Myopia and level of education: results from the Gutenberg Health Study

Bi-Gaussian analysis reveals distinct education-related alterations in spherical equivalent and axial length-results from the Gutenberg Health Study

PURPOSE

The aim of this study is to investigate the distribution of spherical equivalent and axial length in the general population and to analyze the influence of education on spherical equivalent with a focus on ocular biometric parameters.

METHODS

The Gutenberg Health Study is a population-based cohort study in Mainz, Germany. Participants underwent comprehensive ophthalmologic examinations as part of the 5-year follow-up examination in 2012-2017 including genotyping. The spherical equivalent and axial length distributions were modeled with gaussian mixture models. Regression analysis (on person-individual level) was performed to analyze associations between biometric parameters and educational factors. Mendelian randomization analysis explored the causal effect between spherical equivalent, axial length, and education. Additionally, effect mediation analysis examined the link between spherical equivalent and education.

RESULTS

A total of 8532 study participants were included (median age: 57 years, 49% female). The distribution of spherical equivalent and axial length follows a bi-Gaussian function, partially explained by the length of education (i.e., < 11 years education vs. 11-20 years). Mendelian randomization indicated an effect of education on refractive error using a genetic risk score of education as an instrument variable (- 0.35 diopters per SD increase in the instrument, 95% CI, - 0.64-0.05, p = 0.02) and an effect of education on axial length (0.63 mm per SD increase in the instrument, 95% CI, 0.22-1.04, p = 0.003). Spherical equivalent, axial length and anterior chamber depth were associated with length of education in regression analyses. Mediation analysis revealed that the association between spherical equivalent and education is mainly driven (70%) by alteration in axial length.

CONCLUSIONS

The distribution of axial length and spherical equivalent is represented by subgroups of the population (bi-Gaussian). This distribution can be partially explained by length of education. The impact of education on spherical equivalent is mainly driven by alteration in axial length.

Global prevalence of myopic macular degeneration in general population and patients with high myopia: A systematic review and meta-analysis

The prevalence of myopic macular degeneration (MMD) in the general population and patients with high myopia worldwide has not been fully investigated. Therefore, we screened all population-based studies that reported the prevalence of MMD, and pooled prevalence of MMD using a random-effect model. Subgroup analyses were performed to explore the differences in MMD prevalence in the general population and patients with high myopia according to ethnicity, region of residence (urban/rural), and grading system. Finally, 16 studies were included in this meta-analysis. Results obtained from 2,963 patients from seven countries on four continents indicated that the pooled prevalence of MMD in patients with high myopia was 49.0% (95% CI: 31.5%-66.7%). Results obtained from 71,052 participants from 10 countries on four continents suggested that the pooled prevalence of MMD in the general population was 1.7% (95% CI: 1.1%-2.6%). In the general population, living in urban areas and East Asians were associated with a high prevalence of MMD. Among patients with high myopia, only East Asians were at a higher risk of developing MMD. In conclusion, MMD was particularly prevalent in patients with high myopia. Compared with Europeans, East Asians (Chinese and Japanese) have a higher propensity of developing MMD, both in the general population and in patients with high myopia. It remains unclear whether the higher prevalence of MMD in patients with high myopia in East Asia is caused by differences in given age or given degree of myopia.Systematic review registration number: 202270014 (INPLASY.COM).

Prevalence of refractive errors in population aged 50 years and over: The Gilan eye study

PURPOSE

To describe the prevalence of refractive error (RE) and its association with other environmental and health factors among population aged ≥50 years who lived in Gilan, Iran in 2014.

METHODS

In this population-based cross-sectional study, 3281 individuals aged ≥50 years living in Gilan for at least 6 months were enrolled. The prevalence of different types of REs including myopia (spherical equivalent (SE)≤-0.50D), high myopia (SE ≤ -6.00D), hyperopia (SE≥ + 0.50D), high hyperopia (SE≥ + 3.00D), astigmatism (cylinder < -0.50D) and high astigmatism (cylinder < -2.25D) were determined. Anisometropia was defined as the SE difference of ≥1.00D between the two eyes. Associated factors including age, body mass index (BMI) and education were also studied.

RESULTS

2587 eligible individuals (58% female subjects) with the mean age of 62.6 ± 8.8 years participated (87.6% response rate). The prevalence of myopia, hyperopia and astigmatism was 19.2%, 48.6% and 57.4%, respectively. 3.6% high hyperopia, 0.5% high myopia and 4.5% high astigmatism were identified. The positive simultaneous effects3 of older age (Odds Ratio (OR) = 3.14), nuclear (OR = 1.71) and posterior subcapsular (OR = 1.61) cataracts as well as the negative effects of higher levels of education (OR = 0.28) were obtained on myopia. Higher BMI was found as a risk factor for hyperopia (OR = 1.67), while older patients were less likely to be hyperopic (OR = 0.31).

CONCLUSION

Higher incidence of myopia and astigmatism was found in patients aged over 70 years. It was also found that patients at older ages who suffered with cataracts were at a higher risk of myopia, while elderly people with greater BMI were at a higher risk of hyperopia.

The influence of the environment and lifestyle on myopia

BACKGROUND

Myopia, commonly known as near-sightedness, has emerged as a global epidemic, impacting almost one in three individuals across the world. The increasing prevalence of myopia during early childhood has heightened the risk of developing high myopia and related sight-threatening eye conditions in adulthood. This surge in myopia rates, occurring within a relatively stable genetic framework, underscores the profound influence of environmental and lifestyle factors on this condition. In this comprehensive narrative review, we shed light on both established and potential environmental and lifestyle contributors that affect the development and progression of myopia.

MAIN BODY

Epidemiological and interventional research has consistently revealed a compelling connection between increased outdoor time and a decreased risk of myopia in children. This protective effect may primarily be attributed to exposure to the characteristics of natural light (i.e., sunlight) and the release of retinal dopamine. Conversely, irrespective of outdoor time, excessive engagement in near work can further worsen the onset of myopia. While the exact mechanisms behind this exacerbation are not fully comprehended, it appears to involve shifts in relative peripheral refraction, the overstimulation of accommodation, or a complex interplay of these factors, leading to issues like retinal image defocus, blur, and chromatic aberration. Other potential factors like the spatial frequency of the visual environment, circadian rhythm, sleep, nutrition, smoking, socio-economic status, and education have debatable independent influences on myopia development.

CONCLUSION

The environment exerts a significant influence on the development and progression of myopia. Improving the modifiable key environmental predictors like time spent outdoors and engagement in near work can prevent or slow the progression of myopia. The intricate connections between lifestyle and environmental factors often obscure research findings, making it challenging to disentangle their individual effects. This complexity underscores the necessity for prospective studies that employ objective assessments, such as quantifying light exposure and near work, among others. These studies are crucial for gaining a more comprehensive understanding of how various environmental factors can be modified to prevent or slow the progression of myopia.

Relationship between visual impairment and school entrance age in rural China

CLINICAL RELEVANCE

Children with uncorrected visual impairment have lower scores on various motor and cognitive tests. Exploring the association between visual impairment and school entrance age among school children in rural China may assist in enhancing the visual health of early-entry school students.

BACKGROUND

Educational pressures may play a role in the visual health of students. School entrance age is associated with educational pressures. This study explored whether school entrance age can contribute to visual impairment among younger generations.

METHODS

A cross-sectional study was conducted with 17,510 students from 252 primary schools in two prefectures in western China. Information on the sampled students was collected through questionnaires and vision examinations. The relationship between visual impairment and school entrance age was further analysed by multiple regression. The school entrance age was classified as early-entry and late-entry, early-entry was defined as students entering school at the age 6 years.

RESULTS

The results showed that the myopia rate of early-entry students (26.92%) was higher than late-entry students (23.86%). Multiple regression showed that visual impairment increased with the earlier age of school entry (P = 0.044). The prevalence of myopia was also significantly higher in higher grades for children of the same age. The prevalence of myopia in 10-year-old and 11-year-old fourth- and fifth-grade students was 20.6% to 30.5%, 21.7% to 27.4% (P < 0.001). The near work with eyes was significantly different among children of the same age in different grades during this study (P < 0.001).

CONCLUSION

Myopia is related to the school entrance age of children. Children who start school earlier are more likely to suffer from myopia. Educational pressures and digital screens may play a role in the association. Changes in the current education mode by reducing the study burden in the early years of learning may be significant.

Risk Factors for Myopia: A Review

Due to the myopia prevalence increase worldwide, this study aims to establish the most relevant risk factors associated with its development and progression. A review search was carried out using PubMed, Web of Science, and Scopus databases to identify the main myopia risk factors. The inclusion criteria for the articles were those related to the topic, carried out in subjects from 5 to 30 years, published between January 2000 and May 2023, in English, and with the full text available. Myopia etiology has proven to be associated with both genetic and environmental factors as well as with gene-environment interaction. The risk of developing myopia increases in children with myopic parents (one parent ×2 times, two parents ×5 times). Regarding environmental factors, education is the main risk factor correlated with myopia prevalence increase. Further, several studies found that shorter distance (<30 cm) and longer time spent (>30 min) for near work increase the risk of myopia. Meanwhile, increased outdoor activity (>40 min/day) has been shown to be a key factor in reducing myopia incidence. In conclusion, the interventional strategy suggested so far to reduce myopia incidence is an increase in time outdoors and a reduction in the time spent performing near-work tasks.

