A systematic review of near work and myopia: measurement, relationships, mechanisms and clinical corollaries

Evaluation of the perception of information from ChatGPT in myopia education: Perspectives of students and professionals

PURPOSE

The purpose of this study was to compare the perception and understanding of the information provided by ChatGPT regarding myopia among optometry students, optometrists undertaking a Master degree and practicing optometrists.

METHODS

This was a cross-sectional descriptive study using a structured questionnaire distributed via Wooclap to 225 participants (125 optometry students, 21 Masters student and 79 practicing optometrists). All participants evaluated the responses generated by ChatGPT Version 4.0 using a five-point scale: very poor, poor, acceptable, good and very good. Data were analysed using SPSS, applying descriptive analysis and chi-squared tests to assess the significance of differences observed between the groups.

RESULTS

Practicing optometrists, with an average age of 39.7 ± 11.0 and 15.2 ± 7.5 years of professional experience, rated the information provided by ChatGPT on myopia complications more positively than the optometry and Masters student, highlighting the importance of clinical experience (p < 0.001). Alternatively, this may indicate a difference in awareness, knowledge and training, with younger students potentially being more speculative in their evaluations. The perceptions about myopia prevention among the groups were similar (p = 0.28). At the same time, the perceptions of the effectiveness of treatments such as contact lenses and pharmaceutical agents showed differences, with optometrists rating these treatments more positively (p < 0.001 and p = 0.004, respectively).

CONCLUSIONS

This study showed differences in the perception and interpretation of the information provided by ChatGPT about myopia depending on the level of education. While AI plays an important role in education, practicing optometrists trust the information extracted by ChatGPT more than optometry students.

Validation of real-time viewing distance and ambient illumination measurement with two wearable sensors

PURPOSE

To report the repeatability and accuracy of viewing distance and ambient illumination measured with the Vivior and Clouclip wearable sensors in a controlled laboratory setting and while young adults performed different near visual tasks.

METHODS

For Study 1, viewing distance and ambient illumination were measured repeatedly for 2 days with two sensors mounted on a mannequin. Results were compared with standard measures (ruler, lux meter) using linear regression and Bland-Altman analysis. In Study 2, viewing distances were captured in 13 young adults while they performed four near tasks for 20 min each (reading a printed article, reading an article on an iPad, typing on a laptop or watching videos on an iPad) under three illuminations (500, 250 and 25 lux). Results were compared between the devices and with a standard ruler and differences tested statistically using ANOVA and Tukey's multiple comparison tests.

RESULTS

In Study 1, a positive linear relationship was observed between viewing distances measured by each sensor and the standard ruler (mean [SD] difference of -0.12 cm [0.23] for Vivior, -0.18 cm [0.51] for Clouclip), with good repeatability (mean [SD] difference between 2 days was 0.02 cm [0.24] for Vivior, -0.14 cm [0.35] for Clouclip). A positive linear relationship was also observed between illumination measured by each sensor and the luxmeter (mean [SD] difference of -16.85 lux [325.5] for Vivior, 39.12 lux [335.6] for Clouclip). In Study 2, the viewing distances during the four near tasks were not significantly different between the three methods used. Shorter working distances were measured with all methods when reading a printed article compared to typing on a laptop and watching a video on the iPad (all p < 0.05).

CONCLUSION

Vivior and Clouclip are recommended for real-time capture of near vision duration, distance and light exposure in future studies aiming to understand the effect of habitual visual environment.

The causal effect of multiple lifestyles and myopia: a Mendelian randomization study

Previous studies have demonstrated that lifestyle was associated with myopia. This study used Mendelian randomization (MR) analysis to examine the causal relationships between the time of computer use, the time outdoors in summer and the time outdoors in winter and myopia. Subsequently, univariate MR (UVMR) analyses were carried out respectively on the three exposure factors and myopia, and the results were mainly based on the inverse-variance-weighted method. In addition, sensitivity analyses were also conducted, including heterogeneity tests, horizontal pleiotropy and leave-one-out methods, to evaluate the stability of the MR results. Multivariate MR (MVMR) analysis was also carried out. The UVMR analysis showed that two of the exposure factors had causal relationships with myopia: the time of computer use was a risk factor, and the time spent outdoors in summer was a protective factor. However, the time spent outdoors in winter had no direct impact on myopia. Furthermore, further mediation analysis showed that the frequency of solarium/sunlamp use was a mediating factor between the time outdoors in winter-myopia, and the mediating effect accounted for 36.93%. In conclusion, when multiple factors occurred simultaneously, the time of computer use in summer and the time of outdoor activities had a potential impact on myopia, and the time outdoors in winter affected myopia through the frequency of solarium/sunlamp use.

The influence of orthokeratology on peripheral refraction during accommodation

SIGNIFICANCE

The change in peripheral refraction from hyperopic to myopic defocus following orthokeratology (OK) has been recognized as a main factor in myopia control. However, the impact of OK lenses on peripheral refraction at nearpoints in myopic eyes still requires further investigation.

PURPOSE

This study aims to investigate changes in peripheral refraction during accommodation in myopic adults after orthokeratology (OK) wear.

METHODS

Twenty-four selected myopic adults (mean spherical equivalent: -2.70 ± 1.04 D) participated in this study. Peripheral refractions were measured by an auto-refractor with targets located at 25 cm and 50 cm from the eye. Measurements were performed across ± 30º of the horizontal field in 5º steps from the visual axis of subject's right eye before and after wearing the OK lens. The statistical package SPSS was used to analyze the data to determine the relationship between peripheral refractions and accommodation.

RESULTS

After wearing the OK lens, the peripheral refraction became more myopic with increasing eccentricity during accommodation (t > 2.80, p < 0.01, N30º, N25º, N20º, T15º, T20º, T25º and T30º, for 25 cm and 50 cm). While relative hyperopic reflective errors were observed in the central (accommodative lag) and near peripheral (= < 15 º) retinal fields (t < -2.5, p < 0.02, for 0º, N5º, N10º, N15º and T10º for 25 cm and 50 cm), relative myopic refractive errors were evident in the farther periphery (> 15 º). (for 25 cm, -0.45 ± 1.18, -0.71 ± 1.47, -1.00 ± 1.31 and -1.70 ± 2.16D, for N30º, T20º, T25º, and T30º; for 50 cm, -0.76 ± 1.28, -0.84 ± 1.05; -1.17 ± 1.30 and -2.15 ± 1.81D, for N30º, T20º, T25º, and T30º; t > 2.5, P < 0.02).

CONCLUSION

The myopic shift of peripheral refraction from the OK lens was partly counteracted by an insufficient change in refractive power of the eye during accommodation. Even though the refractive errors become relative hyperopic in the central and near peripheral retinal fields, relative myopic refraction was still maintained in the farther periphery for the accommodated myopic eyes treated with OK lenses.

