongation in both eyes of children with unilateral myopic anisometropia.

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.

Can we really distinguish 'responders' from 'non-responders' to myopia control interventions?

PURPOSE

It is common to hear talk of 'responders' and 'non-responders' with respect to myopia control interventions. We consider the reality of distinguishing these sub-groups using data from the first year of the Low-concentration Atropine for Myopia Progression (LAMP) study.

METHODS

The first year of the LAMP study was a robustly designed, placebo-controlled trial of three different low concentrations of atropine using a large sample size (N > 100 randomised to each group). The authors subsequently published mean axial elongation and myopia progression rates by age group. We used these data to calculate efficacy in terms of both absolute reduction in myopic progression and absolute reduction in axial elongation for each of the different atropine concentrations at each age group. We then compared these efficacy data to the overall progression for each of the two progression metrics.

RESULTS

Plotting efficacy as a function of overall myopia progression and axial elongation for each of the different atropine concentrations demonstrates the invariant nature of efficacy, in terms of clinically meaningful reduction in progression, despite a substantial range of underlying overall progression. That is, faster progressors-the so-called non-responders-achieved similar reduction in axial elongation and myopia progression as the slower progressors-the so-called responders-within the various atropine treatment groups.

CONCLUSION

The use of the terms, responders and non-responders, during myopia progression interventions is not supported by evidence. Those designated as such may simply be slower or faster progressors, who, on average achieve the same benefit from treatment.

A Novel Time-Aware Deep Learning Model Predicting Myopia in Children and Adolescents

Objective

To quantitatively predict children's and adolescents' spherical equivalent (SE) by leveraging their variable-length historical vision records.

Design

Retrospective analysis.

Participants

Eight hundred ninety-five myopic children and adolescents aged 4 to 18 years, with a complete ophthalmic examination and retinoscopy in cycloplegia prior to spectacle correction, were enrolled in the period from January 1, 2008 to July 1, 2023 at the University Hospital "Sveti Duh," Zagreb, Croatia.

Methods

A novel modification of time-aware long short-term memory (LSTM) was used to quantitatively predict children's and adolescents' SE within 7 years after diagnosis.

Main Outcome Measures

The utilization of extended gate time-aware LSTM involved capturing temporal features within irregularly sampled time series data. This approach aligned more closely with the characteristics of fact-based data, increasing its applicability and contributing to the early identification of myopia progression.

Results

The testing set exhibited a mean absolute prediction error (MAE) of 0.10 ± 0.15 diopter (D) for SE. Lower MAE values were associated with longer sequence lengths, shorter prediction durations, older age groups, and low myopia, while higher MAE values were observed with shorter sequence lengths, longer prediction durations, younger age groups, and in premyopic or high myopic individuals, ranging from as low as 0.03 ± 0.04 D to as high as 0.45 ± 0.24 D.

Conclusions

Extended gate time-aware LSTM capturing temporal features in irregularly sampled time series data can be used to quantitatively predict children's and adolescents' SE within 7 years with an overall error of 0.10 ± 0.15 D. This value is substantially lower than the threshold for prediction to be considered clinically acceptable, such as a criterion of 0.75 D.

Financial Disclosures

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

Progression Patterns and Risk Factors of Axial Elongation in Young Adults With Nonpathologic High Myopia: Three-Year Large Longitudinal Cohort Follow-Up

PURPOSE

To investigate the progression patterns and risk factors of axial elongation in young adults with nonpathologic high myopia.

DESIGN

Prospective, clinical observational cohort study with 2- to 4-year follow-up.

METHODS

A total of 1043 eyes of 563 participants (3515 medical records) aged 18 to 50 years with nonpathologic high myopia (axial length [AL] ≥ 26 mm; myopic maculopathy < diffuse chorioretinal atrophy; without posterior staphyloma) were included from 1546 participants (6318 medical records). Annual axial elongation was calculated via linear mixed-effect models. The associated risk factors of axial elongation were determined by ordinal logistic regression analysis, with generalized estimate equations for eliminating an interocular correlation bias.

RESULTS

Based on 5359 times of AL measurements, the annual axial elongation of participants (mean [SD] age 31.39 [9.22] years) was 0.03 mm/year (95% confidence interval [CI], 0.03-0.04; P < .001) during a 30.23 (6.06) months' follow-up. Severe (>0.1 mm/year), moderate (0.05-0.09 mm/year), mild (0-0.049 mm/year), and nil (≤0 mm/year) elongation was observed in 122 (11.7%), 211 (20.2%), 417 (40.0%), and 293 (28.1%) eyes. The following risk factors were significantly associated with axial elongation: baseline AL ≥ 28 mm (odds ratio [OR], 4.23; 95% CI, 2.95-6.06; P < .001); age < 40 years (OR, 1.64; 95% CI, 1.18-2.28; P = .003); axial asymmetry (OR, 2.04; 95% CI, 1.26-3.29; P = .003), and women (OR, 1.52; 95% CI, 1.13-2.2.05; P = .006). Using antiglaucoma medications was a protective factor (OR, 0.46; 95% CI, 0.27-0.79; P = .005), which slowed 75% of axial elongation from 0.04 (0.06) to 0.01 (0.06) mm/y (P < .001).

CONCLUSIONS

Axial elongation continued in young adults with nonpathologic myopia. Risk factors included longer baseline AL and axial asymmetry, younger age, and woman. Topical use of antiglaucoma medications may be useful to reduce ongoing axial elongation.

Animal modeling for myopia

Background

Myopia is one of the most common eye diseases globally, and has become an increasingly serious health concern among adolescents. Understanding the factors contributing to the onset of myopia and the strategies to slow its progression is critical to reducing its prevalence.

Main text

Animal models are key to understanding of the etiology of human diseases. Various experimental animal models have been developed to mimic human myopia, including chickens, rhesus monkeys, marmosets, mice, tree shrews, guinea pigs and zebrafish. Studies using these animal models have provided evidences and perspectives on the regulation of eye growth and refractive development. This review summarizes the characteristics of these models, the induction methods, common indicators of myopia in animal models, and recent findings on the pathogenic mechanism of myopia.

Conclusions

Investigations using experimental animal models have provided valuable information and insights into the pathogenic mechanisms of human myopia and its treatment strategies.

Visual impact of diffusion optic technology lenses for myopia control

PURPOSE

To assess the visual impact of Diffusion Optics Technology™ 0.2 DOT lenses (SightGlass Vision Inc.) designed for myopia control on primary gaze. DOT spectacle lenses contain light scattering elements that scatter light as it passes through the lens which, in turn, reduces retinal image contrast.

METHODS

Fifty-one children (12.2 ± 1.3, range 10-14 years; 51% females) were randomly assigned to wear DOT spectacle (n = 27) or single vision lenses (n = 24) across six investigational sites in North America. Binocular high- and low-contrast distant visual acuities, near visual acuity, reading speed, contrast sensitivity, stereoacuity and glare were assessed in primary gaze after at least 3 years of wear, with the study 95% powered in all metrics to detect significant differences between the groups.

RESULTS

Mean binocular distance high-contrast (-0.09 ± 0.02 vs. -0.08 ± 0.02 logMAR, p = 0.81), low-contrast (0.05 ± 0.02 vs. 0.07 ± 0.02 logMAR, p = 0.52) and near visual acuity with glare sources (-0.06 ± 0.03 vs. -0.09 ± 0.03 logMAR, p = 0.32) were similar for DOT and single vision lens wearers, respectively. Contrast sensitivity was similar between children wearing DOT or single vision lenses across 11 of the 16 spatial frequencies (p > 0.05). Mean stereopsis was similar (p = 0.30) with the DOT lenses (33.2 ± 12.5″) and single vision lenses (38.1 ± 14.2″). Functional reading speed metrics were similar in both study groups, as was the objectively measured head tilt during reading (p > 0.05). The mean halo radius was 0.56° ± 0.17° with the DOT lenses compared with 0.50° ± 0.12° with single vision lenses (p = 0.02), but the statistically significant difference was smaller than the non-inferiority bound of 0.4°.

CONCLUSION

Diffusion optics technology lenses provide a clinically equivalent visual experience to a standard single vision lens.