L-opsin expression in chickens is similarly reduced with diffusers and negative lenses

Previous studies have shown that the expression of L- and M-opsins was reduced in chicken retina when eyes were covered with diffusers. The purpose of the current study was to find out whether this is a result of altered spatial processing during development of deprivation myopia or merely a consequence of light attenuation by the diffusers. Therefore, retinal luminances were matched by neutral density filters in fellow eyes that served as controls for diffuser-treated eyes. Furthermore, the effects of negative lenses on opsins expression were studied. Chickens wore diffusers or -7D lenses for a period of 7 days and refractive state and ocular biometry were measured at the beginning and at the end of the experiment. Retinal tissue was extracted from both eyes to quantify L-, M- and S-opsins expression by qRT-PCR. It was found that L-opsin expression was significantly lower in eyes wearing diffusers, compared to fellow eyes covered with neutral density filters. Interestingly, L-opsin was also reduced in eyes wearing negative lenses. In summary, this study shows that L-opsin expression is reduced due to the loss of high spatial frequencies and general contrast reduction in the retinal image, rather than by a decline in retinal luminance. Moreover, the fact that L-opsin was similarly reduced in eyes treated with negative lenses and diffusers suggests the existence of a common pathway for emmetropization, but it could also be just a consequence of reduced high spatial frequencies and lower contrast.

Factors associated with myopia in 19-year-old adult men in Korea between 2014 and 2020

Numerous environmental factors that influence myopia have been studied, but only few factors have been definitively identified. We examined factors influencing myopia using data from 2014 to 2020 physical examinations received from the Korean Military Manpower Administration. We used the Cochran-Armitage trend test to investigate the annual prevalence of myopia and high myopia. To determine risk factors for myopia, logistic regression was performed. The data of 2,215,126 19-year-old Korean men were examined. The myopia and high myopia prevalences showed significant annual increases; in 2020, these prevalences were 58.9% and 18.0%, respectively. The myopia prevalence was high when the birth season was spring, education level was high, height was small, weight and body mass index (BMI) were low (< 18.5 kg/m²), and color vision was normal (all, p < 0.05). The high myopia prevalence was high when the birth season was spring, education level was high, height was tall, weight and BMI were low (< 18.5 kg/m²), and color vision was normal (all, p < 0.05). The prevalence of myopia and high myopia in this population is increasing annually. The risk of both conditions increased when the birth season was spring, education level was high, BMI was low, color vision was normal, and diabetes was present.

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.

Differences in visual stimulation between reading and walking and implications for myopia development

Visual input plays an important role in the development of myopia (nearsightedness), a visual disorder that blurs vision at far distances. The risk of myopia progression increases with the time spent reading and decreases with outdoor activity for reasons that remain poorly understood. To investigate the stimulus parameters driving this disorder, we compared the visual input to the retina of humans performing two tasks associated with different risks of myopia progression, reading and walking. Human subjects performed the two tasks while wearing glasses with cameras and sensors that recorded visual scenes and visuomotor activity. When compared with walking, reading black text in white background reduced spatiotemporal contrast in central vision and increased it in peripheral vision, leading to a pronounced reduction in the ratio of central/peripheral strength of visual stimulation. It also made the luminance distribution heavily skewed toward negative dark contrast in central vision and positive light contrast in peripheral vision, decreasing the central/peripheral stimulation ratio of ON visual pathways. It also decreased fixation distance, blink rate, pupil size, and head-eye coordination reflexes dominated by ON pathways. Taken together with previous work, these results support the hypothesis that reading drives myopia progression by understimulating ON visual pathways.

Cognitive workload affects ocular accommodation and pupillary response

SIGNIFICANCE

Cognitive involvement in reading causes variations in the tonus of autonomic nerve system. The aim of this study was to examine the effect of short-term cognitive load on accommodation and pupils' absolute values and temporal variability in test persons performing three different types of tasks.

PURPOSE

We aimed to show how cognitive tasks of different type and difficulty level affect accommodation and pupil behavior during a short time interval.

METHODS

Participants (n = 58; mean age 16.4 years, SD = 0.56) performed reading from a 10-inch LCD screen placed at 40 cm distance. Three different types of tasks (numerical, textual, and the Stroop task), each at three different levels of cognitive load were introduced. Participants had 90 s to complete each task. Accommodative and pupillary responses were measured with videoretinoscope Power Refractor 3 at 50 Hz.

RESULTS

Pupil size was largest in the Stroop task (M = 5.20 mm, SD = 0.75 mm), followed by the numerical tasks (M = 5.02 mm, SD = 0.72 mm) and textual tasks (M = 4.78 mm, SD = 0.71 mm). Accommodative fluctuations - measured as accommodation SD - were largest in the textual tasks (M = 0.67 D, SD = 0.34 D), followed by the numerical tasks (M = 0.61 D, SD = 0.40 D) and the Stroop task (M = 0.52 D, SD = 0.21 D).

CONCLUSIONS

In our experiment, short-term cognitive load was associated with altered pupillary and accommodative response to near tasks. In conflicting tasks (Stroop) or in performing continuing calculations, the pupils were larger; in tasks requiring logical reasoning, the accommodative fluctuations were greater. These effects can potentially be associated with current near-point stress and myopia growth models.

Ocular biological parameters and prevalence of myopia in vocational high school and general high school in China

Significance

Higher prevalence of myopia is possibly associated with more extended schooling schedules. Therefore, adjustments to high school curricula may aid in reducing the prevalence of myopia among adolescents.

Purpose

To investigate the prevalence of myopia among 15- to 18-year-old adolescents in Tianjin, China, and to evaluate the impact of different educational schedules on the prevalence of myopia among high school students.

Methods

This is a school-based epidemiological study with a cross-sectional design. Ocular biological parameters and noncycloplegic photorefraction were examined using optical biometry devices and photoscreener devices. Each student’s spherical equivalent (SE) and ocular biometry were recorded, and the prevalence of myopia was calculated.

Results

A total of 2,867 participants (1,519 males and 1,348 females) were tested for non-cycloplegic refraction, axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD) and lens thickness (LT). In this research, the overall prevalence of myopia was 81.6%, with high myopia accounting for 11.8%. Myopia prevalence was substantially higher in general high schools than in vocational high schools, with 86.1 and 70.1%, respectively. There were no significant differences in the prevalence of myopia (p = 0.744) or high myopia (p = 0.851) across the three vocational school years. In the general high school, however, there was an increase of 4.6% (p &lt; 0.05) in myopia prevalence between year 10 and year12.

Conclusion

Comparing vocational and standard high school students, there are considerable disparities in prevalence of myopia, spherical equivalent, and ocular biological parameters. The prevalence of myopia and high myopia increased among standard high school students, but remained relatively consistent among students in vocational schools.

Objective Quantification and Topographic Dioptric Demand of Near-Work

Purpose

The assessment of myopigenic environmental risk factors such as near-work relies on subjective data. Although diaries and questionnaires on near-work show correlation to some degree, it remains unknown how they may correspond to ground truth. This is an important consideration because valid estimates of near-work have great utility for understanding the mechanisms by which dioptric demand drives excessive eye-growth, which is not yet entirely understood. To this end, we assessed a novel eye-tracking system to quantify near-work.

Method

We compared subjective entries from diaries to objective data on accommodative demand acquired with a three-dimensional eye-tracker in 20 participants. Each test involved approximately one-hour exposure to ecological near-work environments. Furthermore, topographical dioptric demand maps were computed in retinal coordinates.

Results

Our study suggests a frequent mismatch between objectively and subjectively labeled data of near-work tasks (concordance 74.6%). Objective and subjective estimates of dioptric demand showed a moderate correlation and were not significantly different (R2 = 0.59, P = .35). Instead, accommodative demand with an agreement between objective and subjective near-work labels showed a high correlation and were significantly different (R2 = 0.79, P = .016). The accumulated topographical dioptric demand of ecological near-work environments did not present myopigenic defocus stimuli to the retina periphery. Thus extreme close-up near-work presented peripheral defocus stimuli that have been proposed to curb excessive eye growth.

Conclusions

The proposed objective measurement method may provide improvements over subjective methods for estimating near-work parameters.

Translational Relevance

The topographic dioptric demand maps highlight a possible conflict of causal mechanisms of the two myopia models: "excessive near-work" and "peripheral optical defocus."

[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.

Myopia and Near Work: A Systematic Review and Meta-Analysis

BACKGROUND

Myopia is a global public health problem affecting quality of life and work productivity. Data is scarce regarding the effects of near work on myopia. Providing a larger meta-analysis with life-long perspective, including adults and occupational exposure seemed needed.