Wavefront sensing: A breakthrough for objective evaluation of dynamic accommodation in accommodative dysfunctions

The purpose of this study was to use wavefront sensing as an objective method to detect and assess dynamic accommodation in subjects with accommodative dysfunctions and symptoms related to near-vision tasks. Sixty-three subjects were divided into control (N = 18), symptomatic without any accommodative dysfunction (SWD) (N = 18), infacility of accommodation (INFA) (N = 6), excess of accommodation (EA) (N = 9), and insufficiency of accommodation (INSA) (N = 12) groups. Accommodation was stimulated in different cycles of accommodation and disaccommodation while ocular aberrations were measured. Dynamic accommodation was computed from ocular wavefront aberrations and then analysed, including response time, peak velocity, and microfluctuations. Subjects with accommodative dysfunctions showed alterations in accommodative responses compared to the control group, characterized by slower and excessive/reduced responses, as well as an increase in accommodative microfluctuations and difficulty in relaxing accommodation to different accommodative demands. The SWD group showed significant changes compared to the control group, suggesting accommodative problems not previously detected in clinical examinations and explaining the symptoms reported by these subjects. The specific patterns of the characteristics of dynamic accommodation are presented for the different accommodative dysfunctions. The objective assessment of dynamic accommodation using wavefront sensing, analysed for different accommodative demands, provides a comprehensive approach to the detection and characterisation of accommodative dysfunctions. This method enables the improvement of the precision of the diagnosis of accommodative dysfunctions and allows its detection in cases that may not be detected by current clinical examinations. In addition, this method may contribute to personalized treatment planning, potentially improving patient outcomes in clinical practice.

Exploring Molecular Pathways in Refractive Errors Associated with Inherited Retinal Dystrophies

The term inherited retinal dystrophies (IRDs) refers to a diverse range of conditions characterized by retinal dysfunction, and mostly deterioration, leading to a gradual decay of the visual function and eventually to total vision loss. IRDs have a global impact on about 1 in every 3000 to 4000 individuals. However, the prevalence statistics might differ significantly depending on the exact type of dystrophy and the demographic being examined. The cellular pathophysiology and genetic foundation of IRDs have been extensively studied, however, knowledge regarding associated refractive errors remain limited. This review aims to clarify the cellular and molecular processes that underlie refractive errors in IRDs. We did a thorough search of the current literature (Pubmed, accession Feb 2024), selecting works describing phenotypic differences among genes-related to IRDs, particularly in relation to refractive errors. First, we summarize the wide range of IRDs and their genetic causes, describing the genes and biological pathways connected to the etiology of the disease. We then explore the complex relationship between refractive errors and retinal dysfunction, including how the impairment of the vision-related mechanisms in the retina can affect ocular biometry and optical characteristics. New data about the involvement of aberrant signaling pathways, photoreceptor degeneration, and dysfunctional retinal pigment epithelium (RPE) in the development of refractive errors in IRDs have been examined. We also discuss the therapeutic implications of refractive defects in individuals with IRD, including possible approaches to treating visual impairments. In addition, we address the value of using cutting-edge imaging methods and animal models to examine refractive errors linked to IRDs and suggest future lines of inquiry for identifying new targets for treatment. In summary, this study presents an integrated understanding of the cellular and molecular mechanisms underlying refractive errors in IRDs. It illuminates the intricacies of ocular phenotypes in these conditions and offers a tool for understanding mechanisms underlying isolated refractive errors, besides the IRD-related forms.

Retinal Responses to Short- and Longer-Term Predominant ON or OFF Stimulation in Emmetropes and Myopes

Purpose

The link between nearwork and myopia is controversially discussed. Features of the viewing target may stimulate eye growth, for example, black-on-white text was found to stimulate retinal OFF pathways and promote choroidal thinning, whereas inverted text led to ON pathway stimulation and thicker choroids. We used electroretinograms (ERGs) to compare retinal activity for both stimuli in the parafovea in emmetropes and myopes and studied the effects of adaptation.

Methods

ERGs were recorded in 42 subjects (18-30 years) during 200 ms-flashes on a CRT monitor, superimposed with an annulus or circles filled with gray or inverted or standard text. Ganzfeld ERGs (500 ms) were taken before and after 30 minutes of reading standard or inverted text at 25 cm to determine adaptation effects. The ON- (b-wave) and OFF-responses (d-wave) were analyzed using linear mixed effects models and pointwise t-testing.

Results

(1) Stimulus size affected retinal ON-responses of both groups (p < 0.001), with larger responses to a 6 to 12 degrees annulus than to a 12-degree circle. (2) Myopes displayed larger ON-responses to inverted text contrast than emmetropes within 6 to 12 degrees. (3) After adaptation to text, ON-responses were reduced (p = 0.010) irrespective of refraction and contrast. (4) Emmetropes showed reduced ON- and OFF-responses to inverted text contrast. (5) Only emmetropes had reduced ON- and larger OFF-responses after adapting to standard text.

Conclusions

Myopes had largest ON-responses with inverted contrast in the perifovea. Emmetropes displayed larger adaptive changes after ON/OFF stimulation. In both groups, inverted contrast still reduced ON-responses, suggesting that efficient activation of retinal ON channels to inhibit myopia might require additional OFF channel suppression.

Measuring the visual environment of children and young people at risk of myopia: a scoping review

PURPOSE

Myopia (short-sightedness) is an emerging WHO priority eye disease. Rise in prevalence and severity are driven by changes in lifestyle and environment of children and young people (CYP), including less time spent in bright daylight and more time spent on near-vision activities. We aimed to systematically map the literature describing direct, objective measurements of the visual environment of CYP.

METHODS

We conducted searches in Ovid Medline 1946, Ovid Embase and The Cochrane Central Register of Controlled Trials in November 2024. We included primary research written in English on environmental/behavioural factors and myopia onset/progression in CYP 3-18 years. Two reviewers independently screened titles/abstracts/full texts.

RESULTS

We included 34 articles: 21 explored the association of indoor and/or outdoor light exposure and myopia and included light measurements, two near-vision activities, four both light and near-work, four time outdoors without illuminance measurements, and three light exposure based on meteorological data. Most measurements were carried out at the level of individual children, rather than the surrounding environment alone.

CONCLUSION

Despite limitations in measurement techniques, there is evidence that reduced illuminance, less time spent in bright light and increased daily duration/sustained episodes of near-vision activities and reduced working distance are associated with increased myopia prevalence/progression.

Horizontal Gaze Tolerance and Its Effects on Visual Sensitivity in Glaucoma

Purpose

This study evaluates the effect of 6° horizontal gaze tolerance on visual field mean sensitivity (MS) in patients with glaucoma using a binocular head-mounted automated perimeter, following findings of structural changes in the posterior globe from magnetic resonance imaging and optical coherence tomography.

Methods

In this cross-sectional study, a total of 161 eyes (85 primary open-angle glaucoma [POAG] and 76 healthy) from 117 participants were included. Logistic regression and 1:1 matched analysis assessed the propensity score for glaucoma and healthy eyes, considering age, sex, and axial length as confounders. Visual field tests were performed with the imo perimeter (CREWT Medical Systems, Inc., Tokyo, Japan) at central gaze, 6° abduction, and 6° adduction positions as fixation points. A mixed-effects model was used to compare MS under all conditions.

Results

The analysis included a total of 82 eyes, with 41 POAG and 41 healthy after matching. The mean (standard deviation) age was 68.0 (11.0) years, with a mean deviation of -9.9 (6.6) dB for POAG and -1.0 (1.9) dB for healthy eyes using Humphrey field analysis 24-2. MS did not significantly differ among central gaze (27.0 [1.8] dB), abduction (27.1 [1.9] dB), and adduction (26.9 [2.2] dB) in healthy eyes (P = 0.650). However, MS was significantly lower for adduction (17.2 [5.9] dB) compared to central gaze (18.1 [5.9] dB) and abduction (17.9 [5.9] dB) in glaucoma eyes (P = 0.001 and P = 0.022, respectively).