Artificial intelligence in myopia in children: current trends and future directions

PURPOSE OF REVIEW

Myopia is one of the major causes of visual impairment globally, with myopia and its complications thus placing a heavy healthcare and economic burden. With most cases of myopia developing during childhood, interventions to slow myopia progression are most effective when implemented early. To address this public health challenge, artificial intelligence has emerged as a potential solution in childhood myopia management.

RECENT FINDINGS

The bulk of artificial intelligence research in childhood myopia was previously focused on traditional machine learning models for the identification of children at high risk for myopia progression. Recently, there has been a surge of literature with larger datasets, more computational power, and more complex computation models, leveraging artificial intelligence for novel approaches including large-scale myopia screening using big data, multimodal data, and advancing imaging technology for myopia progression, and deep learning models for precision treatment.

SUMMARY

Artificial intelligence holds significant promise in transforming the field of childhood myopia management. Novel artificial intelligence modalities including automated machine learning, large language models, and federated learning could play an important role in the future by delivering precision medicine, improving health literacy, and allowing the preservation of data privacy. However, along with these advancements in technology come practical challenges including regulation and clinical integration.

Clinical Investigation of Short-Term Axial Elongation Control After Orthokeratology Lens Correction: Exploring Its Predictive Role in Long-Term Therapeutic Efficacy

OBJECTIVE

This study was developed with the goal of exploring the efficacy of orthokeratology (OK) as an approach to controlling axial length (AL) growth and identifying factors predictive of the long-term efficacy of this approach.

METHODS

This was a retrospective study that enrolled 157 myopic children 7 to 15 years of age undergoing OK correction for over 3 years. The short- and long-term effectiveness of this approach at 1 and 3 years post-OK correction, respectively, was assessed. All participants were classified into two groups based on whether they exhibited good or poor long-term efficacy outcomes. Measurements of changes in AL were made at baseline and at 1 and 3 years post-OK. Univariate analyses and binary logistic regression approaches were used to evaluate baseline age, baseline spherical equivalent refraction, baseline keratometry (K) values of flat and steep meridians, and short-term effectiveness with the goal of identifying predictors of long-term efficacy.

RESULTS

Univariate analyses led to the identification of significant differences in baseline age, baseline spherical equivalent refraction, baseline AL, and short-term efficacy between these two groups (P<0.05), whereas gender, baseline flat K, and baseline steep K did not differ significantly (P>0.05). In binary logistic regression analyses, baseline AL (P=0.017) and short-term efficacy (P<0.001) were both found to significantly influence long-term efficacy. Receiver operating characteristic curves demonstrated that short-term efficacy offered an area under the curve value >0.8, consistent with its highly accurate performance as a predictor of long-term efficacy.

CONCLUSION

These results suggest that short-term efficacy outcomes can feasibly be used to predict the long-term effectiveness of OK correction in children. In patients exhibiting poor short-term efficacy, timely replacement or the incorporation of additional treatment modalities may aid efforts to better control the progression of myopia.

Observations on relative peripheral refraction in Chinese adults with myopia based on a novel application of multispectral refraction topography

In this population-based observational cross-sectional study, we investigated retinal peripheral refraction in Chinese adults with myopia. We categorized 1511 Chinese adults with myopia (18 - 55 years) into low (LM), moderate (MM), and high myopia (HM) groups. Axial length, central corneal thickness, steep keratometry, flat keratometry, and intraocular pressure were measured. Refractive difference values (RDVs) for different eccentricities (RDV0-53) and the superior (RDV-S), inferior (RDV-I), temporal (RDV-T), and nasal (RDV-N) retinal regions were measured using multispectral refractive topography. The hyperopic defocus was higher for the MM group than for the LM group in RDV20-53, RDV-S, and RDV-T and HM group in RDV20-53, RDV-S, RDV-T and RDV-N. The hyperopic defocus was higher for the HM group than for the LM group in RDV20-53, RDV-S and RDV-T but lower for the LM group in RDV-N. RDV-N decreased with age (R2 = 0.0191, slope = - 0.01, p < 0.0001), whereas RDV-S (R2 = 0.0112, slope = 0.01,p < 0.0001) and RDV-T increased (R2 = 0.0038, slope = 0.01, p = 0.0160). RDV correlated with central spherical equivalent and axial length. Flat keratometry explained the most RDV variation (RDV20-30: β = 0.0714, p < 0.0001; RDV-N: β = 0.1801, p < 0.0001; RDV-S: β = 0.1426, p < 0.0001; RDV-T: β = 0.1239, p < 0.0001). Reference values for peripheral retinal defocus are provided for Chinese adults with different myopia ranges.

Knowledge, attitude and the associated factors regarding spectacle use among adults living in Debre Birhan Town, North Shewa, Ethiopia, 2023: a community-based, cross-sectional study

OBJECTIVE

This study aimed to assess the knowledge, attitude and the associated factors regarding spectacle use among adults living in Debre Birhan Town, North Shewa, Ethiopia.

DESIGN

A community-based, cross-sectional study was conducted using a multistage sampling method.

SETTING

The study was conducted in Debre Birhan Town, North Shewa, Ethiopia.

PARTICIPANTS

The study included 1022 adults aged ≥18 years living in Debre Birhan Town for more than 6 months.

MAIN OUTCOME MEASURES

Data were collected using face-to-face interviews completed by an interviewer.

RESULTS

The study included 1022 adults with a median age of 45 years. Of the participants, 86.01% (95% CI 83.88, 88.14) had adequate knowledge and 85.32% (95% CI 83.15, 87.50) had favourable attitude towards spectacle use. Older age (adjusted OR (AOR)=1.21, 95% CI 1.17, 1.26), higher educational status (AOR=2.65, 95% CI 1.06, 6.60), history of spectacle use (AOR=3.20, 95% CI 1.31, 7.83) and family history of spectacle use (AOR=4.75, 95% CI 2.31, 9.75) were positively associated with having adequate knowledge of spectacle use. Higher educational status (AOR=2.56, 95% CI 1.26, 5.21), history of spectacle use (AOR=3.22, 95% CI 1.58, 6.55), family history of spectacle use (AOR=1.89, 95% CI 1.13, 3.16) and adequate knowledge about spectacle use (AOR=4.63, 95% CI 2.69, 7.98) were positively associated with having favourable attitude towards spectacle use.

CONCLUSION

This study revealed a good proportion of adults with adequate knowledge and favourable attitude towards spectacle use. Higher educational status, history of spectacle use and family history of spectacle use were significantly associated with having adequate knowledge and favourable attitude towards spectacle use.

Association between weekend catch-up outdoor duration and prevalence of myopia: evidence from a cross-sectional, multi-center study in China

BACKGROUND

This study aimed at investigating the relationship between the weekend catch-up outdoor duration (WCOD) and prevalence of myopia among students in China.

METHODS

This cross-sectional study recruited participants in 107 schools (six cities, 30 districts) from China from May to June 2021. Demographic characteristics (age, grade, sex, ethnicity, BMI, resident, and parents' myopia), optically habits (bad writing habits, working/studying time per day, continuous working/studying time per day, and screen time per day) and outdoor duration (weekday and weekend) were obtained from questionnaire. WCOD was defined as outdoor time 1 h longer on weekends than on weekdays. Spherical equivalent (SE) of refractive error were measured with non-cycloplegic refraction. Adjusted multivariate logistic regression analysis was performed to evaluate the relationship between WCOD and prevalence of myopia.

RESULTS

Students with myopia had shorter WCOD compared with those without myopia (P < 0.001). Adjusted multivariate logistic regression analyses showed negative associations between WCOD and prevalence of myopia in Chinese students, especially in students with WCOD of 2-3 h (OR = 0.577, P < 0.001) and 3-4 h (OR = 0.571, P = 0.004) when the weekday outdoor duration was 0.5-1 h, as well as students with WCOD of 2-3 h (OR = 0.614, P = 0.003) when the weekday outdoor duration was 1-2 h. Similar results were observed in students with high myopia. Students with high myopia had shorter WCOD compared with those without high myopia (P = 0.001). Negative associations between WCOD and prevalence of high myopia were significant in students with WCOD of 1-2 h when the weekday outdoor duration was < 0.5 h (OR = 0.585, P = 0.007) and 0.5-1 h (OR = 0.537, P = 0.018).

CONCLUSION

Our study, for the first time, reported that a WCOD have a potential to reduce the prevalence of myopia and high myopia in Chinese students.

