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.

Early Alterations in Inner-Retina Neural and Glial Saturated Responses in Lens-Induced Myopia

Purpose

Myopic marmosets are known to exhibit significant inner retinal thinning compared to age-matched controls. The purpose of this study was to assess inner retinal activity in marmosets with lens-induced myopia compared to age-matched controls and evaluate its relationship with induced changes in refractive state and eye growth.

Methods

Cycloplegic refractive error (Rx), vitreous chamber depth (VCD), and photopic full-field electroretinogram were measured in 14 marmosets treated binocularly with negative contact lenses compared to 9 untreated controls at different stages throughout the experimental period (from 74 to 369 days of age). The implicit times of the a-, b-, d-, and photopic negative response (PhNR) waves, as well as the saturated amplitude (Vmax), semi-saturation constant (K), and slope (n) estimated from intensity-response functions fitted with Naka-Rushton equations were analyzed.

Results

Compared to controls, treated marmosets exhibited attenuated b-, d-, and PhNR waves Vmax amplitudes 7 to 14 days into treatment before compensatory changes in refraction and eye growth occurred. At later time points, when treated marmosets had developed axial myopia, the amplitudes and implicit times of the b-, d-, and PhNR waves were similar between groups. In controls, the PhNR wave saturated amplitude increased as the b + d-wave Vmax increased. This trend was absent in treated marmosets.

Conclusions

Marmosets induced with negative defocus exhibit early alterations in inner retinal saturated amplitudes compared to controls, prior to the development of compensatory myopia. These early ERG changes are independent of refraction and eye size and may reflect early changes in bipolar, ganglion, amacrine, or glial cell physiology prior to myopia development.

Translational Relevance

The early changes in retinal function identified in the negative lens-treated marmosets may serve as clinical biomarkers to help identify children at risk of developing myopia.

Retinal complications post posterior chamber phakic intraocular lens implantation at a tertiary eye hospital in the Eastern Province of Saudi Arabia

PURPOSE

Phakic intraocular lenses treat higher degrees of myopia not possible previously with conventional refractive surgery. The aim of this study is to report the incidence and risk factors of retinal complications after posterior chamber PIOL implantation and assess the differences in biometric parameters between patients who developed such complications versus those who did not.

METHODS

This retrospective study recruited 514 patients who underwent ICL implantation to correct myopia at a tertiary eye hospital center in the Eastern province of Saudi Arabia. Follow up period was at least one year. Medical records of the patients were reviewed to obtain the required data. Associations between respondents' characteristics and retinal complications were evaluated using the Chi-squared test.

RESULTS

The mean (SD) age was 27.7 (± 6.5) years ranging from 18 to 47. Laser treatment was performed in 14 cases (2.7%). Retinal complications occurred in six cases (1.2%). The risk of retinal complication was significantly higher among patients with high axial length (OR = 1.3, 95% CI 1.2, 1.4) and patients with high pre-spherical equivalent before ICL (OR = 1.09, 95% CI 1.03, 1.4).

CONCLUSION

Patients with higher axial length and higher pre-spherical equivalent before ICL implantation are at high risk of retinal complications.

Heterogenous thinning of peripapillary tissues occurs early during high myopia development in juvenile tree shrews

Myopia is an independent risk factor for glaucoma, but the link between both conditions remains unknown. Both conditions induce connective tissue remodeling at the optic nerve head (ONH), including the peripapillary tissues. The purpose of this study was to investigate the thickness changes of the peripapillary tissues during experimental high myopia development in juvenile tree shrews. Six juvenile tree shrews experienced binocular normal vision, while nine received monocular -10D lens treatment starting at 24 days of visual experience (DVE) to induce high myopia in one eye and the other eye served as control. Daily refractive and biometric measurements and weekly optical coherence tomography scans of the ONH were obtained for five weeks. Peripapillary sclera (Scl), choroid-retinal pigment epithelium complex (Ch-RPE), retinal nerve fiber layer (RNFL), and remaining retinal layers (RRL) were auto-segmented using a deep learning algorithm after nonlinear distortion correction. Peripapillary thickness values were quantified from 3D reconstructed segmentations. All lens-treated eyes developed high myopia (-9.8 ± 1.5 D), significantly different (P < 0.001) from normal (0.69 ± 0.45 D) and control eyes (0.76 ± 1.44 D). Myopic eyes showed significant thinning of all peripapillary tissues compared to both, normal and control eyes (P < 0.001). At the experimental end point, the relative thinning from baseline was heterogeneous across tissues and significantly more pronounced in the Scl (-8.95 ± 3.1%) and Ch-RPE (-16.8 ± 5.8%) when compared to the RNFL (-5.5 ± 1.6%) and RRL (-6.7 ± 1.8%). Furthermore, while axial length increased significantly throughout the five weeks of lens wear, significant peripapillary tissue thinning occurred only during the first week of the experiment (until a refraction of -2.5 ± 1.9 D was reached) and ceased thereafter. A sectorial analysis revealed no clear pattern. In conclusion, our data show that in juvenile tree shrews, experimental high myopia induces significant and heterogeneous thinning of the peripapillary tissues, where the retina seems to be protected from profound thickness changes as seen in Ch-RPE and Scl. Peripapillary tissue thinning occurs early during high myopia development despite continued progression of axial elongation. The observed heterogeneous thinning may contribute to the increased risk for pathological optic nerve head remodeling and glaucoma later in life.