METHODS

We searched PubMed, Cochrane Library, Embase and Science Direct for studies reporting myopia prevalence in near work. Myopia was defined as a mean spherical equivalent ≤ -0.50 diopter. We performed a meta-analysis using random-effects model on myopia prevalence, myopia progression per year, and odds ratio (OR) of myopia in near work, completed by subgroup analyses and meta-regressions on patients' characteristics, type of work in adults, geographic zones, time and characteristics of near work.

RESULTS

We included 78 studies, representing a total of 254,037 participants, aged from 6 to 39 years. The global prevalence of myopia in near work was 35% (95% CI: 30 to 41%), with a prevalence of 31% (95% CI: 26 to 37%) in children and 46% (95% CI: 30 to 62%) in adults. Myopia progression was -0.39 diopters per year (-0.53 to -0.24 D/year), ranging from -0.44 (-0.57 to -0.31) in children to -0.25 D/year (-0.56 to 0.06) in adults. The odds of myopia in workers exposed vs. non-exposed to near work were increased by 26% (18 to 34%), by 31% (21 to 42%) in children and 21% (6 to 35%) in adults. Prevalence of myopia was higher in adults compared to children (Coefficient 0.15, 95% CI: 0.03 to 0.27).

CONCLUSIONS

Near work conditions, including occupational exposure in adults, could be associated with myopia. Targeted prevention should be implemented in the workplace.

Prevalence and Risk Factors of Refractive Errors and Effective Spectacle Coverage in Emiratis and Non-Emiratis Aged 40 Years or Older: the Dubai Eye Health Survey

PURPOSE

The aim was to investigate the prevalence and risk factors of refractive errors (REs) and the effective spectacle coverage in Emiratis and non-Emiratis in Dubai.

DESIGN

The Dubai Eye Health Survey was a population-based cross-sectional study of participants aged 40 years or older.

METHODS

Distance and near visual acuity (VA), and noncycloplegic automated refraction were tested according to a standardized protocol. Distance VA was tested using the Early Treatment Diabetic Retinopathy Study (ETDRS) logMAR chart at 3 m and near VA was measured using the near vision logMAR chart at 40 cm under ambient lighting. Myopia was defined as spherical equivalent of refraction of less than -0.50 diopters (D), and hypermetropia as spherical equivalent of more than +0.50 D. Astigmatism was defined as cylinder power of 0.5 D or greater. Effective spectacle coverage for distance vision was computed as met need/(met need+unmet need+under-met need)×100%. Multivariable logistic regression models were used to examine associations between sociodemographic factors and RE.

RESULTS

The authors included 892 participants (446 Emiratis and 446 non-Emiratis) in the analysis. The prevalence of hypermetropia was 20.4% [95% confidence interval (CI): 16.8%-24.4%] in Emiratis and 20.6% (95% CI: 20.0%-24.7%) in non-Emiratis. The prevalence of myopia and high myopia was 27.4% (95% CI: 23.3%-31.7%) and 1.8% (95% CI: 0.8%-3.5%) in Emiratis, and 19.5% (95% CI: 15.9%-23.5%) and 0.9% (95% CI: 0.2%-2.3%) in non-Emiratis, respectively. High education (P=0.02) and not currently working (P=0.002) were risk factors of myopia in non-Emiratis only. The prevalence of astigmatism was 7.4% (95% CI: 5.1%-10.2%) in Emiratis and 1.6% (95% CI: 0.6%-3.2%) in non-Emiratis. This prevalence was higher in individuals aged over 60 years (P<0.001) and men (P=0.014) among Emiratis. The prevalence of anisometropia and uncorrected presbyopia was 11.4% (95% CI: 8.6%-14.8%) and 0.7% (95% CI: 0.1%-2.0%) in Emiratis, and 9.2% (95% CI: 6.7%-12.3%) and 0.4% (95% CI: 0.05%-1.6%) in non-Emiratis, respectively. The effective spectacle coverage was 62.3% (95% CI: 54.0%-70.6%) and 69% (95% CI: 60.5%-77.5%) in Emiratis and non-Emiratis, respectively.

CONCLUSIONS

A high proportion of Emiratis and non-Emiratis was affected by RE without optimal effective spectacle coverage, highlighting the imperativeness of intervention to alleviate the burden. The findings may help facilitate evidence-based policymaking concerning the delivery of eye care services and allocation of medical resources in Dubai.

[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.

Five-year change in refractive error and its risk factors: results from the Gutenberg Health Study

BACKGROUND/AIMS

To examine the 5-year change in refractive error in phakic eyes and its risk factors in the general population.

METHODS

The Gutenberg Health Study (GHS) is a population-based cohort study including 15 010 participants from Germany aged 35-74 years at baseline examination (2007-2012). After 5 years, a follow-up examination was carried out (83% participation). 5-year change of spherical equivalent (SE) was computed as difference between follow-up and baseline objective refraction. Linear and logistic regression analysis were conducted analysing potential risk factors. Only phakic eyes at follow-up examination were included.

RESULTS

Right eyes of 10 175 subjects were included. An age-related shift of refractive error was identified, namely -0.12 D for age 35-44 years, 0.25 D for age 45-54 years, 0.25 D for age 55-64 years and 0.12 D for age 65-74 years during the 5-year follow-up. Smokers had a hyperopic shift (OR=1.31; p<0.001), while baseline SE (OR=0.89 per dioptre; p<0.001) and female sex (OR=1.49; p<0.001) were linked with a myopic shift. Education, occupation and other cardiovascular parameters were not associated with change in refractive error.

CONCLUSIONS

The GHS demonstrates a parabolic shift in refractive error with a myopic shift at age 35-44 years, followed by a hyperopic shift at age 45-64 years which decreases at higher age. Smoking is associated with a hyperopic shift whereas female sex and myopic baseline SE is associated with a myopic shift. Educational level and occupation were not linked to a change in refractive error at age 35-74 years.

Association between age at menarche and risk of myopia in the United States: NHANES 1999-2008

We evaluate the effect of menarche on myopia in women in the United States (US). A cross-sectional survey and examination were conducted using data from the 1999-2008 US National Health and Nutrition Examination Survey (NHANES), and 8,706 women aged ≥20 years (95% confidence interval [CI], 44.23 to 45.37) were enrolled. Characteristics were compared between nonmyopic and myopic participants. Univariable and multivariable logistic regression analysis was performed to evaluate the risk factors for myopia. A minimum p-value approach was used to estimate the cut-off point for age at menarche. The prevalence of myopia was 32.96%. Mean spherical equivalent (SE) were -0.81 diopters (95% CI, -0.89 to -0.73) and the mean age of menarche was 12.67 years (95% CI, 12.62 to 12.72). In the crude logistic regression model, age (odd ratio [OR] 0.98), height (OR, 1.02), astigmatism (OR, 1.57) (all p < 0.0001), age at menarche (OR, 0.95; p = 0.0005), white ethnicity, being born in the US, higher level of education, and higher annual household income (all p trend <0.0001) were significantly associated with myopia. 1-year increments in age at menarche was associated with a 4% decrease in the risk of myopia after adjusting for age, height, body mass index (BMI), ethnicity, and astigmatism (OR, 0.96; 95% CI, 0.93 to 0.99, p = 0.0288). The cut-off value for age at menarche was 15 years by the maximum chi-square test (p < 0.0001). Age at menarche may attribute to myopia progression, along with other environmental and individual risk factors.

Role of tutorial classes and full day schooling on self-reported age of myopia onset: findings in a sample of Argentinian adults

PURPOSE

To investigate the effect of tutorial classes and schooling schedule in childhood on age of myopia onset.

METHODS

Refractive data for subjects ≥18 years of age were collected from 8 dispensing opticians or refractive ophthalmologists' offices in Argentina. Age of myopia onset, spherical equivalent (SE), and risk factors were determined using questionnaires. Multiple linear regression models were applied to assess possible factors associated with age of myopia onset or final adult SE.

RESULTS

A total of 274 adults (61.3% females) with myopia between -0.50 and -6.00 D were included. Mean age was 36.9 ± 14.5 years. The mean adult SE was -2.95 ± 1.45 D, and the mean age of myopia onset was 14.2 ± 5.4 years. Subjects that attended after-school tutorial classes (β = -2.23; P = 0.005) or a full day schedule in primary school (β = -1.07; P = 0.035) or that spent more time on near work (β = -0.70; P = 0.010) in childhood, had younger age of myopia onset.

CONCLUSIONS

In our study cohort, adults that had attended tutorial classes and/or full-day schooling during childhood had younger age of myopia onset.

Accommodation lags are higher in myopia than in emmetropia: Measurement methods and metrics matter

Purpose

To determine whether accommodative errors in emmetropes and myopes are systematically different, and the effect of using different instruments and metrics.