Distribution and associated factors of choroidal thickness in highly myopic eyes-a real-world study based on a Chinese population

PURPOSE

To measure the subfoveal choroidal thickness (SFCT) in highly myopic eyes at different locations using enhanced depth imaging spectral-domain optical coherence tomography (EDI SD-OCT). To identify the ocular and systemic risk factors associated with choroidal thinning in high myopia.

METHODS

Based on the Beijing Eye Study, a detailed ophthalmic examination was performed including EDI SD-OCT for the measurement of SFCT. OCT images were obtained from 103 highly myopic eyes (≥ -6.00 dioptres) and 227 normal eyes randomly selected from the baseline population, matched for age and sex.

RESULTS

The mean SFCT was 110.6 ± 85.2 μm in highly myopic eyes (range, 3-395 μm). Mean regional choroidal thickness was lowest on the nasal and inferior sides of the macula, and slightly higher on the temporal and superior sides than at the fovea. On multivariate analysis, SFCT was associated with age (b = -0.48; P < 0.001), axial length (b = -0.44; P < 0.001), gender (b = -0.31; P < 0.05) and staphyloma (b = -0.26; P = 0.05). In highly myopic eyes, SFCT decreased by 5.1 μm/year of age, by 9.2 µm/D of myopia, and by 22.6 µm/mm of axial length.

CONCLUSIONS

The SFCT decreases with age and increased axial length in highly myopic eyes. The formation of a posterior staphyloma has been identified as a major contributor to choroidal thinning and is therefore a reliable indicator for risk management. The involvement of choroidal abnormalities may be a significant factor in the development of myopic degeneration.

One-year efficacy of myopia control by the defocus distributed multipoint lens: a multicentric randomised controlled trial

AIMS

To report the 1-year results of the efficacy of a defocus distributed multipoint (DDM) lens in controlling myopia progression in a multicentre, randomised controlled trial.

METHODS

Overall, 168 children aged 6-13 years were recruited and randomly assigned to wear a DDM lens (n=84) or single-vision (SV) lens (n=84) in three centres. Cycloplegic autorefraction (spherical equivalent refraction (SER)) and axial length (AL) were measured. Linear mixed model analysis was performed to compare between-group SER and AL changes. Logistic regression analysis was used to analyse the between-group difference in rapid myopia progression (SER increase≥0.75 D per year or AL growth≥0.40 mm per year).

RESULTS

After 1 year, mean changes in SER were significantly lower in the DDM group (-0.47±0.37 D) than in the SV group (-0.71±0.42 D) (p<0.001). Similarly, mean changes in AL were significantly lower in the DDM group (0.21±0.17 mm) than in the SV group (0.34±0.16 mm) (p<0.001). After adjusting for age, sex, daily wearing time and parental myopia, rapid myopia progression risk was higher in the SV group than in the DDM group (OR=3.51, 95% CI: 1.77 to 6.99), especially for children who wore a lens for >12 hours per day, boys and younger children (6-9 years) with ORs (95% CIs) of 10.82 (3.22 to 36.37), 5.34 (1.93 to 14.78) and 8.73 (2.6 to 29.33), respectively.

CONCLUSIONS

After 1 year, DDM lenses effectively retarded myopia progression in children. Longer daily wearing time of DDM lens improved the efficacy of myopia control. Future long-term studies are needed for validation.

TRIAL REGISTRATION NUMBER

NCT05340699.

Choriocapillaris flow features in children with myopic anisometropia

AIMS

To examine differences between the eyes in choriocapillaris perfusion and choroidal thickness in children with myopic anisometropia.

METHODS

In this observational and prospective study, 46 children with myopic anisometropia were enrolled. Choriocapillaris perfusion parameters, including the percentage of flow voids, the total number of flow voids and the average flow void area were obtained by optical coherence tomography angiography (OCTA). The OCTA image was divided into a 1 mm-diameter central circle (C1) and a 2.5 mm-diameter annulus (without the inner central 1 mm circle, C1-2.5). Both C1 and C1-2.5 are centred on the foveola. The C1-2.5 was divided into nasal (N1-2.5), temporal (T1-2.5), inferior (I1-2.5) and superior (S1-2.5) areas. Differences in these parameters in different regions between eyes were analysed.

RESULTS

There were no significant differences in the percentage of flow voids and the average flow void area between the fellow eyes. The total number of signal voids was significantly higher in the less myopic eyes in C1-2.5 (p=0.032), S1-2.5 (p=0.008) and N1-2.5 (p=0.019). Changes in spherical equivalent refraction and axial length were both correlated with the changes in the total number of flow voids in N1-2.5 (R=-0.431, p=0.03; R=-0.297, p=0.047).

CONCLUSIONS

The choroid in the macular region becomes thinner and the total number of flow voids in the nasal macular region decreased with the amplitude of myopia. This suggests that a decrease in total number of flow voids may indicate an early change in myopia.

Prevalence and risk factors of myopia among children and adolescents in Hangzhou

To analyze the prevalence and influencing factors of myopia among children and adolescents in Hangzhou city, and provide ideas for the formulation of myopia prevention and control measures. A cross-sectional school-based study using stratified cluster random sampling method was used to select 31,880 students from 113 schools in Hangzhou city. Myopia screening and questionnaires on the influencing factors of poor visual acuity were carried out. Univariate and multivariate logistic regression were used to screen possible risk factors of myopia. The overall prevalence of myopia was found to be 55.3% (17,630/31,880), with the myopia rates observed among students in kindergarten, primary school, junior high school, and senior high school, at 5.8%, 34.9%, 74.2%, and 85.0%, respectively. As the academic year progresses, there has been an observable increase in the prevalence of myopia (χ2 = 8676.748, P<0.001), low myopia (χ2 = 5444.040, P<0.001) and high myopia (χ2 = 2171.073, P<0.001) among students, with the difference between the three groups being statistically significant. The myopia prevalence in girls is higher than that in boys (χ2 = 119.917, P<0.001); the prevalence of myopia in urban students is higher than that in suburban students (χ2 = 4.603, P = 0.032). The time spent on homework after school, the correctness of reading and writing postures, the duration of exposure to electronic screens, and the use of lighting in an appropriate manner all have an impact on the development of myopia (all P<0.05). The overall prevalence of myopia and high myopia in schools in eastern China, is notably high. The prevalence of myopia and high myopia increases with grade or age. Myopia is associated with increased age, parental myopia, extended periods of homework after school, poor reading and writing posture, prolonged exposure to electronic screens and inappropriate lighting. In light of the findings of the present survey, it is recommended that a comprehensive prevention and control intervention model for myopia in children and adolescents based on society-hospital-school-family-individual students with a view to preventing and controlling myopia.

Efficacy of Posterior Scleral Reinforcement in Treating Anisometropic Amblyopia Associated With Unilateral High Myopia in Children

The aim of this study is to examine the effectiveness and safety of posterior scleral reinforcement (PSR) for treating anisometropic amblyopia and myopia associated with high myopia in children. Children with unilateral high myopia (uHM) and anisometropic amblyopia who underwent PSR in their highly myopic eyes were included in this study. The treated eye was designated as the PSR group, whereas the healthier eye served as the control, and paired comparisons were made. Thirteen patients (13 eyes in each group) were included, with an average age of 5.85±2.08 years. Cross-sectional comparisons between the groups showed that within 2 to 3 years after surgery, the PSR group had a significantly greater increase in best-corrected visual acuity per month compared with the control group (P=0.03), a significantly lower increase in axial length per month (P=0.007), and a significantly smaller absolute value of the increase in SE per month (P=0.002). Temporal longitudinal comparisons within the PSR group indicated that the increase in axial length per month 2 to 3 years after surgery was significantly slower than 1 year before surgery (P=0.045). The increase in best-corrected visual acuity per month was higher than 1 year before surgery, although not significantly (P=0.859). PSR is a safe and effective treatment for refractory anisometropic amblyopia caused by uHM, and for controlling axial length and the degree of myopia.

Association between axial length and uveitis

PURPOSE

Multiple studies have examined the association between myopia and various ocular diseases, but there is no clinical report of the relationship between myopia and uveitis. This study aimed to elucidate the relationship between myopia and uveitis by comparing axial lengths (AL) of uveitis patients with control individuals.