Conclusions

Horizontal gaze, especially in adduction, significantly reduces visual sensitivity in glaucoma, suggesting a specific vulnerability associated with eye movement. This finding highlights the importance of eye positioning in glaucoma, warranting further investigation of its clinical significance.

Refractive development II: Modelling normal and myopic eye growth

PURPOSE

During refractive development, eye growth is controlled by a combination of genetically pre-programmed processes and retinal feedback to minimise the refractive error. This work presents a basic differential model of how this process may take place.

METHODS

The description starts from two bi-exponential descriptions of the axial power Pax (or dioptric distance) and total refractive power Peye, the difference between which corresponds with the spherical refractive error S. This description is rewritten as an ordinary differential equation and supplemented by a retinal feedback function that combines retinal blur (closed loop) with a term describing excessive axial growth (open loop). This model is controlled by a total of 18 parameters that allow for a wide variety of developmental behaviours.

RESULTS

The proposed model reproduces refractive development growth curves found in the literature for both healthy and myopic eyes. An early onset of myopisation, a large growth term and a high minimum for the crystalline lens power all lead to higher degrees of myopia. Assigning more importance to the feedback than to the pre-programmed growth makes the model more sensitive to myopogenic influences. Applying refractive corrections to the model, undercorrection is found to produce more myopia. The model compensates for a low-powered imposed lens and can return to (near) emmetropia if that imposed lens is removed quickly thereafter. Finally, simulating the effect of a diffuser leads to high myopia.

CONCLUSION

Using a series of basic assumptions, the proposed model recreates many well-known experimental and clinical results about refractive development from the literature while placing them in a standardised context. This contributes to a broader understanding of the origins of refractive errors, and future versions may help in the development of solutions for myopia control.

Slowing of Greater Axial Length Elongation Stemming from the Coronavirus Disease 2019 Pandemic with Increasing Time Outdoors: The Tokyo Myopia Study

Purpose

To investigate the changes in axial length (AL) elongation and other ocular parameters before and during the coronavirus disease 2019 pandemic.

Design

A longitudinal school-based study.

Participants

Public elementary schoolchildren in Tokyo (grades 1-6; age, 6-12 years) participated in this study from 2018 to 2021.

Methods

All participants underwent eye examinations and provided written consent to measurements of the noncycloplegic refraction and ocular biometry including AL, among others. The students' parents also completed a questionnaire about the students' lifestyles. We included the right eye in our analysis and compared the changes in the ocular parameters among the periods using a linear mixed-effects model for repeated measures and examined the univariate and step-wise multiple regression analyses to evaluate the associations between myopia and other covariates.

Main Outcome Measures

Changes in AL elongation and other ocular parameters from 2018 to 2019 (prepandemic), that of 2019 to 2020 (immediately after the pandemic onset), and that of 2020 to 2021 (during the pandemic).

Results

A total of 578 students before the pandemic period, 432 immediately after the pandemic onset, and 457 during the pandemic period were evaluated. The changes in the ALs and spherical equivalents (SEs) a year before, immediately after onset, and during the pandemic were 0.31 mm/-0.20 diopter, 0.38 mm/-0.27 diopter, and 0.28 mm/-0.47 diopter, respectively (ALs, P < 0.001; SEs, P = 0.014). The results of the questionnaire showed that time spent outdoors daily had changed during the 3 years to 79, 63, and 77 minutes/day, respectively (P < 0.001). Time spent using smartphones or tablets increased year by year to 41, 52, and 62 minutes/day (P < 0.001). The greatest AL elongation occurred during the period when the shortest amount of time was spent outdoors during the 3 years.

Conclusions

These results suggested that the school closures and decreasing time spent outdoors might have caused greater AL elongation among schoolchildren in Tokyo; however, it is possible that, although the time spent in near work still increased, the return to the time spent outdoors to the prepandemic levels may have affected the slowing of AL elongation after lockdown.

Financial Disclosures

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

Sunlight: Time for a Rethink?

UVR is a skin carcinogen, yet no studies link sun exposure to increased all-cause mortality. Epidemiological studies from the United Kingdom and Sweden link sun exposure with reduced all-cause, cardiovascular, and cancer mortality. Vitamin D synthesis is dependent on UVB exposure. Individuals with higher serum levels of vitamin D are healthier in many ways, yet multiple trials of oral vitamin D supplementation show little benefit. Growing evidence shows that sunlight has health benefits through vitamin D-independent pathways, such as photomobilization of nitric oxide from cutaneous stores with reduction in cardiovascular morbidity. Sunlight has important systemic health benefit as well as risks.

Ocular morbidity profiles of out-of-school children in a North Indian urban slum

PURPOSE

This study evaluates the recent trends in ocular morbidities and vision-related practices in "out-of-school" children in urban slums of Gurugram in North India.

METHODS

In this observational study, a validated questionnaire was administered to 161 students from two nonformal slum schools. Sociocultural, demographic data, vision-related practices, and visual acuity with subjective refraction of the children were recorded.

RESULTS

A total of 80 boys and 81 girls (9.17 ± 2.58 years) participated in this study. About 40% of the children were from lower socioeconomic status. The visual acuity recorded for all the children, except three children, was 6/6 in both eyes. One child had a pre-phthisical eye with no light perception, following a childhood trauma, with the other eye having 6/6 vision. Two children had refractive errors (myopia and compound myopic astigmatism), with a best corrected visual acuity (BCVA) of 6/6. Thirteen children (8%) had Bitot's spots and 67 (35.4%) had allergic conjunctivitis. Eight (5%) children complained of dry eye-related symptoms like redness and watering of eyes, while 19 (11.8%) had diffuse headache. Average number of years spent in school for these children was less than 1.7 years (range: 1 month-6 years). Only 10.5% of the children gave the history of watching television more than 30 h/week. Significant association was found between the income of father and use of digital devices in children below 10 years ( P = 0.003) and children playing outdoors ( P = 0.001). There was a significant association noted for age and use of digital devices ( P = 0.037).

CONCLUSION

The prevalence of refractive errors in "out-of-school" children of urban slum was much less than the national average. Almost one in three children suffered from eye allergies, while 8% children had Bitot's spots. The data about the prevalence of ocular comorbidities in underserved areas like urban slums can be used to update and strategize eye health-care delivery models for out-of-school children.

Mechanisms of emmetropization and what might go wrong in myopia

Studies in animal models and humans have shown that refractive state is optimized during postnatal development by a closed-loop negative feedback system that uses retinal image defocus as an error signal, a mechanism called emmetropization. The sensor to detect defocus and its sign resides in the retina itself. The retina and/or the retinal pigment epithelium (RPE) presumably releases biochemical messengers to change choroidal thickness and modulate the growth rates of the underlying sclera. A central question arises: if emmetropization operates as a closed-loop system, why does it not stop myopia development? Recent experiments in young human subjects have shown that (1) the emmetropic retina can perfectly distinguish between real positive defocus and simulated defocus, and trigger transient axial eye shortening or elongation, respectively. (2) Strikingly, the myopic retina has reduced ability to inhibit eye growth when positive defocus is imposed. (3) The bi-directional response of the emmetropic retina is elicited with low spatial frequency information below 8 cyc/deg, which makes it unlikely that optical higher-order aberrations play a role. (4) The retinal mechanism for the detection of the sign of defocus involves a comparison of defocus blur in the blue (S-cone) and red end of the spectrum (L + M-cones) but, again, the myopic retina is not responsive, at least not in short-term experiments. This suggests that it cannot fully trigger the inhibitory arm of the emmetropization feedback loop. As a result, with an open feedback loop, myopia development becomes "open-loop".