Effect modification of time spent outdoors on the association between early childhood overweight and myopia: a one-year follow-up study

BACKGROUND

This study examined the moderating role of outdoor time on the relationship between overweight and myopia.

METHODS

The data for this study was obtained from a prospective study in Shanghai, where non-myopic children wore wristwear and were followed up for 1 year. Eye examinations were performed at each visit. The modification effect was assessed on the additive scale using multivariable logistic regression, and relative excess risk due to interaction was used to calculate the modification effect.

RESULTS

A total of 4683 non-myopic children were included with 32.20% being overweight at baseline. Following a 1-year period, 17.42% of children had myopia. When compared to those who spent <90 minutes outdoors, children who spent >120 had a relative risk of myopia onset that was reduced to 0.61. As time spent outdoors decreased, more risks of myopia onset were identified among overweight children than among normal children, the modification effect on the additive scale was -0.007, with ~70% of this effect attributed to the modifying influence of outdoor time.

CONCLUSIONS

Increasing outdoor time can reduce myopia more among overweight children than normal. Future interventions should focus on outdoor activities among overweight children to reduce myopia risks.

Vitamin D and myopia: a review

Myopia is a worldwide public health problem of vision disorder caused by multiple factors, which has posed a huge socioeconomic burden, raising concerns about sight-threatening ocular complications. Vitamin D, as a kind of fat-soluble vitamin, related to time-spent-outdoors, has been considered by extensive studies to have potential relationship with myopia. We reviewed studies published in a decade which estimated the association of blood vitamin D status with myopia and summarized the universality and individuality of all research articles. Several research articles suggested the known environmental risk factors of myopia, including age, gender, ethnicity, education level, parental and school conditions, time-spent-outdoors, and sunlight exposure, and recent epidemiological studies demonstrate that increased vitamin D levels, by virtue of the extended outdoor time, may be an important modifiable factor and a protective effect that delay the progression of myopia in children and adolescents rather than in adults. The genetic studies have been conducted to get access to the evidence of gene polymorphism for explaining the association of serum vitamin D status and myopia, but the precise genetic interpretation of vitamin D and myopia remains unclear so far; on the other hand, the possible mechanisms are various like copolymerization mechanism, calcium homeostasis and imbalance of ciliary muscle function regulation, but nearly all of the investigators are inclined to remain skeptical. This article reviews the age-related epidemiological proofs, existent genetics correlations, possible underlying biological mechanisms and further values for the protective association between vitamin D and myopia, providing the possibility of prevention or postponement for myopia.

Impact of removing soft contact lenses 1 day versus 1 month before surgery on the outcomes of microkeratome laser in situ keratomileusis

PURPOSE

To compare the outcomes, safety, efficacy, and predictability of microkeratome laser in situ keratomileusis (LASIK) 24 h and one month or more after removing soft contact lenses.

SETTING

ULTRALASIK Eye Center, Dubai, United Arab Emirates.

METHODS

The patients were divided based on the time of discontinuation of the soft contact lenses before LASIK (Group 1 at 24 h and Group 2 at one month or longer), and the two groups were well matched. Schirmer's testing, tear break-up time, corrected distance visual acuity, uncorrected distance visual acuity, manifest refraction spherical equivalent, and infection rate were evaluated preoperatively and at one week, one month, and six months after treatment.