Methods

Seventy‐six adults aged 18–27 years comprising 24 emmetropes (spherical equivalent refraction of the dominant eye +0.04 ± 0.03 D) and 52 myopes (−2.73 ± 0.22 D) were included. Accommodation responses were measured with a Grand Seiko WAM‐5500 and a Hartmann–Shack Complete Ophthalmic Analysis System aberrometer, using pupil plane (Zernike and Seidel refraction) and retinal image plane (neural sharpness—NS; and visual Strehl ratio for modulation transfer function—VSMTF) metrics at 40, 33 and 25 cm. Accommodation stimuli were presented to the corrected dominant eye, and responses, referenced to the corneal plane, were determined in the fellow eye. Linear mixed‐effects models were used to determine influence of the refractive group, the measurement method, accommodation stimulus, age, race, parental myopia, gender and binocular measures of heterophoria, accommodative convergence/accommodation and convergence accommodation/convergence ratios.

Results

Lags of accommodation were affected significantly by the measurement method (p < 0.001), the refractive group (p = 0.003), near heterophoria (p = 0.002) and accommodative stimulus (p < 0.05), with significant interactions between some of these variables. Overall, emmetropes had smaller lags of accommodation than myopes with respective means ± standard errors of 0.31 ± 0.08 D and 0.61 ± 0.06 D (p = 0.003). Lags were largest for the Grand Seiko and Zernike defocus, intermediate for NS and VSMTF, and least for Seidel defocus.

Conclusions

The mean lag of accommodation in emmetropes is approximately equal to the previously reported depth of focus. Myopes had larger (double) lags than emmetropes. Differences between methods and instruments could be as great as 0.50 D, and this must be considered when comparing studies and outcomes. Accommodative lag increased with the accommodation stimulus, but only for methods using a fixed small pupil diameter.

The equations of ametropia: Predicting myopia

Why myopia develops, why it is reaching epidemic proportions and what is its cause are questions that puzzle many people. There is an answer to these questions and it is a simple one. This paper makes the connection between ametropic and in particular myopic development and theory to come with a summary of what we know about myopia and its governing equation. Key experiments, involving myopia and the effect of lenses in humans and animals have been done with unmistakable results. The observed effect of lenses implies a feedback mechanism. Feedback theory explains those results with mathematical precision. Disruption of emmetropization, is the mechanism behind ametropia and particularly myopia. Feedback theory for emmetropization was derived by observation of the input and output of the emmetropization feedback system in many patients. We show that it has the same equation as it is derived here independently from simple homeostasis principles. Classical observations and recent clinical studies have shown the association of many variables with myopia. They include near work, atropine, lenses, blur and outdoors versus indoors activities. We propose that human refractive development is controlled by homeostasis and based on that alone we derive the equation for the calculation of refraction for any patient and the effect of lenses. We provide software to calculate the refraction of any individual at any time. The editor of this journal makes the following statement: "This manuscript is intended for scientific discussion rather than clinical application. The present work does not intend to promote clinical under correction or no correction of myopia. Instead, clinicians should follow current clinical myopia management guidelines."

The Evolution and the Impact of Refractive Errors on Academic Performance: A Pilot Study of Portuguese School-Aged Children

The relationship between vision and academic performance has been discussed for a long time, with special emphasis on visual factors associated with learning problems. The objective of this pilot study is to obtain an initial idea about the evolution and the impact of refractive errors on school-aged children. A visual examination was performed on 252 children between the ages of 6 and 11 years, which consisted of objective refraction, subjective refraction, and accommodative and binocular tests. No significant differences were observed regarding the refractive state when taking academic performance into account (p > 0.05). However, it was determined that academic performance was better among children with a negative spherical equivalent. Studies with a larger sample size must be conducted to verify the results that were attained in this present pilot study, and these must likewise look at possible ways in which strategies can be implemented in schools to reduce myopia progression.

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

After decades of investigation, the role of near work in myopia remains unresolved, with some studies reporting no relationship and others finding the opposite. This systematic review is intended to summarize classic and recent literature investigating near work and the onset and progression of myopia, potential mechanisms and pertinent clinical recommendations. The impact of electronic device use is considered. PubMed and Medline were used to find peer-reviewed cross-sectional and longitudinal studies related to near work and myopia from 1980 to July 2020 using the PRISMA checklist. Studies were chosen using the Joanna Briggs Institute checklist, with a focus on studies with a sample size greater than 50. Studies were independently evaluated; conclusions were drawn per these evaluations. Numerous cross-sectional studies found increased odds ratio of myopia with increased near work. While early longitudinal studies failed to find this relationship, more recent longitudinal studies have found a relationship between myopia and near work. Rather than daily duration of near work, interest has increased regarding absolute working distance and duration of continuous near viewing. Several reports have found that shorter working distances (<30 cm) and continuous near-work activity (>30 min) are risk factors for myopia onset and progression. Novel objective continuously measuring rangefinding devices have been developed to better address these questions. The literature is conflicting, likely due to the subjective and variable nature in which near work has been quantified and a paucity of longitudinal studies. We conclude that more precise objective measures of near viewing behaviour are necessary to make definitive conclusions regarding the relationship between myopia and near work. Focus should shift to utilizing objective and continuously measuring instruments to quantify near-work behaviours in children, followed longitudinally, to understand the complex factors related to near work. A better understanding of the roles of absolute working distance, temporal properties, viewing breaks and electronic device use on myopia development and progression will aid in the development of evidence-based clinical recommendations for behavioural modifications to prevent and slow myopia.

One-year analysis of the refractive stability, axial elongation and related factors in a high myopia population after Implantable Collamer Lens implantation

PURPOSE

To investigate the refractive stability, axial length (AL) changes and their related factors in a high myopia population after Implantable Collamer Lens (ICL) implantation.

METHODS

This prospective study included 116 eyes of 116 patients divided into several groups based on the spherical equivalent refractive error (SE)-SE > - 6 D, - 12 ≤ SE < - 6 D and SE < - 12 D groups-and AL-AL < 28 mm and AL ≥ 28 mm groups. The uncorrected and corrected distance visual acuity, refraction, AL and intraocular pressure were followed for 1 year.

RESULTS

SE changed from - 11.53 ± 5.25 D preoperatively to - 0.33 ± 0.70 D at 1 week, and further changed to - 0.48 ± 0.77 D at 1 year after ICL implantation, with average progression being - 0.15 ± 0.37 D from 1 week to 1 year after surgery. AL changed from 27.95 ± 2.33 mm preoperatively to 27.98 ± 2.36 mm 1 year after surgery, with an average axial elongation of 0.03 ± 0.12 mm. The mean axial elongation rate was 0.05 mm/year in the SE < - 12 D group, being significantly faster than the other refractive groups (P < 0.05); it was 0.06 mm/year in the AL ≥ 28 mm group, being significantly faster than the AL < 28 mm group (P < 0.05).

CONCLUSION

Patients with high myopia and long AL showed a continuous myopic progression and axial elongation at an adult age one year after ICL surgery, especially in those with myopia higher than - 12.00 D and AL longer than 28.00 mm.

Vision tests on spectacle lenses and contact lenses for optical myopia correction: a pilot study

Objective

Visual performance and short-term tolerability of different designs of myopia correcting options, including therapeutically relevant bifocal contact lenses (CL) and spectacle lenses with ‘defocus incorporated multiple segments (DIMS)’ technology were compared.

Methods and analysis

In myopic volunteering subjects (n=8; spherical equivalent range: −1 to −7 D) visual acuity (VA) using Landolt C and contrast sensitivity (CS) using contrast C were assessed at three different gaze positions (−22° nasal, +22° temporal and 0° central), corresponding to a gaze through the DIMS area or the clear area of the DIMS lens design, respectively, after short-term wear of each of single vision spectacle lenses (SV), DIMS spectacle lenses (DIMS), monofocal soft CL and centre-near multifocal soft CL (MCL). Also, CS was assessed under photopic and mesopic light conditions with and without glare using sinusoidal gratings at 1.5, 3, 6, 12 and 18 cpd.

Results

Mean VA (Landolt C) was −0.12 to –0.10, −0.05 and 0.10 logMAR (SV, DIMS, CL, MCL) at central gaze (0°). At nasal gaze (−22°), VA differed by 0.12, 0.33, 0.05 and 0.01, and at temporal gaze (+22°) by 0.05, 0.26, 0 and −0.08 compared with central gaze values. Mean CS (Contrast C) was 1.74, 1.73, 1.69 and 1.61 logCS (SV, DIMS, CL, MCL) at central gaze at nasal gaze, CS differed by −0.02 to –0.13, −0.01 and −0.01, and at temporal gaze by −0.02 to –0.16, −0.01 and +0.06 compared with central gaze values.

Conclusion

When compared with SV, MCL leads to a general decrease in VA and CS, while DIMS did not differ from SV at straight gaze (0° gaze). With DIMS, VA and CS are decreased to a similar level as with the MCL, but only at nasal and temporal gaze.

Relationship between peripheral refraction, axial lengths and parental myopia of young adult myopes

PURPOSE

To determine the relationship between peripheral refraction at the horizontal retina, axial length and parental history of myopia between myopic adults who have positive parental myopia and those with negative parental myopia.