Development of the University of Houston near work, environment, activity, and refraction (UH NEAR) survey for myopia

CLINICAL RELEVANCE

There is a need to better elucidate demographic and behavioural factors that are contributing to the rising prevalence of myopia. Doing so will aid in developing evidence-based recommendations for behavioural modifications to prevent onset and slow progression of myopia in children.

BACKGROUND

The contributions of environmental and behavioural factors in myopia remain unclear. The goal of this work was to provide a standardised survey to better understand risk factors for myopia.

METHODS

Development of the survey was carried out in 4 phases. In phase 1, three methods (direct, lay terms, and indirect) of parental reporting for the presence of myopia in their child were investigated through a questionnaire (N = 109) to determine sensitivity and specificity. The best method determined from phase 1 was used in phase 2, where questions regarding demographics, ocular history, and visual behaviour were compiled and refined. In phase 3, the survey was administered to focus groups of parents (N = 9). In phase 4, a scoring system was developed.

RESULTS

The highest sensitivity for parental reporting for myopia of their child was the indirect method (0.84), and the lowest sensitivity was the direct method (0.41). The highest specificity was the direct method (0.86), once excluding the 'do not know' responses, and the lowest specificity was the indirect method (0.53). The direct method yielded a 53.2% 'do not know' response rate, 50.5% for the lay method, and 1.8% for the indirect method. Time to complete the survey was 10:09 ± 2:45 minutes.

CONCLUSION

This study provides a comprehensive and up-to-date myopia risk factor survey that can be utilised by researchers and clinicians. Parents found the survey to be easy to understand and relatively quick to answer, and the scoring system allows quantification of behaviours across different categories using provided equations.

Myopia Prevalence in Latin American Children and Adolescents: A Systematic Review and Meta-Analysis

Although myopia is a growing global concern, comprehensive studies on its prevalence among Latin American (LATAM) children and adolescents are still lacking. Thus, we conducted a systematic review and meta-analysis to determine the prevalence of myopia in LATAM children and adolescents aged three to 20. The study conducted a thorough literature search from January 1, 1975, to February 28, 2023, identifying 24 studies on the prevalence of myopia in LATAM that met the inclusion criteria. Quality assessment and standardized data collection were performed. The meta-analysis used a random-effects model due to heterogeneity and calculated prevalence rates. Finally, the analysis of data from 24 eligible studies revealed a myopia prevalence of 8.61% (range 0.80-47.36%, 95% confidence interval (CI): 5.22-13.87%, p < 0.05) among 165,721 LATAM children and adolescents. No significant age-based associations or temporal trends were observed in this study. Studies with non-cycloplegic or objective assessment exhibited a numerically higher, although statistically non-significant, myopia prevalence (10.62%, 95% CI: 4.9-21.6%) compared to studies using cycloplegia (7.17%, 95% CI: 3.40-14.50%). In conclusion, myopia affects approximately one in 11 LATAM children and adolescents. Given the increasing exposure of LATAM youth to known myopia risk factors, such as extensive near-work, online learning, and limited outdoor activities, it is crucial to monitor myopia trends in this region. Further research is imperative to address and prevent myopia in LATAM.

Myopia Control: Are We Ready for an Evidence Based Approach?

INTRODUCTION

Myopia and its vision-threatening complications present a significant public health problem. This review aims to provide an updated overview of the multitude of known and emerging interventions to control myopia, including their potential effect, safety, and costs.

METHODS

A systematic literature search of three databases was conducted. Interventions were grouped into four categories: environmental/behavioral (outdoor time, near work), pharmacological (e.g., atropine), optical interventions (spectacles and contact lenses), and novel approaches such as red-light (RLRL) therapies. Review articles and original articles on randomized controlled trials (RCT) were selected.

RESULTS

From the initial 3224 retrieved records, 18 reviews and 41 original articles reporting results from RCTs were included. While there is more evidence supporting the efficacy of low-dose atropine and certain myopia-controlling contact lenses in slowing myopia progression, the evidence about the efficacy of the newer interventions, such as spectacle lenses (e.g., defocus incorporated multiple segments and highly aspheric lenslets) is more limited. Behavioral interventions, i.e., increased outdoor time, seem effective for preventing the onset of myopia if implemented successfully in schools and homes. While environmental interventions and spectacles are regarded as generally safe, pharmacological interventions, contact lenses, and RLRL may be associated with adverse effects. All interventions, except for behavioral change, are tied to moderate to high expenditures.

CONCLUSION

Our review suggests that myopia control interventions are recommended and prescribed on the basis of accessibility and clinical practice patterns, which vary widely around the world. Clinical trials indicate short- to medium-term efficacy in reducing myopia progression for various interventions, but none have demonstrated long-term effectiveness in preventing high myopia and potential complications in adulthood. There is an unmet need for a unified consensus for strategies that balance risk and effectiveness for these methods for personalized myopia management.

Associations of meeting 24-hour movement behavior guidelines with prescribed eyeglasses/contact lenses among children and adolescents

BACKGROUND

Vision health is crucial for many aspects of life especially in developing populations such as children and adolescents. However, there is a high proportion of children and adolescents who suffer from visual impairments. Notably, accumulating evidence indicates that meeting the 24-hour movement behaviors (24-HMB) guidelines is associated with positive physical and mental health outcomes in children and adolescents. However, the relationship between being prescribed eyeglasses/contact lenses and meeting the 24-HMB guidelines has yet to be investigated. Thus, this study aimed to address this gap in the existing literature by using the 2021 National Survey of Children's Health (NSCH) dataset.

METHODS

In this cross-sectional study, data was retrieved from the 2021 NSCH. A total of 14,193 U.S. children and adolescents aged between 6 and 17 years were included for data analyses. We used items of the NSCH concerning the 24-HMB guidelines (i.e., physical activity, screen time, and sleep duration) and prescription of eyeglasses/contact lenses that were answered by the legal guardian of the children. Binary logistic regression was performed to investigate whether meeting the 24-HMB guidelines is associated with prescription eyeglasses/contact lenses and whether wearing eyeglasses/contact lenses predicts adherence to the 24-HMB guidelines among children and adolescents.

RESULTS

More than half of the participants (59.53%) wore eyeglasses/contact lenses and only 8.40% of them met all three of the 24-HMB guidelines. Compared to meeting none of the 24-HMB guidelines, meeting one (OR = 0.76, 95% CI = 0.62-0.93, p = 0.008), two (OR = 0.54, 95% CI = 0.43-0.67, p < 0.001), and all three 24-HMB guidelines (OR = 0.47, 95% CI = 0.34-0.64, p < 0.001) were associated with a lower risk of being prescribed eyeglasses/contact lenses among children and adolescents.

CONCLUSIONS

The findings of the current study provided evidence that the prevalence of U.S. children and adolescents aged between 6 and 17 years who wore eyeglasses/contact lenses was relatively high. Furthermore, meeting the 24-HMB guidelines was associated with a lower risk of being prescribed eyeglasses/contact lenses. Future studies focusing on the effects of 24-HMB interventions on vision health among children and adolescents are needed to better inform public health actions.