RESULTS

Group 1 (G1) comprised 1025 eyes, and group 2 (G2) had 1052 eyes. The groups were comparable preoperatively. The overall-mentioned outcomes were comparable between groups with uncorrected distance visual acuity of - 0.084 ± 0.12 logMAR in G1 and - 0.078 ± 0.17 logMAR in the G2 at 6 months (P = 0.322). Tear break-up time as well as Schirmer's testing results was also comparable with no evidence of increased risk of dry eyes or non-inflammatory complications in any of the groups on follow-up visits at 1 week (P = 0.421), 1 month (P = 0.101), and 6 months (P = 0.399) postoperatively. Finally, no infectious complications were recorded in either of the groups.

CONCLUSION

With the absence of corneal warpage, no statistical or clinical difference in microkeratome LASIK outcomes and safety was spotted between the groups despite the difference in SCL discontinuation time before the procedure.

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.

Choroidal Morphology and Photoreceptor Activity Are Related and Affected by Myopia Development

Purpose

The choroid is critical for the regulation of eye growth and is involved in the pathogenesis of myopia-associated ocular complications. This study explores the relationship among choroidal biometry, photoreceptor activity, and myopic growth in marmosets (Callithrix jacchus) with lens-induced myopia.

Methods

A total of 34 common marmosets aged 92 to 273 days old were included in this study. Axial myopia was induced in 17 marmosets using negative soft contact lenses and 17 marmosets served as untreated controls. Cycloplegic refraction (RE) and vitreous chamber depth (VCD) were measured using autorefraction and A-scan ultrasonography, respectively. Choroidal scans were obtained using spectral-domain optical coherence tomography and binarized to calculate subfoveal choroidal thickness (ChT), total choroidal area (TCA), luminal area (LA), stromal area (SA), choroidal vascularity index (CVI), and LA/SA. To assess photoreceptor activity, the a-wave of the full-field electroretinogram was measured. Regression models were used to investigate the relationship between outcome measures.

Results

Eyes induced with axial myopia (RE = -7.14 ± 4.03 diopters [D], VCD = 6.86 ± 0.39 mm) showed significant reductions (4.92-21.24%) in all choroidal parameters (ChT, TCA, LA, SA, CVI, and LA/SA) compared to controls (RE = -1.25 ± 0.60 D, VCD = 6.58 ± 0.26 mm, all P < 0.05), which changed as a function of refraction and vitreous elongation, and were associated with a decrease in the a-wave amplitude. Further, multiple regression showed that a combination of ChT and CVI could well predict RE and VCD.

Conclusions

This study reports the existence of significant alterations in choroidal morphology in non-human primate eyes induced with myopia. The changes in choroidal anatomy were associated with reduced light-adapted a-wave amplitude. These findings may represent early markers for reduced visual performance and chorioretinal complications known to occur in eyes with large degrees of myopia.

Synchronous myopia development induced by bilateral form deprivation in chicks

Form deprivation (FD) is a widely employed experimental paradigm, typically used to induce unilateral myopia in animal models. This model is weakened by potential influence upon the FD eye from vision in the freely-viewing contralateral eye, which could be eliminated by imposing FD in both eyes; but while a few previous studies have explored the feasibility of inducing bilateral FD in chicks, substantial discrepancies in treatment outcomes were noted. Consequently, this study aimed to establish a bilateral FD myopia model in chicks, with validation by investigating the associated ocular growth patterns, feeding, and social behavior. Six-day-old chicks were treated with bilateral (n = 21) or unilateral (n = 10) FD for 12 days; the fellow untreated eyes in the unilateral FD group served as controls. Refractive error, corneal power, and ocular axial dimensions were measured at 4-day intervals after the onset of form deprivation, with a Hartinger refractometer, a custom-made videokeratography system, and a high-resolution A-scan ultrasonographer, respectively. Body weight was monitored to assess the chick's physical development. Our results showed that birds treated with bilateral FD grew as robustly as the unilaterally form-deprived chicks, with similar or slightly heavier body weights and mortalities. Unilateral FD induced significantly higher myopia in the treated eye, with stronger corneal power, deeper anterior and vitreous chambers, and longer axial length. Moreover, either bilaterally or unilaterally FD eyes developed similar refractive error (bilateral FD, left: -28.03 ± 9.06 D, right: -28.44 ± 9.45 D; unilateral FD: -29.48 ± 8.26 D) and ocular biometric changes; but choroidal thickness was thicker in bilaterally FD eyes, rather than thinner as in unilaterally FD eyes. In addition to the highly synchronized (symmetrical, parallel) development reported previously in bilateral FD, we found in this study that the correlations between bilaterally form-deprived eyes were highest for ocular biometric parameters directly contributing to myopia development, including corneal power (r = 0.74 to 0.93), anterior chamber depth (r = 0.60 to 0.85), vitreous chamber depth (r = 0.92 to 0.94), and axial length (r = 0.90 to 0.96). The remarkably synchronized growth pattern confirmed the feasibility of the bilateral FD paradigm for future research on myopia.