METHODS

69 males and 44 females in the age range of 18-25 years were assigned either a negative parental myopia (NPM) or positive parental myopia (PPM) group. In the corrected and uncorrected states, peripheral refractive error was measured up to 30° horizontally in 10° steps using an open field autorefractor. Axial length was measured using an Opto US1000 Fine A-Scan Ultrasonography (model US1000).

RESULTS

Relative peripheral refractive error showed more hyperopic defocus that was statistically significantly more increased in the positive parental myopia group than in the negative parental myopia group (P ≥ 0.02). The overall mean ± SD axial length of all subjects was 23.38 ± 0.32 mm (range 23.01-25.01 mm). The study showed a statistically significant difference (P = 0.005) in axial lengths of young adult myopes (23.45 ± 0.36 mm) with parental myopia compared to those with similar spherical equivalent refraction who have non-myopic parents (23.28 ± 0.19 mm).

CONCLUSION

There was significantly more hyperopic defocus at 30° N and 30° T retina in the corrected states of young adult myopes who had myopic parents compared to their counterparts with non-myopic parents.

Association of School Education With Eyesight Among Children and Adolescents

IMPORTANCE

Myopia in youths is an increasingly common global problem, associated with significant social and economic burden worldwide.

OBJECTIVES

To explore the association of school education with myopia and investigate its scale, controlling confounding factors, such as age and socioeconomic status.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study was conducted from July 2019 to December 2020 using regression discontinuity (RD) based on the Compulsory Education Law to examine the complex association of school education with myopia. Participants were youths from grades 1 to 12 before tertiary or university studies in China, including individuals from 815 primary schools, 373 junior high schools, and 145 senior high schools. Data were analyzed from February through June 2021.

EXPOSURES

Participants born earlier in a year (ie, January to August) were assigned 1 more year of education and were considered to be in the treated group, while participants born September to December were considered to be in the control group.

MAIN OUTCOMES AND MEASURES

Differences in mean spherical equivalent refractive error (MSE) and uncorrected visual acuity (UVA) between treated and control groups were calculated.

RESULTS

Among a mean (SD) of 812 979 (55 953) participants across 5 surveys survey (mean SD 44.9% [0.5%] female participants; mean [SD] age, 11.19 [2.60] years), the mean (SD) MSE was -1.30 (2.93) diopters and mean (SD) UVA was 4.77 (0.34) points. Every additional year at school was associated with an decrease in MSE of -0.17 diopters/y (95% CI, -0.22 to -0.11 diopters/y) and a decrease in UVA of -0.03 points/y (95% CI, -0.04 to -0.02 points/y), which accounts for nearly 66.4% (95% CI, 85.9% to 43.0%) and 78.9% (95% CI, 102.6% to 55.3%) of changes of MSE and UVA, respectively, among all factors for youths. The greatest MSE shifts occurred in grades 3 and 7 (eg, for the June 2019 census, the RD was -0.26 diopters/y [95% CI, -0.33 to -0.20 diopters/y] for grade 3 and -0.41 diopters/y [95% CI, -0.66 to -0.15 diopters/y] for grade 7).

CONCLUSIONS AND RELEVANCE

These findings suggest that receiving more years of education, instead of age, may be a risk factor associated with myopia progression in youths.

Genome-wide Association Study of Axial Length in Population-based Cohorts in Japan

Purpose

To elucidate the differences in ocular biometric parameters by generation and gender and to identify axial length (AL)-associated genetic variants in Japanese individuals, we analyzed Tohoku Medical Megabank Organization (ToMMo) Eye Study data.

Design

We designed the ToMMo Eye Study, examined AL variations, and conducted genome-wide association studies (GWASs).

Participants

In total, 33 483 participants aged > 18 years who were recruited into the community-based cohort (CommCohort) and the birth and three-generation cohort (BirThree Cohort) of the ToMMo Eye Study were examined.

Methods

Each participant was screened with an interview, ophthalmic examinations, and a microarray analysis. The GWASs were performed in 22 379 participants in the CommCohort (discovery stage) and 11 104 participants in the BirThree Cohort (replication stage). We evaluated the associations of single nucleotide polymorphisms (SNPs) with AL using a genome-wide significance threshold (5 × 10^-8) in each stage of the study and in the subsequent meta-analysis.

Main Outcome Measures

We identified the association of SNPs with AL and distributions of AL in right and left eyes and individuals of different sexes and ages.

Results

In the discovery stage, the mean AL of the right eye (23.99 mm) was significantly greater than that of the left eye (23.95 mm). This difference was reproducible across sexes and ages. The GWASs revealed 703 and 215 AL-associated SNPs with genome-wide significance in the discovery and validation stages, respectively, and many of the SNPs in the discovery stage were replicated in the validation stage. Validated SNPs and their associated loci were meta-analyzed for statistical significance (P < 5 × 10^-8). This study identified 1478 SNPs spread over 31 loci. Of the 31 loci, 5 are known AL loci, 15 are known refractive-error loci, 4 are known corneal-curvature loci, and 7 loci are newly identified loci that are not known to be associated with AL. Of note, some of them shared functional relationships with previously identified loci.

Conclusions

Our large-scale GWASs exploiting ToMMo Eye Study data identified 31 loci linked to variations in AL, 7 of which are newly reported in this article. The results revealed genetic heterogeneity and similarity in SNPs related to ethnic variations in AL.

Temporal trends in frequency, type and severity of myopia and associations with key environmental risk factors in the UK: Findings from the UK Biobank Study

This study investigated temporal trends in the epidemiology of primary myopia and associations with key environmental risk factors in a UK population. Data were collected at recruitment (non-cycloplegic autorefraction, year of birth, sex, ethnicity, highest educational attainment, reason and age of first wearing glasses and history of eye disease) from 107,442 UK Biobank study participants aged 40 to 69 years, born between 1939 and 1970. Myopia was defined as mean spherical equivalent (MSE) ≤-1 dioptre (D). Temporal changes in myopia frequency by birth cohort (5-year bands using date of birth) and associations with environmental factors were analysed, distinguishing both type (childhood-onset, <18 years versus adult-onset) and severity (three categories: low -1.00 to -2.99D, moderate -3.00 to -5.99D or high ≥-6.00D). Overall myopia frequency increased from 20.0% in the oldest cohort (births 1939–1944) to 29.2% in the youngest (1965–1970), reflecting a relatively higher increase in frequency of adult-onset and low myopia. Childhood-onset myopia peaked in participants born in 1950–54, adult-onset myopia peaked in the cohort born a decade later. The distribution of MSE only shifted for childhood-onset myopia (median: -3.8 [IQR -2.4, -5.4] to -4.4 [IQR -3.0, -6.2]). The magnitude of the association between higher educational attainment (proxy for educational intensity) and myopia overall increased over time (adjusted Odds Ratio (OR) 2.7 [2.5, 2.9] in the oldest versus 4.2 [3.3, 5.2] in the youngest cohort), being substantially greater for childhood-onset myopia (OR 3.3 [2.8, 4.0] to 8.0 [4.2, 13]). Without delineating childhood-onset from adult-onset myopia, important temporal trends would have been obscured. The differential impact of educational experience/intensity on both childhood-onset and high myopia, amplified over time, suggests a cohort effect in gene-environment interaction with potential for increasing myopia frequency if increasing childhood educational intensity is unchecked. However, historical plateauing of myopia frequency does suggest some potential for effective intervention.

Prevalence of myopia and high myopia, and the association with education: Shanghai Child and Adolescent Large-scale Eye Study (SCALE): a cross-sectional study

OBJECTIVES

To report on: (a) overall myopia and high myopia prevalence, and (b) the impact of education on the spherical equivalent refractive error in children across Shanghai.

DESIGN

Cross-sectional study.

SETTING

Across all 17 districts of Shanghai.

PARTICIPANTS

910 245 children aged 4-14 years from a school-based survey conducted between 2012 and 2013.

MAIN OUTCOME MEASURES

Data of children with non-cycloplegic autorefraction, visual acuity assessment and questionnaire were analysed (67%, n=6 06 476). Prevalence of myopia (≤-1.0 D) and high myopia (≤-5.0 D) was determined. We used a regression discontinuity design to determine the impact of school entry cut-off date (1 September) by comparing refractive errors at each age, for children born pre-September to post-1 September, and performed a multivariate analysis to explore risk factors associated with myopia. Data analysis was performed in 2017-2018.

RESULTS

Prevalence rates of myopia and high myopia were 32.9% (95% CI: 32.8% to 33.1%) and 4.2% (95% CI: 4.1% to 4.2%), respectively. From 6 years of age onwards, children born pre-September were more myopic compared with those born post-1 September (ahead in school by 1 year, discontinuity at 6 years: -0.19 D (95% CI: -0.09 to -0.30 D); 14 years: -0.67 D (95% CI: -0.21 to -1.14 D)).