METHODS

This study included 1052 eyes (663 patients; 288 males, 375 females; median age 56.0 years) with uveitis referred to Tokyo Medical University Hospital. Controls were 738 eyes with cataract but no other ocular diseases. AL was measured by IOLMaster or conventional A-mode ultrasound system. Uveitis eyes were grouped into various types of non-infectious uveitis, infectious uveitis, and unidentified uveitis. Median AL of each uveitis group was compared with control group using Mann-Whitney U-test, and also compared with adjustment for age and sex using multiple regression analysis. Binary logistic analysis was performed to examine whether AL plays a role in the risk of developing uveitis.

RESULTS

Of 1052 eyes, 808 eyes (76.8%) were diagnosed with non-infectious uveitis [sarcoidosis (176 eyes, 16.7%), Vogt-Koyanagi-Harada disease (122 eyes, 11.6%), Behçet's disease (130 eyes, 12.4%), and others (380 eyes, 36.1%)], 146 eyes (13.9%) with infectious uveitis, and 98 eyes (9.3%) with unidentified uveitis. Median AL in all uveitis eyes was significantly shorter than in control eyes (23.73 vs 24.31 mm, p < 0.001 unadjusted), and AL remained significantly shorter in uveitis than in control after age- and sex-adjustment (p < 0.001). Median AL was significantly shorter in non-infectious uveitis (23.72 mm) and in infectious uveitis (23.99 mm) compared to controls (p < 0.001 and < 0.05, respectively), and was significantly shorter in non-infectious uveitis than in infectious uveitis (p < 0.05). Each millimeter decrease in AL was associated with 1.266-fold increase in unadjusted risk [odds ratio (OR), 1.266; 95% confidence interval (CI), 1.196-1.341; p < 0.001) and 1.446-fold in age- and sex-adjusted risk (OR, 1.446; 95% CI, 1.349-1.549; p < 0.001) of developing uveitis.

CONCLUSION

Median AL of uveitis eyes with infectious or non-infectious etiologies was significantly shorter than that in control eyes, suggesting an increased risk of developing uveitis in eyes with shorter AL. This feature should be considered when exploring new pathogenetic mechanisms of uveitis.

KEY MESSAGES

What is known Shorter axial length may be associated with the pathogenesis of central serous chorioretinopathy and increased risk of early age-related macular degeneration. What is new Here we assessed the relationship between myopia and uveitis by comparing axial lengths of uveitis patients. Median axial length in all uveitis eyes was significantly shorter than in control eyes, and axial length remained significantly shorter in uveitis than in control after age- and sex-adjustment. Each millimeter decrease in axial length was associated with 1.266-fold increase in unadjusted risk and 1.446-fold in age- and sex-adjusted risk of developing uveitis.

Macular Buckling for Myopic Traction Maculopathy: A Comprehensive Systematic Review and Meta-Analysis

PURPOSE

Myopic traction maculopathy is a major cause of visual impairment and blindness, particularly in Asian populations. With the global burden of myopia on the rise, understanding effective treatment options is crucial. This systematic review and meta-analysis evaluate the efficacy of macular buckling in the management of myopic traction maculopathy.

DESIGN

A systematic review and meta-analysis.

METHODS

A systematic review and meta-analysis were conducted following PRISMA guidelines. PubMed, Cochrane Library, and EMBASE databases were searched for relevant studies up to July 2024. Inclusion criteria encompassed studies reporting outcomes of macular buckling for myopic traction maculopathy. Primary outcomes included changes in best-corrected visual acuity (BCVA) and axial length, retinal reattachment rate, and macular hole closure rate. Random-effect models were used for statistical analysis, with heterogeneity assessed using the I² statistic. The pooled results were reported as mean difference or proportion with corresponding 95% confidence intervals (CI) for each outcome.

RESULTS

Thirteen studies (482 eyes) met the inclusion criteria. Significant improvements in BCVA were observed across all follow-up periods, with the most substantial improvement in long-term outcomes (mean difference: 0.38 logMAR; 95% CI: 0.28 to 0.47). Axial length showed consistent reductions, with a mean long-term reduction of 2.88 mm (95% CI: 2.54 to 3.21). The pooled long-term retinal reattachment rate was 94% (95% CI: 86-97%), while the long-term full thickness macular hole closure rate was 72% (95% CI: 55-85%). Heterogeneity varied across outcomes and follow-up periods, ranging from low to high.

CONCLUSION

Macular buckling demonstrates promising outcomes for myopic traction maculopathy, including improved visual acuity, reduced axial length, high retinal reattachment rates, and favorable macular hole closure rates. These findings support the efficacy of macular buckling as a treatment option for myopic traction maculopathy. However, further standardized, long-term studies are needed to confirm these results and explore potential combination therapies.

Privacy Preserving Technology using Federated Learning and Blockchain in protecting against Adversarial Attacks for Retinal Imaging

PURPOSE

Collaboration provides valuable data for robust artificial intelligence (AI) model development. Federated learning (FL) is a privacy enhancing technology that allows collaboration while respecting privacy via the development of models without raw data transfer. However state-of-the-art FL models still face challenges in non-independent and identically distributed (non-i.i.d.) health care settings and remain susceptible to privacy breaches. We propose a novel FL framework coupled with blockchain technology to address these challenges.

DESIGN

Retrospective multicohort study SUBJECTS AND METHODS: 27,145 images from Singapore, China and Taiwan were used to design a novel FL aggregation method for the detection of myopic macular degeneration (MMD) from fundus photographs and macular disease from optical coherence tomography (OCT) scans in feature distribution skew and label distribution imbalance scenarios. We further performed adversarial attacks (label flipping and clean label). As proof of concept, blockchain was incorporated into FL to demonstrate secure transfer of model updates across collaborating sites.

MAIN OUTCOME MEASURES

We evaluated our FL model performance in MMD and OCT classification and compared our model against state-of the-art FL and centralized models.

RESULTS

Our FL model showed robust performance with areas under the receiving operating characteristic curves (AUC) of 0.868±0.009 for MMD detection and 0.970±0.012 for OCT macular disease classification. In label flipping attack, our FL model had an AUC of 0.861±0.019, similar to the centralized model (AUC 0.856± 0.015) and higher than other FL models (AUC 0.578-0.819) In clean label attack, our FL model had an AUC of 0.878±0.006 which was comparable to the centralized model (AUC 0.878±0.001) and superior to other state-of-the-art FL models with AUC of 0.529-0.838. Simulation showed that the additional time with blockchain in one global epoch was around 5 seconds. The addition of blockchain to the FL framework was feasible with a minimal impact on model development time.

CONCLUSIONS

Our proposed FL algorithm overcomes the shortcoming of the traditional FL in non i.i.d. situations and remains robust to against adversarial attacks. The integration of blockchain adds further security during the transfer of model updates. Blockchain-enabled FL can be a trusted platform for collaborative health AI research.

Effect of 0.01% atropine eye drops combined with different optical treatments to control low myopia in Chinese children

PURPOSE

To investigate the efficacy and safety of 0.01% atropine (AT) in combination with different optical treatments for controlling myopia in Chinese children.

METHODS

This retrospective study analyzed 341 Chinese children aged 6-11 years with myopia between -0.50 D and -3.0 D between January 2022 and May 2023. The fast-progressing, myopic children received three optical treatments combined with 0.01 % atropine: 75 children with single-vision spectacles and atropine (SV + AT), 162 children with defocus-incorporated multi-segment spectacles and atropine (DIMS + AT), or 104 children with orthokeratology and atropine (OK + AT). The changes in spherical equivalent refraction (SER), axial length (AL), intraocular pressure (IOP), and amplitude of accommodation (AMP) were observed at 6-month and 1-year intervals.

RESULTS

After controlling for baseline variables, at 6 months, the increase in adjusted AL was significantly greater in the SV + AT group than in the DIMS + AT group (difference = 0.13 mm, 95 % CI: 0.07-0.20, P < 0.05) and in the OK + AT group (difference = 0.09 mm, 95 % CI: 0.09-0.17, P < 0.05). A more significant progression in adjusted SER was also observed in the SV + AT group than in the DIMS group (difference = -0.20D, 95 % CI: -0.29 to -0.11, P < 0.05). At 12 months, the greatest increase in adjusted AL was observed in the SV + AT group, with a statistically significant difference of 0.24 mm (95 % CI: 0.19-0.29, P < 0.05) compared with the DIMS group and a difference of 0.19 mm (95 % CI: 0.13-0.25, P < 0.05) compared with the OK + ST group. Similarly, a more significant progression in adjusted SER was observed in the SV + AT group than in the DIMS group (difference = -0.36 D, 95 % CI: -0.48 to -0.24, P < 0.05).