Factors Predicting the Need for Re-treatment After Laser Refractive Surgery in Patients With Mixed Astigmatism

PURPOSE

To identify risk factors that increase the likelihood of re-treatment following refractive surgery in patients with mixed astigmatism.

METHODS

This was a retrospective study including patients who underwent either laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) between 2000 and 2019 and had mixed astigmatism (spherical error of +0.50 D or greater and spherical equivalent of less than 0.00 diopters [D]). Patients were divided into two groups according to whether they underwent re-treatments during the study period.

RESULTS

Overall, 785 eyes (785 patients) were included. In total, 5.2% of the eyes (n = 41) underwent re-treatment. The re-treatment group was more likely to have preoperative high astigmatism (80.5% vs 48.3%, P < .001), moderate to high hyperopia (36.6% vs 22.3%, P = .035), and to have undergone surgery earlier during the study period (P < .001). They were also more likely to have undergone surgery using the Wave-Light EX200 rather than the EX500 laser platform (Alcon Laboratories, Inc) (P < .001), have a treated optical zone of 6 mm rather than 6.5 mm (P < .001 for both), and their maximum ablation depth was greater (P < .001). There was no difference between the re-treatment and control groups regarding procedure type (PRK vs LASIK). Binary logistic regression found preoperative high astigmatism (odds ratio = 3.97, P < .001) and the type of laser platform used (EX200, odds ratio = 7.78, P < .001) as the only independent factors associated with re-treatment.

CONCLUSIONS

Re-treatment rates following correction of mixed astigmatism were 5.2% over 20 years. Use of a sixth-generation laser platform significantly reduced the risk of re-treatment. Presence of high astigmatism is a significant risk factor for re-treatment. There was no difference in retreatment risk between PRK and LASIK. [J Refract Surg. 2024;40(2):e73-e78.].

Nutritional intake, environmental factors, and their impact on myopia prevalence in Korean children aged 5-12 years

BACKGROUND

Myopia is a complex condition influenced by numerous factors, including genetic predisposition, environmental factors, and lifestyle choices. Although evidence indicates that certain dietary factors may influence the development of myopia, this relationship is still not completely understood and is a topic of ongoing research.

METHODS

This study analyzed the relationship between dietary habits, environmental factors, and the prevalence of myopia in a sample of 24,345 children aged 5-12 years from the seventh Korea National Health and Nutrition Examination Survey (KNHANES VII). The average daily intake of dietary nutrients associated with the refractive error status of the participants was analyzed using analysis of variance (GLM) and the Scheffe method for post-hoc comparison. Multiple logistic regression analysis was conducted between the participant's refractive error status and daily dietary nutrient intake, while taking into consideration the age, sex, BMI, parental myopia, and near-work hours.

RESULTS

The risk of myopia increased with age, especially notable between ages 11 and 12, and was higher in children with both parents having myopia. Dietary factors played a crucial role; children with myopia had significantly lower intake of fat, omega-3 fatty acids, and retinol but higher intake of other nutrients compared to emmetropic and hyperopic counterparts. High consumption of carbohydrates, protein, phosphorus, iron, potassium, and sodium was associated with increased myopia risk. High sodium intake was particularly associated with a 2.05-fold increased myopia risk.

CONCLUSIONS

This study highlights the significant role of diet and lifestyle choices in the development of myopia in children. Our findings suggest the importance of considering these specific factors in the management and prevention strategies for myopia, underscoring the need for targeted interventions in children's health and vision care.