CONCLUSIONS

Our findings suggest that myopia is associated with education, that is primarily focused on near-based activities. Efforts to reduce the burden should be directed to public awareness, reform of education and health systems.

Attitude toward refractive error surgery and other correction methods: A cross-sectional study

Background

Refractive errors are the most common vision problem and prove to be a significant health issue. There are several methods for correction of refractive errors including spectacles, contact lenses and refractive surgery. Nowadays, the reliance on contact lenses and glasses is decreased by means of refractive eye surgery. Our study aimed to determine the awareness of refractive surgery among undergraduate medical students and their preferred method of refractive error correction.

Method

This was a cross-sectional study that was conducted among a sample size of 374 medical students at King Abdul-Aziz University Hospital, Jeddah, Saudi Arabia in June–August 2020. Data were collected through a questionnaire which consisted of 20 questions to assess the demographics, awareness about refractive surgery and preferred method of correction. The data were entered using Microsoft Excel 2016 and analyzed by SPSS version 21.

Results

Our results showed that 177 of participants had refractive errors. Most participants complained of myopia (66.7%) and the most preferred correction method was spectacles (45.8%). Among users of spectacles, 53.7% found the spectacles comfortable due to ease of use. Majority of the students (92.1%) were aware of refractive surgery and 73% of them were willing to undergo refractive surgery. Many obtained their information regarding these procedures from family and friends (55.1%). The remaining refused to undergo surgery and the primary reason was fear of the complications of the procedure (14.1%).

Conclusion

Though corrective refractive surgery is a commonly performed procedure, extensive knowledge regarding this correction method and its complications is poor among medical students. The results showed that the majority have heard of refractive surgery, however, fear of undergoing surgery was still present. We suggest that refractive error correction surgery be taught by physicians during Ophthalmology rotations so that knowledge may be gained from more reliable sources.

-

Though corrective refractive surgery is a commonly performed procedure, proper knowledge regarding this correction method is poor among medical students.

-

Spectacles were the most common correction method used, followed by both spectacles and contact lenses.

-

The results of our study demonstrate that most students are aware of refractive surgery but there is still a moderate willingness to undergo refractive surgery mostly due to fear of complications.

-

Most of the participants reported that family and friends were their main source of knowledge.

-

We recommend refractive surgical correction methods be introduced by physicians in Ophthalmology rotations during medical school and provide students with more information about the safety and efficacy of these surgeries.

Refractive errors and risk factors for myopia in infants aged 1-18 months in Tianjin, China

BACKGROUND

Infancy is the of a child's visual development. Refractive errors, especially myopia, are a common vision disorder. Thus, the purpose of this study was to explore refractive errors and risk factors for myopia among infants aged 1-18 months in Tianjin, China.

METHODS

A total of 583 infants aged 1-18 months participated in this cross-sectional study at Tianjin Women's and Children's Health Center in China from February 2019 to November 2020. Each infant received a complete ophthalmologic examination, and myopia-related risk factors were investigated using a questionnaire.

RESULTS

A total of 583 eligible infants participated in this study, including 312 (53.5%) boys and 271 (46.5%) girls. There were 164 (28.1%) premature born infants. The mean age was 6.59 ± 4.84 months (range, 1-18 months). The mean spherical equivalent (MSE) for the right eye was 1.81 D ± 1.56 D, with no difference related to sex (P = 0.104). Refractive state showed an average hyperopia of +2.74 ± 1.74 D at early ages, followed by a trend toward less hyperopia, finally reaching +1.35 ± 1.44 D at the age of 18 months (P ≤0.001). The overall prevalence rates of myopia (MSE ≤ -0.50 D), emmetropia (-0.50 D<MSE<+0.50 D), hyperopia (MSE ≥ +2.00 D), and astigmatism (≥ 1.50 D) were 5.1%, 10.8%, 42.7%, and 49.9%, respectively. The chi-square tests showed that gender, gestational age ≥37 weeks, winter birth, prenatal exposure to environmental tobacco smoke, and parental history of high myopia were associated with children's myopia (P = 0.022, P = 0.023, P = 0.038, P = 0.015, P<0.001, respectively).

CONCLUSIONS

Among Chinese infants in Tianjin, hyperopia and astigmatism were the most frequent refractive errors, and the diopter was lower in individuals with higher age. In a small number of infants with myopia, genetic factors and the prenatal environment were associated with the early onset of myopia.

Myopia progression and axial elongation in Spanish children: Efficacy of atropine 0.01% eye-drops

PURPOSE

To assess myopia progression in Spanish children and whether treatment with low-dose atropine eye drops delays myopia progression and axial elongation.

MATERIALS AND METHODS

METHODS

339 eyes of 339 Caucasian patients with myopia, aged 5 to 11 years, were examined. Participants were randomized to a treatment arm, receiving one atropine (0.01%) eye drop/day for two, and an untreated control arm. At the baseline and 2-year follow-up visits, we recorded: spherical equivalent (SE), axial length (AL), mean keratometry (Mean-K) and anterior chamber depth (ACD). We also examined the rate of children with higher myopia progression (change in SE >1 D/2 years) and identified risk factors for progression.

RESULTS

In 339 eyes of the 339 children (age=7.61; SD 1.70; range 5-11 years), the mean baseline SE was-2.15 (SD 0.62) D, and AL was 24.24 (SD 0.79) mm. After 2 years, higher increases occurred in all variables except ACD in the untreated group vs. the atropine group, respectively: SE (-0.51 (SD 0.39) D vs. -0.76 (SD 0.37) D, P<0.001), AL (0.20 (SD 0.20) mm vs. 0.37 (SD 0.27) mm, P<0.001) and Mean-K (0.01 (0.28) D vs. 0.09 (0.32) D, P=0.018). Myopia progression was reduced by 32% in the treatment group. There were more progressors >1D/2y in the control group: 62/168 (36.9%) vs. 35/171 (20.5%) (P<0.001). Atropine was identified as a protective factor against myopia progression (B=1.12; 95% CI= 0.98-1.27; P=<0.001).

CONCLUSION

Spanish children showed a low rate of myopia progression. Atropine 0.01% showed a significant effect in slowing the progression of both refractive error and axial elongation.

Is myopia prevalence related to outdoor green space?

PURPOSE

Rapid urbanisation and lifestyle changes have been associated with a huge increase in myopia across many parts of the world. There is strong evidence that environmental factors including time outdoors and urbanisation can influence the development of myopia, particularly in school-aged children. The aim of this study is to determine whether there is a relationship between the prevalence of myopia and the amount of vegetation/green spaces across different regions of the world, as a risk factor for myopia development.

METHODS

The prevalence of myopia in the 15 to 19-year age group in Australia, Brazil, China, Finland, India, Iran, Japan, Oman, Singapore, South Africa and the UK was obtained from a meta-analysis by Holden et al. Normalised Difference Vegetation Index (NDVI) was used to quantify green space exposure based on Landsat 7 Enhanced Thematic Mapper Plus (ETM+) satellite data. Green space was measured in locations specific to 15 studies that reported myopia prevalence. Simple linear regression was used to analyse yearly data, and a mixed effects model was applied to assess the significance of green space when study was a random effect.

RESULTS

Myopia prevalence increases significantly when green space was <-0.2, but the effect was less apparent for values >-0.1. When a mixed effects model was used, the effect of green space was found to be significantly associated with myopia prevalence (p = 0.05).

CONCLUSIONS

There was evidence of a weak but significant non-linear relationship between myopia and green space, with the effect most apparent at low levels of green space. A larger data sample, along with further investigations into the utilisation of green spaces, are required to understand whether increasing the amount of green space can reduce myopia incidence and progression impact.

Impact of the Pressure-Free Yutori Education Program on Myopia in Japan

This study aimed to investigate the influence of educational pressure on myopia. A less-intense school curriculum was introduced nationally in Japan beginning in 2012 based on a pressure-free education policy. In this retrospective observational study, a total of 1025 Japanese medical students of Asahikawa Medical University underwent measurements of the cycloplegic refractive error and axial length (AL), from 2011 to 2020. The spherical equivalent (SE) and AL were correlated significantly with the fiscal year of births (p = 0.004 and p = 0.034, respectively) only during enforcement of the system of high-pressure education. The SE and AL regression rates during the two educational approaches differed significantly (p = 0.004 and p = 0.037, respectively). The prevalence of high myopia was correlated significantly (p < 0.001) only during the system of high-pressure education. The regression of the prevalence rate of high myopia during the two education approaches differed significantly (p = 0.010). The progression rates of myopia and increased prevalence of high myopia were observed only during high-pressure education, suggesting that not only ophthalmologists but also educators and the government should work on together to control the progression of myopia.

Effect of Sunshine Duration on Myopia in Primary School Students from Northern and Southern China

Background

To assess the current myopia prevalence rate and evaluate the effect of sunshine duration on myopia among primary school students in the north and south of China.