How can we better evaluate paediatric progression of myopia and associated risk factors? Lessons from the COVID-19 pandemic: A systematic review

PURPOSE

During the COVID-19 pandemic, home-based and remote learning-particularly using electronic devices-was rapidly pushed out. Increased near-work, screen time exposure and lack of outdoor time are risk factors that contribute to childhood myopia, but it is difficult to adopt recommendations from prior publications as a consistent limitation in the literature is the heterogeneity of research methodology. This review seeks to systematically evaluate how observational studies published during the pandemic have quantified and measured risk factors and myopia in school-going children and adolescents.

METHODS

Three scientific databases (PubMed, CINAHL, Scopus) were systematically searched from March 2020 to April 2022. Findings from relevant studies were descriptively summarised in relation to the PICOS-based objective of the review.

RESULTS

The final sample of 13 studies included research from six countries and comprised 1 411 908 children and adolescents. The majority of studies (N = 10; 76.9%) used spherical equivalent refraction (SER) of -0.5 dioptres or lower as a common definition of myopia. Most studies (77.8%) measuring screen time exposure found it higher during COVID-19 compared to pre-COVID, but only one study used objective measurement of screen time. The average critical appraisal score of the sample was only 66.1%, with a considerable number of studies failing to identify and adjust for potential confounders.

CONCLUSION

Future studies should consider emergent objective and validated measures of risk factors, account for potential a priori confounders and covariates and ensure more representativeness in the sociodemographic makeup of their samples.

Ciliary muscles contraction leads to axial length extension--The possible initiating factor for myopia

PURPOSE

This study aimed to investigate the underlying factors driving the onset of myopia, specifically the role of the ciliary muscle's contraction in the elongation of the axial length of the eye.

METHODS

The retrospective study was conducted utilizing data from three ophthalmic centers in Shanghai and Beijing. Both Chinese and Caucasian children were involved. The axial length of the subjects' eyes was measured in both relaxed and contracted state of the ciliary muscle. A comprehensive mechanical model was also developed to observe the influence of ciliary muscle contraction on the axial length.

RESULTS

This study included a sample of 198 right eyes of 198 myopic children. Of these, 97 were male and 101 were female, 126 were of Chinese ethnicity and 72 were Caucasian. The age of onset for myopia ranged from 5.9 to 16.9 years old. The axial length of the eye decreased 0.028 ± 0.007mm following dilation, indicating relaxation of the ciliary muscle (t paired student = 15.16, p = 6.72 x 10-35). In contrast, ciliary muscle contraction resulted in an increase in axial length. Considering proportionality, a significant 90.4% (179 eyes) exhibited a reduced axial length, while a minor 9.6% (19 eyes) demonstrated an increase post-mydriasis. Finite element modeling demonstrated that muscle contraction caused a tension force that transmits towards the posterior pole of the eye, causing it to extend posteriorly.

CONCLUSION

The contraction of the ciliary muscle leads to an extension of the axial length. This could potentially be the initiating factor for myopia.

Analysis of factors related to the development of ocular biometric parameters in Chinese children aged 6-10 years: a cross-sectional study

OBJECTIVES

Emmetropia depends on the precise coordination of ocular biometry, including axial length (AL), corneal curvature, lens thickness and anterior chamber depth (ACD). Disruption of this coordination leads to refractive errors such as myopia. This article aimed to determine the factors affecting ocular biometry and myopia development in young children.

DESIGN

A cross-sectional study.

SETTING

This study was conducted in a primary school in the Yanqing district of Beijing, China.

PARTICIPANTS

792 students in grades 1-3 without hyperopia (>+2.00 D), strabismus, or amblyopia were selected.

EXCLUSIONS

students had conditions affecting best corrected visual acuity and whose guardians refused to provide informed consent. Ocular biometric measurements and non-cycloplegia autorefraction were performed. The questionnaire addressed factors such as perinatal factors and environmental factors.

INTERVENTIONS

None.

PRIMARY AND SECONDARY OUTCOMES

Ocular biometry and myopia.

RESULTS

According to the multivariate logistic regression analysis, electronic screen use >2 hours/day (OR=2.175, p=0.013), paternal myopia (OR=1.761, p=0.002), maternal myopia (OR=1.718, p=0.005), taller height (OR=1.071, p<0.001), maternal education (OR=0.631, p=0.012) and maternal gestational hypertension (OR=0.330, p=0.042) were associated with myopia. AL was affected by female sex (OR=0.295, p<0.001), older age (OR=1.272, p=0.002) and taller height (OR=1.045, p<0.001). Female sex (OR=0.509, p<0.001), taller height (OR=1.046, p<0.001), use of electronic screens >2 hours each day (OR=3.596, p<0.001) and time spent outdoors >2 hours each day (OR=0.431, p=0.001) influenced ACD incidence. Central corneal thickness (CCT) was associated with older age (OR=1.113, p=0.008), paternal education (OR=1.474, p=0.007), premature birth (OR=0.494, p=0.031), history of blue light therapy in infancy (OR=0.636, p=0.041) and history of incubator therapy in infancy (OR=0.263, p=0.009). Only sex influenced corneal curvature.

CONCLUSIONS

The factors associated with myopia were partly related to ACD and AL, and perinatal factors were associated with myopia and CCT.

TRIAL REGISTRATION NUMBER

ChiCTR2200065398.

Risk factors for myopia among children and adolescents: an umbrella review of published meta-analyses and systematic reviews

AIMS

To identify potential risk factors for myopia in children and adolescents and assess the credibility of each evidence, providing reference for the development of myopia prevention strategies.

METHODS

We searched PubMed, Web of Science and Embase databases from inception to April 2022 to find systematic reviews or meta-analyses investigating the relationship between potential risk factors and myopia, and conducted an umbrella review. We recalculated the pooled effect sizes and 95% CIs of each potential risk factor through random-effects model, and reported its 95% prediction interval and between-study heterogeneity. Small-study effect and excess of significance bias were assessed to reveal potential publication bias.

RESULTS

Twelve publications were included in this umbrella review, including eight meta-analyses and four qualitative systematic reviews. Twenty-two factors were identified, of which 16 were analysed quantitatively. Ten factors showed statistically significant association with myopia. Myopia in one or two parents and per additional hour of time spend outdoors per week were rated as highly suggestive evidence. Near work and gender were evaluated as suggestive evidence. The other five factors are weak evidence.

CONCLUSIONS

We found several risk factors for myopia with different levels of evidence, of which parental myopia presented the strongest association with myopia in children and adolescents. Our findings contribute to a better understanding of the association between potential risk factors and myopia among children and adolescents and are important for informing parenting, education, clinical practice guidelines and public health policy.

PROSPERO TRIAL REGISTRATION NUMBER

CRD42022333053.

Refractive and corneal astigmatism in Chinese 4-15 years old children: prevalence and risk factors

BACKGROUND

To investigate the prevalence and risk factors of refractive astigmatism (RA) and corneal astigmatism (CA) in preschool children and school-aged children in Shanghai, China.

METHODS

In this school-based, cross-sectional study, 4-15 years old children across three learning stages of kindergarten, primary school, and junior high school underwent noncycloplegic autorefraction and completed comprehensive questionnaires involving time spent on daily homework and outdoor activities. Data from the right eyes were analysed.