CONCLUSIONS

This study suggested that 0.01% atropine combined with DIMS or orthokeratology may be viable for controlling low myopia in fast-progressing, myopic children.

Refractive error and ocular alignment in school-aged children from low-income areas of São Paulo, Brazil

BACKGROUND

Uncorrected refractive errors and amblyopia are reported as the two main causes of childhood visual impairment and blindness worldwide. Our purpose was to evaluate refractive status, ocular alignment and effective refractive error coverage (eREC) of school-aged children from low-income areas of Sao Paulo city, Brazil.

METHODS

Data from the "Ver na Escola" Project were used for the current study. Children enrolled in the selected schools had an ophthalmic exam including eye alignment assessed by cover test, automatized and subjective dynamic and static refraction. The associations of demographic variables with occurrence and magnitude of refractive errors and eREC were investigated by multiple logistic regressions and multilevel mixed effect models.

RESULTS

A total of 17,973 children (51.12% females) with mean ± sd age 8.24 ± 3.54 years old examined from July 2018 to July 2019, were included in the study. Most of the participants (73%) showed orthoposition of the visual axis for both distance and near. Heterophoria was found in about 25% of participants (N = 4,498), with 71.7% of them (N= 3,222) classified as exophoria. Less than 2% (N = 232) showed strabismus, most of them (N = 160) esotropia. Overall, 1,370 (7.70%) of participants had myopia and 577 (3.24%) had hyperopia. Age was found to be significantly associated with increasing static subjective refraction spherical equivalent (Coefficient: -0.18; 95% Confidence Interval (CI): -0.21 to -0.16; p < 0.001). Female sex (Odds Ratio (OR) = 1.13; 95%CI: 1.01-1.27; p = 0.027) and older age (OR = 1.17; 95%CI: 1.16-1.19; p < 0,001) were significantly associated with myopia diagnosis. Older age decreased the odds of hyperopia (OR = 0.95; 95%CI: 0.93-0.98; p < 0.001). The overall effective refractive coverage was 51.76% and was significantly associated with age group, ranging from 32.25% in children aged 3 to 7 years to 61.35% in children aged 8 to 12 years.

CONCLUSIONS

Most children have shown eye alignment for both distance and near assessments and no refractive error. Myopia was observed in 7.70% of the population and it was associated with older age and female sex. Hyperopia was observed in 3.24% and was associated with younger age. The overall eREC was 51.76%, significantly associated with age.

Impact of back optic zone diameter (BOZD) in orthokeratology on axial length elongation: A meta-analysis and systematic review

PURPOSE

Myopia has emerged as a significant public health concern. Recent studies have demonstrated that Orthokeratology (Ortho-K) can effectively decelerate axial length (AL) growth, with eyes possessing smaller back optical zone diameters (BOZD) exhibiting greater effectiveness compared to those with larger BOZD. This study aims to analyze the impact of Ortho-K with varying BOZD.

METHOD

This systematic review involved the retrieval of articles from eight databases: PubMed, Embase, Web of Science, Cochrane, CNKI, Wanfang, Sinomed, and VIP, covering the period from each database's inception to January 2024. It compared axial length (AL) changes between smaller and larger back optic zone diameters (BOZD). Review Manager 5.4 was used to statistical analysis and the results presented as weighted mean differences and 95% confidence intervals (CI). This review adheres to the PRISMA guidelines.

RESULT

This systematic review included two randomized controlled trials (RCTs) and five cohort studies (CS), analyzing a total of 702 eyes (352 eyes are treated with Ortho-K and BOZD ≤ 5.5 mm, 350 eyes are treated with Ortho-K and BOZD ≥ 6.0 mm). The findings indicate that the Ortho-K with smaller BOZD significantly reduces AL growth [WMD = -0.13, 95 %CI (-0.16 to -0.10), P < 0.001].

CONCLUSION

The Ortho-K with smaller BOZD prove more effective in controlling myopic AL growth compared with larger BOZD. However, in clinical practice, it is necessary to comprehensively evaluating factors such as patient age, myopia diopter, pupil diameter, higher-order aberration, treatment zone area, and corneal eccentricity to achieve optimized outcomes in improving naked-eye vision and myopia controlling.

Proteomic analysis of CD29+ Müller cells reveals metabolic reprogramming in rabbit myopia model

The prevalence of myopia is rapidly increasing, significantly impacting the quality of life of affected individuals. Prior research by our group revealed reactive gliosis in Müller cells within myopic retina, prompting further investigation of their role in myopia, which remains unclear. In this study, we analyzed protein expression changes in CD29+ Müller cells isolated from a form deprivation-induced rabbit model of myopia using magnetic activated cell sorting to investigate the role of these cells in myopia. As the principal glial cells in the retina, Müller cells exhibited significant alterations in the components of metabolic pathways, particularly glycolysis and angiogenesis, including the upregulation of glycolytic enzymes, such as lactate dehydrogenase A and pyruvate kinase, implicated in the adaptation to increased metabolic demands under myopic stress. Additionally, a decrease in the expression of proteins associated with oxygen transport suggested enhanced vulnerability to oxidative stress. These findings highlight the proactive role of CD29+ Müller cells in modifying the retinal environment in response to myopic stress and provide valuable insights into mechanisms that could help mitigate myopia progression.

Comparison of ocular biometric measurements and intraocular lens power calculation using different methods in eyes with implantable collamer lenses

This prospective cohort study included 80 healthy candidates for Implantable Collamer Lens (ICL) implantation who underwent biometric assessments with Scheimpflug imaging (the Pentacam-AXL) and swept-source optical coherence tomography (SS-OCT; the IOLMaster-700), both before and 3 months after surgery. The main outcome measures were mean keratometry, anterior chamber depth, axial length, and various intraocular lens (IOL) calculation formulas (Haigis, SRK/T, Hoffer Q, Holladay 1, Barrett Universal 2, and Olsen). The interchangeability of the devices was assessed by generating 95% limits of agreement (95% LoA) and associated Bland-Altman plots. The average age of the participants was 31.5 ± 5.4 years (22-43), with 58 (72.5%) being female. Among the cases analyzed, 11 (13.4%) had incorrect anterior lens surface segmentation using the IOLMaster-700, and 1 case (1.2%) had inappropriate segmentation using the Pentacam-AXL. Postoperative IOL power calculation resulted in readings that were, on average, 0.15 to 0.30 D higher compared to preoperative measurements. The 95% LoAs could differ by up to 0.85 D higher after surgery, indicating weak agreement between pre- and postoperative measurements. There was poor agreement between the IOLMaster-700 and Pentacam-AXL in IOL power calculation for eyes with post-ICL implantation, with a difference of more than 1 D in the 95% LoAs. In conclusion, Scheimpflug imaging was found to be less susceptible than the SS-OCT technique to segmentation errors of the anterior lens surface after ICL implantation. Neither device showed interchangeable results for pre- versus postoperative IOL power calculation. The determination of IOL power by the IOLMaster-700 versus Pentacam-AXL was not interchangeable in eyes with ICL implantation.

Dynamic BMP gene expression regulation in chick RPE during recovery from short term optical defocus and form-deprivation

PURPOSE

This study investigated the differential gene expression of BMPs in chick retinal pigment epithelium (RPE) during recovery from short term exposure to optical defocus and form-deprivation (FD) treatments.

METHODS

14-day old White-Leghorn chicks wore either monocular +10 or -10 D lenses, or diffusers for 2 or 48 h, after which eyes were allowed unobstructed vision for up to 96 h. Over this recovery period, refractive errors and choroidal thickness (ChT) were tracked using retinoscopy and high-frequency A-scan ultrasonography. Real-time PCR was used to examine the expression of BMP2, 4, and 7 genes in RPE samples collected 0, 15 min, 2, 24, 48, and 96 h after the termination of treatments. Expression levels in treated eyes and their contralateral control eyes were compared.