Methods

This prospective cross-sectional study pooled data from 9171 primary school students (grades from 1 to 6) from four cities in the north and south of China. National Geomatics Center of China (NGCC) and China Meteorological Administration provided data about altitude, latitude, longitude, average annual temperature, and average annual sunshine duration. Non-cycloplegic refraction was recorded, and prevalence rates in primary school students and factors associated with myopia were analyzed. Univariate and multivariate logistic regression models were used to determine the independent association of risk factors of myopia.

Results

The overall myopia prevalence was 28.0%, from 7.5% to 50.6% for first and sixth grades, respectively. Low, moderate and high myopia significantly increased with school grades from 7.30% to 35.0%, 0.3% to 13.60% and 0.00% to 1.9%, respectively. Multiple regression analysis revealed that longer average cumulative daylight hours were connected to lower myopia prevalence in primary school students (OR, 0.721; 95% CI, [0.593–0.877]; P=0.001), whereas girls and higher grade was independently associated with higher myopia prevalence (girls: β=0.189; OR, 1.208; 95% CI, [1.052–1.387]; P=0.007; higher grade: β=0.502; OR, 1.652; 95% CI, [1.580–1.726]; P<0.001).

Conclusion

This study demonstrated that myopia was highly prevalent in southern Chinese cities over northern ones, linked to shorter light exposure, higher education level, and female gender. Such findings reinforced the beneficial impact of daylight exposure with a protective role against myopia development.

The cause of myopia development and progression: Theory, evidence, and treatment

I review the key findings and our current knowledge of the cause of myopia, making the connections among the reliable observations on myopia development and theory to arrive at a summary of what we know about myopia, the proposed prevailing theory, and applicable action. Myopia is reaching epidemic proportions. It is estimated that half of the world's population will be myopic by 2050 unless new strategies to fight myopia are developed. Our high-level mathematical description of myopia is translated into clinical applications involving effective treatment and prevention. A regulating mechanism controlling the refraction of the eye is intimately related to myopia. The approach at hand is to review our knowledge about emmetropization, connecting myopia and emmetropization feedback theory to unveil the cause of myopia. Many observations discussed here test the validity of feedback theory positively. The cause of human myopia fits perfectly with the idea that emmetropization, in particular its feedback theory implementation, is the controlling mechanism behind myopia. They include near work, atropine, lenses, defocus, and outdoor versus indoor activities. The key findings in myopia research point the same way: myopia is the result of corrective lenses interfering with emmetropization. We have enough knowledge to answer the question of whether myopia can be reversed or prevented. There is no need to have mathematical skills to apply theory to real cases. It is enough to know the predictions of the feedback theory of emmetropization.

Early Age of the First Myopic Spectacle Prescription, as an Indicator of Early Onset of Myopia, Is a Risk Factor for High Myopia in Adulthood

Purpose

The present study investigated the risk factors for high myopia in adulthood, with a focus on the age at which children wore their first spectacles.

Methods

Adults aged between 20 and 45 years were invited to complete a questionnaire about age, sex, current refractive error, high myopia in parents, early onset of myopia presented by the age of the first myopic spectacle prescription, refractive power of the first spectacles, and life habits at different educational stages. The associations between these factors and high myopia in adulthood were then evaluated and analyzed.

Results

In total, 331 participants were enrolled. Their average refractive error was −4.03 diopters, and high myopia was noted in 27.5% of the study participants. Only 3.3% of participants had fathers with high myopia, while 6.0% had mothers with high myopia. The participants received their first myopic spectacle prescription at a mean age of 13.35 years, with a mean refractive error of −1.63 diopters. The significant risk factors for developing high myopia in adult life were earlier age of the first spectacles prescribed (p < 0.001), higher refractive power of the first spectacles (p < 0.001), mother with high myopia (p=0.015), and after-school class attendance in senior high school (p=0.018). Those who wore their first spectacles at <9 years of age were more predisposed to high myopia than those who did so at ≧13 years, with an odds ratio of 24.9.

Conclusion

The present study shows that earlier onset of myopia, which is presented by the age of the first myopic spectacle prescription, higher myopic refraction of the first spectacles, mothers with high myopia, and after-school class attendance in senior high school are risk factors for high myopia in adulthood. It suggests that delaying the onset of myopia in children is important for the prevention of high myopia in later life.

Socioeconomic mechanisms of myopia boom in China: a nationwide cross-sectional study

OBJECTIVES

To assess the association between socioeconomic development and the myopia boom in China.

DESIGN

Nationwide cross-sectional study.

SETTING

We used data from the China Family Panel Study (CFPS 2010), and the Chinese National Survey on Students' Constitution and Health (CNSSCH 2010).

PARTICIPANTS

Participants included 33 600 individuals and 14 226 families from the CFPS 2010, and 86 199 students aged 7-12 years from the CNSSCH 2010.

MEASURES

The main measure was students' visual impairment (defined as Snellen visual acuity ≤20/25 (0.8) in the worse eye) rate of each province (or municipality or autonomous region); other measures included the Gini coefficient of property, logarithm of average property, Gini coefficient of education, average education duration and return-to-education rate of each province (or municipality or autonomous region). The visual impairment rate was calculated using students' data, aged 7-12 years, from the CNSSCH 2010. The Gini coefficient of property and logarithm of average property were calculated using the families' data from the CFPS 2010; the Gini coefficient of education, average education duration and return-to-education rate were calculated using individuals' data aged 18-44 years from the CFPS 2010.

RESULTS

The urban environment (coefficient: 0.209; p<0.001), Gini coefficient of property (coefficient: 1.979; p=0.005), logarithm of average property (coefficient: 0.114; p<0.001), average education duration (coefficient: 0.041; p<0.001) and return-to-education rate (coefficient: 0.195; p<0.001) were positively associated with the logit function of visual impairment rate.

CONCLUSIONS

Economic development may promote an increased desire to pursue wealth. Regarding high return to education and a fairly competitive education system, individuals are likely to pursue wealth through education, which is associated with a heavier education burden and higher prevalence rates of myopia.

Design and Pilot data of the high myopia registration study: Shanghai Child and Adolescent Large-scale Eye Study (SCALE-HM)

PURPOSE

To describe the methodology and pilot data of the Shanghai Child and Adolescent Large-scale Eye Study (SCALE-HM).

METHODS

This is a population-based, prospective, examiner-masked study with annual follow-up. Patients are 4- to 18-year-olds with high myopia. The participants will fill out questionnaires and then undergo visual acuity, axial length (AL), intraocular pressure, ophthalmologist assessment, microperimetry, cycloplegic refraction, Pentacam, wavefront aberration, fundus, blood and saliva examinations. To describe the pilot data, intergroup differences were assessed with t-tests or analysis of variance and a logistic regression model was used to determine the independent factors associated with peripapillary atrophy (PPA).

RESULTS

Overall, 134 eyes of 79 participants met the pilot study recruitment criteria. The mean AL and spherical equivalent were 26.91 ± 1.07 mm and -9.40 ± 1.77 D, respectively. Peripapillary atrophy (PPA) (N = 112) and tessellated fundus (N = 67) were the most common fundus changes. The mean AL was significantly longer in PPA (27.08 ± 0.93 mm) than in non-PPA eyes (26.06 ± 1.31 mm; p < 0.001). Axial length (AL) (p = 0.041) was the only independent factor associated with PPA. Axial length (AL) was significantly longer in eyes with diffuse chorioretinal atrophy (N = 11; 28.02 ± 1.31 mm) than without myopic retinal lesions (N = 56; 26.48 ± 0.91 mm, p < 0.001) or with tessellated fundus (N = 67; 27.09 ± 0.97 mm, p = 0.012). The myopic degree was higher in eyes with diffuse chorioretinal atrophy than without myopic retinal lesions (-10.51 ± 2.76 D versus -9.06 ± 1.58 D, p = 0.039).

CONCLUSION

Peripapillary atrophy and tessellated fundus were common in children and adolescents with high myopia. Results from this prospective study will help to understand the mechanisms, development and prognosis of these changes and can guide early myopia screening.

Update and guidance on management of myopia. European Society of Ophthalmology in cooperation with International Myopia Institute

The prevalence of myopia is increasing extensively worldwide. The number of people with myopia in 2020 is predicted to be 2.6 billion globally, which is expected to rise up to 4.9 billion by 2050, unless preventive actions and interventions are taken. The number of individuals with high myopia is also increasing substantially and pathological myopia is predicted to become the most common cause of irreversible vision impairment and blindness worldwide and also in Europe. These prevalence estimates indicate the importance of reducing the burden of myopia by means of myopia control interventions to prevent myopia onset and to slow down myopia progression. Due to the urgency of the situation, the European Society of Ophthalmology decided to publish this update of the current information and guidance on management of myopia. The pathogenesis and genetics of myopia are also summarized and epidemiology, risk factors, preventive and treatment options are discussed in details.