RESULTS

Overall, 7084 children (mean ± standard deviation (SD) of age: 8.08 ± 3.11 years) were included, and the prevalence rates of RA/CA ( ≤ - 1.0 D) in children were 15.8%/64% in kindergartens, 16.5%/65% in primary schools, and 32.8%/76.9% in junior high schools. The magnitude and prevalence of RA and CA all increased with age or with learning stage (all P < 0.001). The presence of RA was associated with more myopic spherical power (odds ratio (OR) 0.956, P = 0.021), junior high school (OR 1.973, P < 0.001), longer homework time on weekdays (OR 1.074, P = 0.029), and shorter outdoor activity time on weekends (odds ratio 0.929, P = 0.013).

CONCLUSION

In the wide age range of 4 to 15 years, the magnitude and prevalence of RA and CA increased with the learning stage, and these increases mainly began at the primary school stage. Factors, including longer homework time and shorter outdoor time were correlated with the presence of RA.

Attitudes and knowledge of myopia management by Spanish optometrists

PURPOSE

To investigate the knowledge, training and clinical practice of Spanish optometrists about preventing and controlling myopia progression.

METHODS

A web-based questionnaire was distributed to Spanish optometrists through social networks, optometric professional bodies and one of the major Spanish optometrists' associations to assess practitioner perception, understanding, and self-reported clinical practice behavior related to myopia diagnosis and management.

RESULTS

A total of 534 optometrists with a mean age of 40.8 ± 10.3 years completed the survey. Most respondents have been practicing optometry for more than 20 years (89.8%), report having actively treated childhood myopia (82.4%), and are very concerned about the increasing frequency of pediatric myopia in their daily practice (85.3%). Almost all of the respondents (97.3%) agreed that the efficacy of treatment is related to the age at which it is prescribed, and more than half (53.6%) considered a progression higher than - 0.50 and up to - 1.00D as the minimum necessary to consider a myopia management option. Respondents who reported actively managing childhood myopia considered orthokeratology, atropine and soft-defocus contact lenses the most effective myopia control interventions. However, the most frequently prescribed form of myopia correction by Spanish optometrists was single-vision spectacles, followed by orthokeratology and soft-defocus contact lenses.

CONCLUSIONS

Spanish optometrists are very active in the management of myopia, especially by fitting orthokeratology lenses or dual-focus soft contact lenses for myopia control, but there is still potential for improvement in the methodology they follow for both the diagnosis and management of myopia.

Advances in myopia prevention strategies for school-aged children: a comprehensive review

Myopia has significantly risen in East and Southeast Asia, and the pathological outcomes of this condition, such as myopic maculopathy and optic neuropathy linked to high myopia, have emerged as leading causes of irreversible vision loss. Addressing this issue requires strategies to reduce myopia prevalence and prevent progression to high myopia. Encouraging outdoor activities for schoolchildren and reducing near-work and screen time can effectively prevent myopia development, offering a safe intervention that promotes healthier habits. Several clinical approaches can be employed to decelerate myopia progression, such as administering low-dose atropine eye drops (0.05%), utilizing orthokeratology lenses, implementing soft contact lenses equipped with myopia control features, and incorporating spectacle lenses with aspherical lenslets. When choosing an appropriate strategy, factors such as age, ethnicity, and the rate of myopia progression should be considered. However, some treatments may encounter obstacles such as adverse side effects, high costs, complex procedures, or limited effectiveness. Presently, low-dose atropine (0.05%), soft contact lenses with myopia control features, and orthokeratology lenses appear as promising options for managing myopia. The measures mentioned above are not necessarily mutually exclusive, and researchers are increasingly exploring their combined effects. By advocating for a personalized approach based on individual risk factors and the unique needs of each child, this review aims to contribute to the development of targeted and effective myopia prevention strategies, thereby minimizing the impact of myopia and its related complications among school-aged children in affected regions.

Optical Biometry Changes Throughout Childhood and Adolescence in Patients Wearing Ortho-K Lenses

Background

Orthokeratology has been shown to suppress progressive myopia in some children. We examine the changes in optical biometry parameters in orthokeratology (Ortho-K) patients, in a retrospective longitudinal study at a tertiary eye care center in Ann Arbor, MI, USA.

Methods

Optical biometry measurements obtained with the Lenstar LS 900 (Haag-Streit USA Inc, EyeSuite software version i9.1.0.0) were aggregated from 170 patients who had undergone Ortho-K for myopia correction between 5 and 20 years of age. Pre-intervention biometry measurements were compared with follow-up measurements done 6-18 months after initiation of Ortho-K. Linear mixed models were used to quantify associations in biometry changes with age of intervention allowing for correlation between measurements on two eyes of the same patient.

Results

A total of 91 patients were included in the study. Axial length increased through the age of 15.7 ± 0.84 years for Ortho-K patients at our center. The growth curve in our Ortho-K population was comparable to previously published normal growth curves in Wuhan and Germany populations. Corneal thickness and keratometry decreased at a stable rate regardless of age of intervention (-7.9 µm, 95% CI [-10.2, -5.7], p < 0.001).

Conclusion

In our population, Ortho-K did not appear to affect the overall trajectory of axial length progression when compared to normal growth curves, despite showing a previously described reduction in corneal thickness. As Ortho-K has been shown to have varying effects that differ from individual to individual, it continues to be important to reassess its effects on new populations to better understand its ideal uses.

Myopia in elementary school students in Eastern China during the COVID-19 pandemic

Background

Myopia is an increasingly serious public concern, particularly among primary school students. The prevalence of myopia and its influencing factors in primary school pupils in Eastern China during the COVID-19 pandemic had not been explored.

Methods

A randomly clustered sampling method was performed, and selected pupils from grade 1 to grade 3 in 15 primary schools in the Fenghua District of Zhejiang Province were included and given myopia screening and uniform questionnaire survey 1 year later.

Results

A total of 4,213 students completed the myopia screening and questionnaire survey. Myopia was diagnosed in 1,356 pupils, with a myopia incidence of 32.19%. The spherical equivalent (SE) refraction of the included pupils decreased on average by 0.50 ± 2.15 D 1 year later. The myopia rate was positively correlated with the increase of grade, in which the myopia rate among grade 3 students was the highest at 39.69%. The myopia rate among female students was higher than that among male students. Students residing in urban areas had a higher myopia rate than in rural areas. Maintaining an near work distance ≥33 cm was a significant protective factor (OR = 0.84, 95% CI: 0.74-0.96). Students with two myopic parents had a higher risk of myopia (OR = 1.61, 95% CI: 1.34-1.92).

Conclusion

During the COVID-19 pandemic, the myopia rate among early primary school students in Eastern China was high. More attention and implementation of interventions from health and education departments, such as training the development of good eye behavior, should be considered to strengthen the intervention of myopia in primary school students.