RESULTS

After the termination of the lens and diffuser treatments, eyes gradually recovered from induced shifts in refractive error. With all three treatments, ChT changes reached statistical significance after 48 h of treatment, be it thinning with the -10 D lens and diffuser treatments (-0.06 ± 0.03mm, p < 0.05; -0.11 ± 0.04 mm, p < 0.05, resp.), or thickening with the +10 D lens (0.31 ± 0.04 mm, p < 0.001). BMP2 gene expression was rapidly upregulated in eyes wearing the +10 D lens, being statistical significance after 2 h, as well as 48 h of treatment. With the 2 h treatment, the latter gene expression pattern persisted for 15 min into the recovery period, before decreasing to the same level as that of contralateral control eyes, with a short-lived rebound, i.e., upregulation, 24 h into the recovery period. With the longer, 48 h treatment, BMP2 gene expression decreased more gradually, from 739 ± 121% at the end of the treatment period, to 72 ± 14% after 48 h of recovery. Two and 48 h of both -10 D and FD treatments resulted in BMP2 gene expression downregulation, with the time taken for gene expression levels to fully recover varying with the duration of initial treatments. In both cases, BMP2 gene expression downregulation persisted for 15 min into the recovery period, but reversed to upregulation by 2 h. Similar gene expression patterns were also observed for BMP4, although the changes were smaller.

CONCLUSIONS

The observed changes in BMP gene expression in chick RPE imply dynamic, albeit complex regulation, with the duration of exposure and recovery being critical variables for all three types of visual manipulations. This study provides further evidence for a role of the RPE as an important signal relay linking the retina to the choroid and sclera in eye growth regulation.

An integrative predictive model for orthokeratology lens decentration based on diverse metrics

Purpose

To develop a predictive model for orthokeratology (Ortho-K) lens decentration 1 month after wear.

Methods

This study included myopic children who were fitted with Ortho-K lenses at Fujian Provincial Hospital between December 2022 and May 2024. Corneal topography parameters and other relevant metrics were collected pre- and post-treatment. Feature selection was conducted using univariate logistic regression and Lasso regression analysis. A machine learning approach was used to develop multiple predictive models, including Decision Tree, Logistic Regression, Multilayer Perceptron, Random Forest, and Support Vector Machine. Model performance was evaluated using accuracy, sensitivity, specificity, ROC curves, DCA curves, and calibration curves. SHAP values were employed to interpret the models.

Results

The Logistic Regression model demonstrated the best predictive performance, with an AUC of 0.82 (95% CI: 0.69-0.95), accuracy of 77.59%, sensitivity of 85%, and specificity of 61.11%. The most significant predictors identified were age, 8 mm sag height difference, 5 mm Kx1, and 7 mm Kx2. SHAP analysis confirmed the importance of these features, particularly the 8 mm sag height difference.

Conclusions

The Logistic Regression model successfully predicted the risk of Ortho-K lens decentration using key corneal morphological metrics and age. This model provides valuable support for clinicians in optimizing Ortho-K lens fitting strategies, potentially reducing the risk of adverse outcomes and improving the quality of vision for patients. Further validation in clinical settings is recommended.

Control of myopia using diffusion optics spectacle lenses: 4-year results of a multicentre randomised controlled, efficacy and safety study (CYPRESS)

AIMS

To evaluate the myopia control efficacy of Diffusion Optics Technology (DOT) spectacle lenses in children over a 4-year treatment period.

METHODS

CYPRESS Part 1 (NCT03623074) was a 3-year multicentre, randomised, controlled, double-masked trial comparing two investigational spectacle lens DOT designs (Test 1, Test 2) and standard single vision Control lenses in 256 North American children aged 6-10 years. Children completing Part 1 (n=200) were invited to enrol in CYPRESS Part 2 (NCT04947735) for an additional 1-year period. In Part 2, Test 1 (n=35) and Control groups (n=42) continued with their original lens assignment and the Test 2 group (n=21) were crossed over to Test 1 (DOT 0.2) lenses. The co-primary endpoints were change from baseline in axial length (AL) and cycloplegic spherical equivalent refraction (cSER).

RESULTS

Test 1 spectacle lenses demonstrated superiority to the Control in both co-primary endpoints: with a difference between means (Test 1-Control) of -0.13 mm for AL (p=0.018) and 0.33 D for cSER (p=0.008) in Part 1 and -0.05 mm for AL (p=0.038) and 0.13 D for cSER (p=0.043) in Part 2. Comparing treatment effects in Part 1 and 2 suggests that COVID-19 public health restrictions negatively impacted treatment efficacy in study years 2 and 3.

CONCLUSION

DOT 0.2 spectacle lenses are safe and effective at reducing myopia progression, with additional benefit evident in year 4 of wear. These results support the hypothesis that a mild reduction in retinal contrast can slow myopia progression in young children. The unprecedented disruption in participant schooling and lifestyle during the COVID-19 pandemic may have depressed treatment efficacy in Part 1.

Biomechanical changes occur in myopic choroidal stroma and mirror those in the adjacent sclera

Retina-derived growth signals relayed from the choroid to the sclera cause remodeling of the extracellular scleral matrix, resulting in myopic ocular elongation. However, to the best of our knowledge, no studies have assessed changes in choroidal stromal biomechanical properties during myopia progression. Here we utilized 7 µm-resolution scanning acoustic microscopy (SAM) to assess biomechanical properties (bulk modulus (K) and mass density (rho)) of choroidal stroma from guinea pig eyes with form-deprivation (FD) induced myopia. The choroidal stroma had considerable intrinsic strength arising from its biomechanical properties and these were differentially affected by myopia in central and peripheral regions. Choroidal stromal biomechanical values were also highly correlated with those in adjacent scleral regions, and the choroidal stromal-scleral association was stronger in myopic eyes. Biomechanical changes observed in the choroidal stroma of myopic eyes were mirrored to those observed in the adjacent sclera. These findings suggest that choroidal stromal remodeling may accompany myopia and open the door to the source of the signals that cause scleral remodeling in myopia.

Myopia and systemic manifestation of tissue hyperlaxity: A population-based cross-sectional study

BACKGROUND

Whether non-syndromic connective tissue hyperlaxity is associated with myopia is unknown. The aim of this study was to examine the association between systemic signs of tissue hyperlaxity and myopia among adolescents.

METHODS

Included were adolescents assessed before mandatory military service at the age of 16-18 years between 2011 and 2022. Diagnoses of hernias, pes planus, genu varus, genu valgum, and scoliosis, as well as joint injuries were used as surrogate markers for tissue hyperlaxity. The prevalence of these events among adolescents with myopia was evaluated and compared to the non-myopic population.

RESULTS

Included were 920 806 adolescents. The mean age was 17.4 ± 1.4 years and 58.6% were men. Myopia was diagnosed in 290 759 adolescents (31.6%) and high myopia in 24 069 adolescents (2.6%). The prevalence of hernias was higher among adolescents with myopia, (2.76%, 95% confidence interval (95% CI): 2.69%-2.82% vs. 2.60%, 95% CI: 2.57%-2.65%), as were pes planus (14.92%, 95% CI: 14.79-15.05 vs. 13.51%, 95% CI: 13.42-13.59) and scoliosis (9.14%, 95% CI: 9.03-9.24 vs. 7.69%, 95%CI: 7.62-7.76). The prevalence of joint injuries was clinically similar between groups (less than 0.1% difference for ankle, shoulder, and knee injuries), as were genu varum and genu valgum (0.66%, 95%CI: 0.64%-0.69% vs. 0.68%, 95% CI: 0.66-0.70, respectively). Adjusted for possible confounders results remained consistent.

CONCLUSIONS

Among a large sample of Israeli adolescents, those with myopia had a higher prevalence of hernias, pes planus, and scoliosis. These results could suggest a propensity for systemic conditions related to tissue laxity among myopic adolescents.

The protective role of green spaces in mitigating myopia prevalence

Near-sightedness, or myopia, is becoming more prevalent worldwide, but its etiopathogenesis is not fully understood. This review examines the potential protective role of green spaces in reducing myopia prevalence among children and adolescents, based on recent epidemiological studies from various countries. The studies consistently used the Normalized Difference Vegetation Index (NDVI) to quantify green space exposure. The analysis reveals a significant inverse relationship between exposure to green space and the risk of developing myopia, across multiple studies. For example, a 0.1 increase in NDVI within various buffer zones around schools was associated with a 6.3-8.7% reduction in myopia prevalence. Higher residential greenness within a 100-meter buffer around homes was linked to a 38% reduction in the risk of developing myopia among preschool children. The protective effect was observed across different age groups, from preschoolers to high school students. Urban planning factors, such as the size, connectivity, and aggregation of green spaces, also influenced myopia risk. These findings suggest that increasing access to green spaces in urban environments may be an effective strategy for myopia prevention, with important implications for public health and urban planning policies.