IMI Risk Factors for Myopia

Risk factor analysis provides an important basis for developing interventions for any condition. In the case of myopia, evidence for a large number of risk factors has been presented, but they have not been systematically tested for confounding. To be useful for designing preventive interventions, risk factor analysis ideally needs to be carried through to demonstration of a causal connection, with a defined mechanism. Statistical analysis is often complicated by covariation of variables, and demonstration of a causal relationship between a factor and myopia using Mendelian randomization or in a randomized clinical trial should be aimed for. When strict analysis of this kind is applied, associations between various measures of educational pressure and myopia are consistently observed. However, associations between more nearwork and more myopia are generally weak and inconsistent, but have been supported by meta-analysis. Associations between time outdoors and less myopia are stronger and more consistently observed, including by meta-analysis. Measurement of nearwork and time outdoors has traditionally been performed with questionnaires, but is increasingly being pursued with wearable objective devices. A causal link between increased years of education and more myopia has been confirmed by Mendelian randomization, whereas the protective effect of increased time outdoors from the development of myopia has been confirmed in randomized clinical trials. Other proposed risk factors need to be tested to see if they modulate these variables. The evidence linking increased screen time to myopia is weak and inconsistent, although limitations on screen time are increasingly under consideration as interventions to control the epidemic of myopia.

Association of polymorphisms in ZFHX1B, KCNQ5 and GJD2 with myopia progression and polygenic risk prediction in children

AIMS

To assess the association of single-nucleotide polymorphisms (SNPs) with myopia progression for polygenic risk prediction in children.

METHODS

Six SNPs (ZC3H11B rs4373767, ZFHX1B rs13382811, KCNQ5 rs7744813, MET rs2073560, SNTB1 rs7839488 and GJD2 rs524952) were analysed in 1043 school children, who completed 3-year follow-up, using TaqMan genotyping assays. SNP associations with progression in spherical equivalent (SE) were analysed by logistic regression. Polygenic risk scores (PRS) were applied for computing the sum of the risk alleles of multiple SNPs corresponding to myopia progression, weighted by the effect sizes of corresponding SNPs.

RESULTS

GJD2 rs524952 showed significant association with fast progression (OR=1.32, 95% CI 1.10 to 1.59; p=0.003) and KCNQ5 rs7744813 had nominal association (OR=1.32, 95% CI 1.04 to 1.67; p=0.02). In quantitative traits locus analysis, GJD2 rs524952 and KCNQ5 rs7744813 were associated with progression in SE (β=-0.038 D/year, p=0.008 and β=-0.042 D/year, p=0.02) and axial elongation (β=0.016 mm/year, p=0.01 and β=0.017 mm/year, p=0.027). ZFHX1B rs13382811 also showed nominal association with faster progression in SE (β=-0.041 D/year, p=0.02). PRS analysis showed that children with the highest PRS defined by rs13382811, rs7744813 and rs524952 had a 2.26-fold of increased risk of fast myopia progression (p=4.61×10^-5). PRS was also significantly associated with SE progression (R²=1.6%, p=3.15×10^-5) and axial elongation (R²=1.2%, p=2.6×10^-4).

CONCLUSIONS

In this study, multi-tiered evidence suggested SNPs in ZFHX1B, KCNQ5 and GJD2 as risk factors for myopia progression in children. Additional attention and appropriate interventions should be given for myopic children with high-risk PRS as defined by GJD2 rs524952, KCNQ5 rs7744813 and ZFHX1B rs13382811.

Prevalence and Time Trends in Myopia Among Children and Adolescents

BACKGROUND

Myopia (near-sightedness) is increasing worldwide, especially in Asia. The aim of this study was to describe trends in the prevalence of myopia in Germany.

METHODS

We analyzed data from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS; baseline survey 2003-2006, N = 17 640; wave 2, 2014-2017, N = 15 023). The presence of myopia was determined from a parent questionnaire and validated by the use of a visual aid. The population prevalence of myopia was calculated. Based on the KiGGS wave 2 data, potential risk factors for myopia were identified by means of logistic regression.

RESULTS

The prevalence of myopia at the age of 0-17 years in Germany was 11.6% (95% confidence interval [11.0; 12.2]) in the period 2003-2006 and 11.4% [10.7; 12.2] in 2014-2017. No age group of either sex exhibited a relevant, statistically significant change in the prevalence of myopia. In the adjusted model (adjusted for age, sex, family socioeconomic status, family history of migration), no association was found between myopia and use of digital media. More time spent reading books was associated with myopia: reading for more than 2 h/day showed an odds ratio of 1.69 [1.3; 2.2].

CONCLUSION

The prevalence of myopia in children and adolescents in Germany has remained virtually unchanged over a period of approximately 10 years. Changes in media consumption, such as the increased use of smartphones in this age group, have therefore had no detectable impact on the development of myopia, at least not so far. Future studies should investigate the influences of further increases in media use and examine the long-term effects.

Open schools! Weighing the effects of viruses and lockdowns on children

This review weighs the risk of infection with SARS-CoV-2 against the side effects of school closures on physical and mental health, education, and well-being of those affected by the school closures. Whereas short term effects - decreased learning and food security, and increased anxiety, violence against children, child labor and teen pregnancies - are frequently discussed, the long-term effects of school closures will be much more detrimental across the lifespan of the "Generation Corona": Existing pandemics of inactivity and myopia, already affecting billions of people, are worsening due to less physical exercise and less time spent outdoors, poor diet, weight gain, and increased screen time during lockdowns, causing future increases of stroke, heart attack, cancer, and blindness. Socio-emotional complications of isolation, learned helplessness, economic and existential insecurity will include increased depression and suicide, decreased empathy and increased loneliness. Together with decreased educational attainment and economic productivity, the amount of ensuing increased future global morbidity and mortality justifies immediate action of school reopening.

Corneal Penetration of Low-Dose Atropine Eye Drops

Major studies demonstrating the inhibition of myopia in children and juveniles by low-dose atropine eye drops provide little information on the manufacturing process and the exact composition of the atropine dilutions. However, corneal penetration might significantly vary depending on preservatives, such as benzalkonium chloride (BAC), and the atropine concentration. Since there is a trade-off between side effects, stability, and optimal effects of atropine on myopia, it is important to gain better knowledge about intraocular atropine concentrations. We performed an ex vivo study to determine corneal penetration for different formulations. Atropine drops (0.01%) of different formulations were obtained from pharmacies and applied to the cornea of freshly enucleated pig eyes. After 10 min, a sample of aqueous humor was taken and atropine concentrations were determined after liquid–liquid extraction followed by high-performance liquid chromatography–tandem mass spectrometry (LC-MS/MS). The variability that originated from variations in applied drop size exceeded the differences between preserved and preservative-free formulations. The atropine concentration in the anterior chamber measured after 10 min was only 3.8 × 10⁻⁸ of its concentration in the applied eye drops, corresponding to 502.4 pM. Obviously, the preservative did not facilitate corneal penetration, at least ex vivo. In the aqueous humor of children’s eyes, similar concentrations, including higher variability, may be expected in the lower therapeutic window of pharmacodynamic action.

Prevalence and risk factors of myopic maculopathy: a cross-sectional study in Han and Uygur adults in Xinjiang, China

OBJECTIVES

To estimate the prevalence, ethnic differences and associated risk factors of myopic maculopathy in Han and Uygur adults in Xinjiang, China.

DESIGN AND SETTING

A cross-sectional study with multistage, stratified cluster sampling method was conducted in Xinjiang, China.

PARTICIPANTS

A total of 4023 Han and Uygur participants aged 40 years and older were eligible for the study.

OUTCOME MEASURES

The association between myopic maculopathy and its risk factors was screened using the generalised estimating equation (GEE) model. We also investigated whether ethnic differences exist between Han and Uygur populations affected by myopic maculopathy. Myopic maculopathy was defined in accordance with International Photographic Classification and Grading System for Myopic Maculopathy.

RESULTS

A total of 3044 subjects (5946 eyes) were included in our study (1736 Han and 1308 Uygur individuals). The participants consisted of 1256 (41.3%) men and 1788 (58.7%) women. The average age was 52.2±9.4 years, and the mean spherical equivalent (SE) was -0.18±2.31 dioptre (D). Myopic maculopathy was detected in 198 eyes of 138 participants. The age-adjusted prevalence of myopic maculopathy reached 5.8% (95% CI 4.8 to 6.8). In the GEE model, myopic maculopathy was significantly associated with old age (per year; OR: 1.16; 95% CI 1.13 to 1.19; p<0.001) and myopic SE (per -1 D; OR: 1.48; 95% CI 1.40 to 1.56; p<0.001). No ethnic differences were detected between Han (98, 5.7%) and Uygur population (40, 3.1%) in terms of the prevalence of myopic maculopathy (OR=0.89; 95% CI 0.53 to 1.48; p=0.64). Neither urbanisation (p=0.38) nor the level of education (p=0.92) was associated with myopic maculopathy.

CONCLUSIONS

A high age-adjusted prevalence of myopic maculopathy was observed in Han and Uygur populations in Xinjiang, China. Old age and high degree of myopic refraction were independent risk factors for myopic maculopathy. No ethnic differences were detected in Han and Uygur populations affected by myopic maculopathy.