Baseline characteristics in the Israel refraction, environment, and devices (iREAD) study

The purpose of this study is to present baseline data from a longitudinal study assessing behavioral factors in three groups of boys in Israel with varying myopia prevalence. Ultra-Orthodox (N = 57), religious (N = 67), and secular (N = 44) Jewish boys (age 8.6 ± 1.4 years) underwent cycloplegic autorefraction and axial-length measurement. Time-outdoors and physical-activity were assessed objectively using an Actiwatch. Ocular history, educational factors, and near-work were assessed with a questionnaire. Group effects were tested and mixed effects logistic and linear regression were used to evaluate behaviors and their relationship to myopia. The prevalence of myopia (≤ - 0.50D) varied by group (ultra-Orthodox: 46%, religious: 25%, secular: 20%, P < 0.021). Refraction was more myopic in the ultra-Orthodox group (P = 0.001). Ultra-Orthodox boys learned to read at a younger age (P < 0.001), spent more hours in school (P < 0.001), spent less time using electronic devices (P < 0.001), and on weekdays, spent less time outdoors (P = 0.02). Increased hours in school (OR 1.70) and near-work (OR 1.22), increased the odds of myopia. Being ultra-Orthodox (P < 0.05) and increased near-work (P = 0.007) were associated with a more negative refraction. Several factors were associated with the prevalence and degree of myopia in young boys in Israel, including being ultra-Orthodox, learning to read at a younger age, and spending more hours in school.

Myopia risk behaviour related to the COVID-19 lockdown in Europe: The generation R study

PURPOSE

To battle the spreading of the COVID-19 virus, nationwide lockdowns were implemented during 2020 and 2021. Reports from China revealed that their strict home confinements led to an increase in myopia incidence. The Netherlands implemented a more lenient lockdown, which allowed children to go outside. We evaluated the association between COVID-19 restrictions, myopia risk behaviour and myopia progression in Dutch teenagers.

METHOD

A total of 1101 participants (mean age 16.3 ± 3.65 yrs) completed questionnaires about their activities before, during and after lockdown (March-October 2020). We used a repeated-measures ANOVA to compare time use between these time periods. Ocular measurements were acquired before the COVID-19 pandemic when participants were 13 years old; only 242 participants had ocular measurements at 18 years of age at the time of this analysis. Linear regression analyses were used to evaluate the association between lifestyle factors and myopia progression.

RESULTS

Children were on average 16.2 (1.03) years of age during lockdown. Total nearwork increased from 8.11 h/day to 11.79 h/day, and remained higher after lockdown at 9.46 h/day (p < 0.001). Non-educational nearwork increased by 2.22 h/day (+49%) during lockdown and was associated with faster axial length progression (B 0.002 mm/h/year; SE 0.001 p = 0.03). Before and during lockdown, the mean time spent outdoors was similar (1.78 h/day and 1.80 h/day, respectively). After lockdown, time spent outdoors decreased to 1.56 h/day (p < 0.001).

CONCLUSION

The Dutch lockdown significantly increased digitised nearwork in adolescents but did not affect outdoor exposure. The changes in time spent performing nearwork remained after the lockdown measures had ended. We expect that the COVID-19 pandemic may lead to an increase in myopia prevalence and progression in European children.

Near work, light levels and dioptric profile - Which factor dominates and influences the short-term changes in axial length?

PURPOSE

Given the agonistic nature of near work to promote axial elongation and the antagonistic nature of time outdoors to prevent myopia, we aimed to investigate the following: (a) how the short-term effect of near work performed outdoors (Experiment 1) influences axial length and (b) how near work performed in two different dioptric profiles (uncluttered and cluttered) alters the changes in central axial length (Experiment 2).

METHODS

Forty-six adults (age range: 19-32 years) participated in the study. In Experiment 1, 22 participants completed a 15-min distance task and a reading task in both the outdoor (~30,000 lux) and indoor (~70 lux) locations. In Experiment 2, 24 participants performed the same reading task at a study desk in uncluttered and cluttered reading environments. Pre- and post-task ocular biometry measurements were performed for each session using a non-contact biometer.

RESULTS

In Experiment 1, a significant increase in axial length from baseline was found after performing reading tasks in both outdoor (mean ± SEM: +12.3 ± 3.4 μm, p = 0.001) and indoor locations (+11.9 ± 3.1 μm, p = 0.001). In Experiment 2, axial length increased significantly from baseline to post reading task, in both uncluttered (+17.9 ± 3.5 μm, p < 0.001) and cluttered reading environments (+19.2 ± 2.9 μm, p < 0.001). No significant changes in axial length were observed either between outdoor and indoor locations (p = 0.92) or between the uncluttered and cluttered reading environment (p = 0.75).

CONCLUSION

Independent of light intensity (outdoor or indoor location) and dioptric profile of the near-work environment (uncluttered or cluttered), a 15-min reading task led to a significant increase in axial length. While the long-term effects of these findings need to be evaluated, practitioners should emphasise how near work can reduce the beneficial effects of time outdoors, while providing recommendations related to time outdoors for myopia control.

[Recommendations for Progressive Myopia in Childhood and Adolescence. Statement of the DOG, BVA and the Bielschowsky Society for Strabismus Research and Neuroophthalmology - Status June 2022]

Since the last and at the same time first statement of the German ophthalmological societies on the possibilities of reducing myopia progression in childhood and adolescence, many new details and aspects have emerged in clinical research. This second statement updates the previous document and specifies the recommendations on visual and reading behavior as well as on pharmacological and optical therapy options, which have been both refined and newly developed in the meantime.

[Recommendations for progressive myopia in childhood and adolescence. Statement of the DOG, BVA and the Bielschowsky Society for Strabismus Research and Neuroophthalmology : Status June 2022]

Since the last and at the same time first statement of the German ophthalmological societies on the possibilities of reducing myopia progression in childhood and adolescence, many new details and aspects have emerged in clinical research. This second statement updates the previous document and specifies the recommendations on visual and reading behavior as well as on pharmacological and optical therapy options, which have been both refined and newly developed in the meantime.

Fighting Myopia with Intermittent Nearwork Breaks: 20 Seconds Every 20 Minutes Might Not Be Enough Time

SIGNIFICANCE

Practitioners commonly prescribe the 20/20/20 rule with hopes that, if patients follow it, they will reduce their myopic progression. This clinical perspective provides evidence that 20-second break from nearwork every 20 minutes are not enough time to impact ocular growth.The ongoing myopia epidemic is a major public health crisis. Although the correlation between nearwork tasks such as reading, computers, and smartphones and myopia development is controversial, multiple lines of research suggest that sustained nearwork contributes to myopia development. Clinicians have proposed that children should take short breaks from nearwork with a 20-second break every 20 minutes being a common suggestion. Animal model data do strongly support the idea that multiple short breaks across time can cancel out the effects of longer periods of myopia-promoting activities. However, the animal model data also suggest that repeated episodes of 20 seconds are ineffective at reducing myopia development and instead indicate that sustained breaks of 5 minutes or more every hour are needed to negate myopiagenic effects.

Myopia: why the retina stops inhibiting eye growth

In myopia, the eye grows too long, and the image projected on the retina is poorly focused when subjects look at a distance. While the retina normally controls eye growth by visual processing, it seems to give up during myopia development. But what has changed? To determine whether the sharp image is in front or behind the retinal plane, a comparison of image sharpness in red and blue would provide a reliable cue because focal planes are about 1.3 D apart due to longitudinal chromatic aberration (LCA). However, up to now, it could not be demonstrated that the retina does, in fact, such a comparison. We used a new approach: movies were digitally filtered in real time to present either the blue channel of the RGB color format unfiltered while green and red were blurred ("blue in focus"), or the red channel was unfiltered while green and blue were blurred ("red in focus") accordingly to the human LCA function. Here we show that, even though filtered movies looked similar, eyes became significantly shorter when the movie was sharp in the red plane but became longer when it was presented sharp in the blue plane. Strikingly, the eyes of young subjects who were already myopic did not respond at all-showing that their retina could no longer decode the sign of defocus based on LCA. Our findings resolve a long-standing question as to how the human retina detects the sign of defocus. It also suggests a new non-invasive strategy to inhibit early myopia development: keeping the red image plane on a computer screen sharp but low pass filtering the blue.