Identification of Potential Growth-Related Proteins in Chick Vitreous during Emmetropization Using SWATH-MS and Targeted-Based Proteomics (MRMHR)

The vitreous humor (VH) is a transparent gelatin-like substance that occupies two-thirds of the eyeball and undergoes the most significant changes during eye elongation. Quantitative proteomics on the normal growth period in the VH could provide new insights into understanding its progression mechanism in the early stages of myopia. In this study, a data-independent acquisition (SWATH-MS) was combined with targeted LC-ESI-MS/MS to identify and quantify the relative protein changes in the vitreous during the normal growth period (4, 7, 14, 21 and 28 days old) in the chick model. Chicks were raised under normal growing conditions (12/12 h Dark/light cycle) for 28 days, where ocular measurements, including refractive and biometric measurements, were performed on days 4 (baseline), 7, 14, 21 and 28 (n = 6 chicks at each time point). Extracted vitreous proteins from individual animals were digested and pooled into a left eye pool and a right pool at each time point for protein analysis. The vitreous proteome for chicks was generated using an information-dependent acquisition (IDA) method by combining injections from individual time points. Using individual pool samples, SWATH-MS was employed to quantify proteins between each time point. DEPs were subsequently confirmed in separate batches of animals individually on random eyes (n = 4) using MRMHR between day 7 and day 14. Refraction and vitreous chamber depth (VCD) were found to be significantly changed (p < 0.05, n = 6 at each time point) during the period. A comprehensive vitreous protein ion library was built with 1576 non-redundant proteins (22987 distinct peptides) identified at a 1% false discovery rate (FDR). A total of 12 up-regulated and 26 down-regulated proteins were found across all time points compared to day 7 using SWATH-MS. Several DEPs, such as alpha-fetoprotein, the cadherin family group, neurocan, and reelin, involved in structural and growth-related pathways, were validated for the first time using MRMHR under this experimental condition. This study provided the first comprehensive spectral library of the vitreous for chicks during normal growth as well as a list of potential growth-related protein biomarker candidates using SWATH-MS and MRMHR during the emmetropization period.

Axial length association with corneoscleral sagittal height and scleral asymmetry

PURPOSE

To determine how corneoscleral geometry changes with axial length and to assess the usefulness of including the sagittal configuration of the anterior segment when predicting the axial length.

METHODS

An observational study was performed including 96 healthy subjects (96 eyes). Axial length was calculated from optical biometry (IOL Master 500). Corneal curvature and scleral sagittal height parameters at 13, 14 and 15 mm were obtained automatically using corneoscleral topography (eye surface profiler; ESP). In addition, corneal and scleral sagittal heights at numerous locations (21 radii: 0-10 mm from the corneal apex at 12 angles: 0-330°) were calculated using the raw height data extracted from the ESP. The relationships between axial length and the study parameters were analysed using Pearson correlation analysis. The equations for the prediction of axial length were obtained by fitting multiple linear regression models.

RESULTS

The temporal-nasal scleral asymmetry at 13-, 14- and 15-mm chord lengths was significantly correlated with axial length (r2 ≤ 0.26; p < 0.001). Significant inverse correlations were found between the temporal scleral sagittal height and axial length (r2 ≤ 0.28; p ≤ 0.02). The nasal scleral sagittal height was not associated with axial length. Three significant multiple linear regression models were fitted based on spherical equivalent, corneal radius and scleral asymmetry at 13 (r2 = 0.79; p < 0.001), 14 (r2 = 0.80; p < 0.001) and 15 (r2 = 0.80; p < 0.001) mm chord lengths.

CONCLUSIONS

Larger ocular globes show reduced temporal-nasal scleral asymmetry, mainly due to the lower sagittal height of the temporal sclera. Thus, the geometry of the temporal scleral may be a factor of interest during myopia progression.

Comparison of visual acuity outcome and choroidal thickness variation of intravitreal ranibizumab injection for myopic choroidal neovascularization with or without dome-shaped macula

BACKGROUND

To investigate the visual acuity outcome and choroid thickness (CT) change after intravitreal ranibizumab in highly myopic eyes with or without dome-shaped macula (DSM) in Chinese patients.

METHODS

This retrospective, observative study included 80 treatment-naive eyes (80 patients), which received ranibizumab according to the 1+PRN protocol. The best corrective visual acuity (BCVA) and CT change were compared between eyes with or without DSM.

RESULTS

There was no significant difference between eyes with or without DSM in BCVA and central macular thickness (CMT). The recurrent rate was not different between the two groups during the first year of treatment. The CT was significantly thinner in eyes with DSM than in eyes without DSM before treatment (median 40.00um versus 71.00um), at 1 month after treatment (median 31.00um versus 65.50um), and in the last follow up (median, 32.00um versus 65.00um) (p = 0.0101). Axial length (AL) was longer in eyes with DSM than those without DSM (median, 29.17 mm versus 28.10 mm) before treatment, and in the last follow up (median, 29.44 mm versus 28.20 mm) (p = 0.0055). The CT was significantly correlated with AL (p < 0.0001).

CONCLUSIONS

No difference was found in visual outcome between eyes with or without DSM. The visual acuity significantly improved at 1 month after ranibizumab injection and it was recovery sooner in extrafoveal choroidal neovascularization (CNV) group than in subfoveal CNV group. The CT was thinner in eyes with DSM, which was significantly correlated with AL.

Myopic shift in female mice after ovariectomy

Myopia is a global public health concern, with a higher prevalence in women than that in male. As the relationship between sex hormone and myopia remains unclear, we aimed to reveal the relationship between sex hormone and myopia by removing the ovaries of mice and measuring changes in ocular parameters related to myopia. Lens-induced myopia (LIM) surgeries were performed on 3-week-old male mice and age-matched female mice to evaluate the effects of sex on myopia development, which indicated a high degree of myopia and rapid progression of axial elongation in male mice. Bilateral ovariectomy (OVX) performed on 4-week-old female mice induced myopic refraction status in ovariectomized mice. Although axial length elongation was larger in ovariectomized mice than that in sham control mice, the result was insignificant. To further reveal the relationship between female sex hormones and myopia, LIM combined with OVX was performed, which revealed a magnified myopic refraction status in ovariectomized mice. Nevertheless, elongation of the anterior chamber depth in the - 30 D lens-treated eyes significantly increased in LIM + OVX mice compared with the frame-treated eyes in LIM + OVX mice and - 30 D lens-treated eyes in LIM + Sham surgery mice. Sex hormones play a role in regulating myopia development in female mice.

Soft peripheral contact lens for eye elongation control (SPACE): 1-year results of a double-blinded randomized controlled trial

PURPOSE

To examine the safety and efficacy of soft multifocal contact lenses on slowing the rate of myopia progression.

METHODS

A prospective, randomized, double-masked clinical trial was conducted including 115 children (55 boys and 60 girls) aged 8 to 15 years. Children were assigned to wear one of two daily disposable soft contact lens designs; a multifocal design (Pegavision) or a dual-focus design (MiSight, Coopervision) in both eyes for at least 8 h per day for one year. All contact lenses were replaced on a daily basis. Measurements were obtained using a logMAR vision meter, including objective refraction, handheld retinoscopy, high (96 %) and low (12 %) contrast sensitivity, and distance and near visual acuity. Axial length was measured every 6 months.

RESULTS

After one year, the spherical equivalent refractive error and axial length of the experimental group (Pegavision) increased by -0.50 ± 0.48 D and 0.24 ± 0.16 mm, respectively, in the right eye and -0.47 ± 0.37 D and 0.23 ± 0.16 mm, respectively, in the left eye. The spherical equivalent refractive error and axial length of the control group (MiSight) increased by -0.48 ± 0.47 D and 0.22 ± 0.13 mm, respectively, in the right eye and by -0.50 ± 0.44 D and 0.23 ± 0.14 mm, respectively, in the left eye, with no significant differences observed between the two lens types.