A Mendelian randomization study on the causal relationship between smoking, alcohol consumption, and the development of myopia and astigmatism

The influence of environmental factors like smoking and alcohol on myopia and astigmatism is controversial. However, due to ethical concerns, alternative study designs are urgently needed to assess causal inference, as mandatory exposure to cigarettes and alcohol is unethical. Following comprehensive screenings, 326 single nucleotide polymorphisms (SNPs) related to myopia and astigmatism were included in the dataset. To validate the causal association between exposures such as cigarette smoking, alcohol consumption, and coffee intake, and outcomes namely astigmatism and myopia, five regression models were employed. These models encompassed MR-Egger regression, random-effects inverse-variance weighted (IVW), weighted median estimator (WME), weighted model, and simple model. The instrumental variables utilized in these analyses were the aforementioned SNPs. Apply Cochran's Q test to determine heterogeneity of SNPs; if heterogeneity exists, focus on IVW model results. The IVW model showed a 1.379-fold increase in the risk of astigmatism (OR = 1.379, 95%CI 0.822~2.313, P = 0.224) and a 0.963-fold increase in the risk of myopia (OR = 0.963, 95%CI 0.666~1.393, P = 0.841) for each unit increase in smoking. For each unit increase in coffee intake, the risk of astigmatism increased 1.610-fold (OR = 1.610, 95%CI 0.444~5.835, P = 0.469) and the risk of myopia increased 0.788-fold (OR = 0.788, 95%CI 0.340~1.824, P = 0.578). For each additional unit of alcohol consumption, the risk of astigmatism increased by 0.763-fold (OR = 0.763, 95%CI 0.380~1.530, P = 0.446), and none of the differences were statistically significant. However, for each unit of alcohol consumption, the risk of myopia increased by 1.597 times, and the difference was statistically significant (OR = 1.597, 95%CI 1.023~2.493, P = 0.039). The findings indicate that alcohol consumption is a risk factor for myopia but smoking and coffee intake do not affect its development. Additionally, there is no association between smoking, alcohol consumption, coffee intake, and the risk of astigmatism.

Association of 10 Genetic Variations and 10 Environmental Factors with Myopia of Different Severities in Different Age Groups of People in Northeast China

BACKGROUND

To investigate the association of 10 genetic variations and 10 environmental factors with myopia of different severities in different age groups of children and adolescents in northeast China.

METHODS

Parental history and genetic testing for myopia-related susceptibility genes were carried out in a cohort of children and adolescents aged 2-17 years. In addition, 10 single nucleotide polymorphism (SNP) sites for genotyping and 10 environmental risk factors were selected, and the differences between site variation and environmental factors in different age groups with different degrees of myopia were explored.

RESULTS

A total of 2497 volunteers were recruited, including 2023 myopes and 474 non-myopes in the control group. From the cohort, 1160 subjects were sequenced for myopia SNP sites. Compared with the non-myopic group, the myopia of parents, outdoor activity less than 60 min per day, and a high-sugar diet were risk factors for developing myopia. Two syntrophin beta 1 (SNTB1) sites, rs4455882 and rs6469937 were found to be significantly associated with moderate myopia; fibroblast growth factor 10 (FGF10) rs339501 was significantly correlated with high myopia; and insulin-like growth factor 1 (IGF1) rs5742714 was significantly correlated with different degrees of myopia in the age group of <6 years. Finally, the FGF10 gene rs339501 SNP was significantly associated with moderate myopia and mild myopia in the 6- to 12-year-old age group.

CONCLUSIONS

Our results indicate that myopia is affected by both environmental and genetic factors. To prevent and control myopia, attention should be paid to the parental history of myopia, a high-sugar diet should be avoided, and outdoor time should be adjusted according to the average daily sunshine. In addition, it is necessary to pay attention to the increased risk of myopia in school-age children caused by SNTB1 rs4455882, FGF10 rs339501, and IGF1 rs5742714.

Lens-induced myopization and body weight in young guinea pigs

BACKGROUND

To investigate the relationship between body weight and Axial length in guinea pigs.

METHODS

Forty pigmented guinea pigs were randomly divided into two groups, namely control group and negative lens-induced myopization (LIM) group. After measuring the baseline axial length and body weight (BW), guinea pigs of LIM group received bilateral negative lens-induced myopization using - 10.0 diopters lenses. One week later, the lenses were removed and biometric and ophthalmoscopic examinations were repeated.

RESULTS

Two groups of guinea pigs showed no statistical difference in initial body weight and eye axis length. Compared to the control group, the lens-induced group had a lower weight (P = 0.02) and a longer axial length (P < 0.01) at the end of study Neither at baseline nor at week 1 did AL correlate with BW in both groups (Control Baseline: r = 0.306, P = 0.19; Control Week1: r = 0.333, P = 0.15; LIM Baseline: r=-0.142, P = 0.55; LIM Week 1: r = 0.189, P = 0.42). Lens-induction had a significant effect on axial elongation (P < 0.01) while body weight had no impact on such aspect (P > 0.05).