Short-Term Exposure to Violet Light Emitted from Eyeglass Frames in Myopic Children: A Randomized Pilot Clinical Trial

Violet light (VL), 360−400 nm wavelength, is contained in the sunlight and is an effective element for myopia suppression. This study is to investigate the safety and efficacy of novel eyeglasses that emit VL from the frames. This is a double-masked, randomized, pilot clinical trial conducted in a clinic in Japan. Forty-three children with myopia were enrolled. Participants were randomly assigned to two groups, wearing VL-emitting eyeglass frames (VLf) that emitted VL of 310 μW/cm2 (VLf group, n = 22) or pseudo-placebo eyeglass frames with a minimal emission of VL (<10 μW/cm2) (control group, n = 21). The exposure time was 3 h per day. The primary outcomes were visual acuity, tear film break-up time, corneal endothelial cell density, and the slit-lamp/fundus examinations. The secondary outcome was the 6-month changes in the axial lengths and cycloplegic refractions. Forty-one (95%) participants were included; twenty-one in the VLf group and twenty in the control group. No significant differences were seen in any safety evaluation. Significant changes were seen in axial elongation, choroidal thickness, and cycloplegic refractions in the subgroup analysis of 8- to 10-year-old children (p < 0.05), but otherwise no significant differences were seen. The VLf showed short-term safety and effectiveness against myopia progression.

Associations between reading and writing postures and myopia among school students in Ningbo, China

Background

We conducted this study to investigate the prevalence of myopia among school students in Ningbo and to explore the associations between reading and writing postures and myopia.

Methods

A population-based and cross-sectional study was conducted, and 3,256 school students aged 8-19 years were recruited. Each enrolled subject was assessed for uncorrected distance visual acuity (UDVA) using a standard logarithmic visual acuity E-chart and a non-cycloplegic autorefraction examination. Self-administered questionnaires were used to investigate myopia-related reading and writing postures and behavioral habits among school students.

Results

The prevalence of myopia among primary school, middle school, and high school students was 61.49, 81.43, and 89.72%, respectively. Regarding the associations between reading and writing postures and myopia, we identified that a reading distance >33 cm is a protective factor for myopia in female students [odds ratio (OR) = 0.31, 95% confidence interval (CI) = 0.15-0.64], in both primary school (OR = 0.55, 95% CI = 0.30-0.99) and middle school (OR = 0.37, 95% CI = 0.15-0.90).

Conclusions

A reading distance >33 cm can be used as an additional measure to prevent and control myopia. Proper postural measures for reading and writing may have educational and public health benefits.

Outbreak of COVID-19-Related Myopia Progression in Adults: A Preliminary Study

PURPOSE

The COVID-19 pandemic has necessitated specific public health measures, resulting in the alteration of lifestyles, such as increased digital screen time and fewer outdoor activities. Such conditions have increased the progression of myopia in children. However, no investigation of myopia progression in early adulthood has been conducted during this period. Consequently, this study aimed to evaluate the outbreak of COVID-19-related myopia progression among adults at an optometry clinic during the COVID-19 pandemic.

MATERIALS AND METHODS

This was a retrospective cohort study in which participants aged 18-25 years who first visited (baseline) the optometry clinic between June 2019 and March 2020 were recruited for follow-up from November 2021 to March 2022. Spherical equivalent refraction (SER), uncorrected distance visual acuity (UCDVA), and binocular cross cylinder (BCC) were recorded at baseline and a follow-up visit. Using questionnaires, a survey was conducted to assess the lifestyle changes that transpired during the COVID-19 pandemic.

RESULTS

In total, 37 participants with a mean age of 22.5±1.4 years were enrolled, of which 89.2% were female. Following the outbreak of the COVID-19 pandemic, most participants self-reported increased daily use of digital devices (89.2%), online education (86.5%), and spending more time at home (94.6%), which increased by approximately 7.6±3.2 hours, 5.9±1.7 hours, and 13.2±7.5 hours, respectively. There were statistically significant differences between SER and BCC at baseline and after approximately 2 years of the COVID-19 pandemic (p < 0.05). The mean two-year myopia progression was -0.59±0.67 D (Maximum = 0.00 D, Minimum = -3.38 D).

CONCLUSION

This study revealed that myopia could progress during adulthood among those who have lived under public health measures intended to address the COVID-19 pandemic.

Systematic review and meta-analysis of myopia prevalence in African school children

Purpose

Increased prevalence of myopia is a major public health challenge worldwide, including in Africa. While previous studies have shown an increasing prevalence in Africa, there is no collective review of evidence on the magnitude of myopia in African school children. Hence, this study reviews the evidence and provides a meta-analysis of the prevalence of myopia in African school children.

Methods

This review was conducted using the 2020 Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Five computerized bibliographic databases, PUBMED, Scopus, Web of Science, ProQuest, and Africa Index Medicus were searched for published studies on the prevalence of myopia in Africa from 1 January 2000 to 18 August 2021. Studies were assessed for methodological quality. Data were gathered by gender, age and refraction technique and standardized to the definition of myopia as refractive error ≥ 0.50 diopter. A meta-analysis was conducted to estimate the prevalence. Significant heterogeneity was detected among the various studies (I² >50%), hence a random effect model was used, and sensitivity analysis was performed to examine the effects of outliers.

Results

We included data from 24 quality assessed studies, covering 36,395 African children. The overall crude prevalence of myopia over the last two decades is 4.7% (95% CI, 3.9–5.7) in African children. Although the prevalence of myopia was slightly higher in females (5.3%, 95%CI: 4.1, 6.5) than in males (3.7%, 95% CI, 2.6–4.7; p = 0.297) and higher in older [12–18 years 5.1% (95% CI, 3.8–6.3) than younger children (aged 5–11 years, 3.4%, 95% CI, 2.5–4.4; p = 0.091), the differences were not significant. There was a significantly lower prevalence of myopia with cycloplegic compared with non-cycloplegic refraction [4.2%, 95%CI: 3.3, 5.1 versus 6.4%, 95%CI: 4.4, 8.4; p = 0.046].

Conclusions

Our results showed that myopia affects about one in twenty African schoolchildren, and it is overestimated in non-cycloplegic refraction. Clinical interventions to reduce the prevalence of myopia in the region should target females, and school children who are aged 12–18 years.

Recent understanding of binocular vision in the natural environment with clinical implications

Technological advances in recent decades have allowed us to measure both the information available to the visual system in the natural environment and the rich array of behaviors that the visual system supports. This review highlights the tasks undertaken by the binocular visual system in particular and how, for much of human activity, these tasks differ from those considered when an observer fixates a static target on the midline. The everyday motor and perceptual challenges involved in generating a stable, useful binocular percept of the environment are discussed, together with how these challenges are but minimally addressed by much of current clinical interpretation of binocular function. The implications for new technology, such as virtual reality, are also highlighted in terms of clinical and basic research application.