CONCLUSIONS

The one-year results from this clinical trial show that the multifocal soft contact lenses used in the experimental group have a similar myopia control efficacy with respect to spherical equivalent refraction and axial length elongation as a commercially available dual focus soft contact lens design.

The lack of causal link between myopia and intraocular pressure: Insights from cross-sectional analysis and Mendelian randomization study

OBJECTIVE

This study aimed to explore the potential causal relationship between intraocular pressure (IOP) and myopia.

METHODS

The study included 3,459 patients who underwent corneal refractive surgery at our institution between 2021 and 2023. Preoperative data on IOP, spherical equivalent (SE), axial length (AL), and corneal thickness (CCT) were collected. The association between IOP and myopia was investigated through rank correlation analysis, and causal inference was examined using Mendelian randomization (MR) methods, including MR-Egger, weighted median, mode-based estimation, simple mode, and inverse variance weighted (IVW) approaches. Utilizing summary statistics from genome-wide association studies (GWAS), IOP was considered as the exposure, with myopia as the outcome variable. IVW method was employed for the primary analysis, supplemented by sensitivity analyses.

RESULTS

Cross-sectional analysis revealed a non-significant association between corrected IOP (cIOP) and myopia (r = -0.019, P = 0.12). MR analysis indicated a non-significant genetic causal relationship between cIOP and myopia under the IVW method (OR = 1.001; 95 % CI [0.999-1.003], P = 0.22), a finding corroborated in replication samples (OR = 0.98; 95 % CI [0.96-1.00], P = 0.099).

CONCLUSION

This study did not find a direct causal link between IOP and the development of myopia. These findings challenge the traditional role attributed to IOP in the progression of myopia and highlight the complex, multifactorial process of myopia development. This provides a new perspective on understanding the intricate mechanisms behind myopia progression.

Absorption and attachment of atropine to etafilcon A contact lenses

PURPOSE

Myopia (short-sightedness) is a growing vision problem worldwide. Currently atropine eye drops are used to control the progression of myopia but these suffer from potential lack of bioavailability and low ocular residence time. Commercially available myopia control contact lenses are also used to limit myopia progression, but neither atropine nor contact lenses individually completely stop progression. Development of myopia control contact lenses which could deliver therapeutic doses of atropine is thus desirable and may provide increased efficacy. This study was designed to explore the feasibility of attaching atropine to etafilcon A contact lenses through an esterification reaction.

METHODS

Carboxylic acid groups on etafilcon A contact lenses were quantified using Toluidine Blue O. The carboxylic acid groups in etafilcon A contact lenses were activated using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC-HCl) and N-hydroxysuccinimide (NHS) crosslinkers after which atropine was added to undergo potential binding via esterification. Atropine was released from lenses by alkaline hydrolysis. Reverse phase high performance liquid chromatography (HPLC) was used to detect and quantify the released atropine and its degradation products in solution. Contact lenses that had not been activated by EDC-NHS (controls) were also examined to determine the amount of atropine that could be absorbed rather than chemically bound to lenses.

RESULTS

Each etafilcon A contact lens contained 741.1 ± 5.5 µg carboxylic acid groups which may be available for esterification. HPLC had a limit of detection for atropine of 0.38 µg/mL and for tropic acid, an atropine degradation product, of 0.80 µg/mL. The limits of quantification were 1.16 µg/mL for atropine and 2.41 µg/mL for tropic acid in NH4HCO3. The etafilcon A lenses adsorbed up to 7.69 μg atropine when incubated in a 5 mg/mL atropine solution for 24 h. However, there was no evidence that atropine could be chemically linked to the lenses, as washing in a high concentration of NaCl removed all the atropine from the contact lenses with no atropine being subsequently released from the lenses after incubating in 0.01 N NH4HCO3.

CONCLUSIONS

Etafilcon A contact lenses contain free carboxylic acids which may be an appropriate option for attaching drugs such as atropine. Etafilcon A lenses adsorbed up to 7.69 μg atropine, which would be more than enough to deliver atropine to eyes to control myopia. However, atropine could not be chemically bound to the carboxylic acids of the etafilcon A lenses using this methodology.

A new look at the myopia control efficacy of orthokeratology

PURPOSE

To evaluate the efficacy of orthokeratology contact lens wear in slowing the axial elongation of the eye in myopic children.

METHODS

Data from three prospective studies, which evaluated the use of orthokeratology for slowing myopia progression in children in comparison to a parallel control group of distance, single-vision spectacle lens wearers over a 2-year period, were pooled together for analysis.

RESULTS

Collectively, data from 125 orthokeratology and 118 control subjects were analyzed in this study. Of these, 101 (81 %) and 88 (75 %) orthokeratology and control subjects completed the 2-year follow-up period, respectively. Statistically significant differences in the change in axial length from baseline were found over time, between groups and for the time*group interaction (all p < 0.001), indicating that the rate of increase in axial length over time was significantly lower in the orthokeratology versus the control group. The lower axial elongation of the orthokeratology versus the control group was statistically significant at all time points (all p < 0.001), with significant differences being also present between each of the different pairs of time points (all p < 0.001). The interactions of group with age, gender, mean spherical refractive error and ethnicity at baseline were not significant (p > 0.05). The change in axial length at the 2-year visit in comparison to baseline for the orthokeratology and control groups were 0.41 ± 0.25 and 0.65 ± 0.30 mm, respectively, thus providing a treatment effect following 2-years of lens wear of 0.24 mm (95 % confidence intervals: 0.15 to 0.34 mm). About 40 % and 25 % of the orthokeratology subjects experienced remarkably low and high levels of myopia progression, respectively (2-years axial elongation: ≤0.30 mm and >0.59 mm, respectively).

CONCLUSIONS

Orthokeratology lens wear slows the axial elongation of the eye in comparison to spectacle lens wear in myopic children. The use of these lenses for slowing myopia progression appears to be very effective and not effective at all in 40% and 25% of orthokeratology lens wearers, respectively.

Epidemiology of Myopia: Prevalence, Risk Factors and Effects of Myopia

Myopia is the most common cause of visual impairment in children and young adults. In order to assess the consequences for society, it is necessary to know temporal trends in prevalence, incidence and associated factors in childhood and adolescence, as well as the rate of myopia progression, as based on epidemiological research. This paper presents a literature review of publications from 2020 up to March 2024, supplemented by other relevant publications. The prevalence of myopia in children and adolescents in Germany is almost stable and is significantly lower than in Asia. The development of myopia is influenced by outdoor activity, parental myopia, genetics and near work, while insufficient time spent outdoors in childhood is a significant and controllable risk factor for myopia-related complications such as myopic maculopathy, glaucoma, and retinal detachment.

Is the Change in Prevalence of High Myopia Compared to That of Myopia Really Disproportionate?

Purpose

It has been noted that, at higher prevalences, the rate of change in the prevalence of high myopia seems to be disproportionately greater compared with the rate of change in the prevalence of myopia. A simple, evidence-based explanation for this relationship is offered.

Methods

Using a convenience sample of 41 datasets with prevalence estimates for at least two refractive error thresholds (e.g., -0.50 and -6.00 D) the common slope of the logit vs. refractive threshold was applied to model expected rates of high myopia across the myopia prevalence range and the corresponding ratio of change in high myopia to myopia prevalence.

Results

The logit of high myopia is related linearly to the logit of myopia. The ratio of increase in high myopia prevalence to that for myopia prevalence increases with underlying prevalence. For example, an increase in myopia prevalence from 19% to 20% is modelled to be accompanied by a 0.1% increase in the prevalence of high myopia from 1.55% to 1.65%-a ratio of 0.1. Conversely, an increase in myopia prevalence from 79% to 80% is predicted to result in a 1% increase in the prevalence of high myopia from 20.6% to 21.6%-a ratio of 1.0.

Conclusions

The increase in the prevalence of high myopia compared with that of myopia as the latter increases is merely a function of the underlying nature of refractive error probability distributions and requires no further investigation as to its origin.

Translational Relevance

This study shows how the prevalence of myopia and high myopia are inter-related. A widespread effort to slow myopia progression will affect the prevalence of high myopia but not myopia in general. In contrast, efforts to delay myopia onset will affect both.

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.