CONCLUSION

In guinea pigs of the same age, axial length was not correlated with body weight. Also, baseline body weight had no impact on natural axial length growth or lens-induced myopia. Lens-induction caused a significant reduction in body weight gain.

National estimate and associated factors of myopia among schoolchildren in Ethiopia: A systematic review and meta-analysis

INTRODUCTION

Myopia is a global public health concern that has a significant socioeconomic and psychological impact on schoolchildren. If Myopic patients are not detected early, they are exposed to retinal detachment, cataracts, and glaucoma. There have been previous studies conducted in Ethiopia, but there is significant inconsistency among studies. Hence, the aim of this study was to provide a single figure as well as associated factors for Myopia among Ethiopian schoolchildren.

METHOD

The national and international databases and gray literature were searched for important research articles. This review included school-based cross-sectional studies that were reported in English. The data were extracted using Microsoft word and exported to Stata™ Version 17.0 statistical software for further management and analysis .The presence of heterogeneity was checked using Cochrane Q test via fixed effects model and presented by forest plots with 95% CI. Due to the presence of substantial heterogeneity, I2 test using random effects model was computed to estimate the effect size. The existing heterogeneity among studies was explained by regional difference. To identify factors associated with myopia, meta regression was computed and significant factors was reported using OR with 95% CI.

RESULTS

In this systematic review and meta-analysis, 12 studies with a total of 9688 schoolchildren were included. The national estimate of myopia among schoolchildren in Ethiopia was 6.49% (95%CI: 4.86, 8.12). Having family history of myopia (OR: 9.18, 95%CI: 3.5,24.02) and being female (OR: 0.94, 95% CI: 0.50, 0.98) were the identified factors associated with myopia.

CONCLUSION

Myopia is one of the most prevalent childhood health condition in Ethiopia, which affects about one in every fourteen schoolchildren. Schoolchildren who had family history of myopia and being female were the identified risk factors of myopia among schoolchildren. Clinical and public engagement activities are needed to address the burden of myopia.

[Outbreak of myopia in pediatrics : management, prevention and treatment]

The worldwide incidence and prevalence of myopia has increased. The age of onset of this refractive disorder has inversely decreased. In addition to genetic and familial factors, environmental factors related to a sedentary lifestyle and activities in highly solicited near vision seem to have an impact on the development of axial myopia, that is an early and non-reversible elongation of the eyeball. Prevention of the development of myopia in pediatrics through simple daily measures plays therefore a fundamental role. In addition, pharmacological treatments, and specific optical treatments for controlling myopia have shown encouraging results in reducing the risk of long-term complications of progressive myopia, that is increased risk of developing cataract, glaucoma, retinal detachment, or maculopathy.

Bleb-related infection after primary trabeculectomy: medical chart reviews from 1993 to 2021

BACKGROUND

To investigate the incidence of and risk factors for bleb-related infection (BRI) in patients who underwent mitomycin C-augmented primary trabeculectomy.

METHODS

We reviewed the medical charts of consecutive patients who had received primary trabeculectomy in Taipei Veterans General Hospital. We recorded the demographic and clinical characteristics of patients before, during and after surgery. Furthermore, we recorded the time interval between surgery and infection onset, clinical manifestations and visual outcomes of patients with BRI. The cumulative incidence of BRI was estimated using the Kaplan-Meier method. A Cox proportional hazards model was used to explore factors associated with BRI.

RESULTS

In total, 1663 eyes were postoperatively followed up for 94.57±65.23 months. The cumulative incidence of BRI was 1.86 per 1000 person-years during the 28-year follow-up period: 24 (1.44%) patients developed BRI and 6 (0.36%) patients additionally developed endophthalmitis. A multivariate analysis revealed a significant association of BRI with wound manipulation, high myopia and hyperlipidaemia. Patients younger than 60 years were more likely to receive wound manipulation than their elderly counterparts (<0.001). One year after BRI, the best corrected visual acuity of the eyes with blebitis did not change significantly, whereas that of the eyes with endophthalmitis worsened significantly.

CONCLUSION

Risk factors for BRI after trabeculectomy include wound manipulation, high myopia and hyperlipidaemia. Considering myopia is highly prevalent throughout the world and is a risk factor for glaucoma, the lifelong risk of BRI after trabeculectomy in eyes with high myopia warrants the attention of ophthalmologists.

Association between body mass index and myopia in the United States population in the National Health and Nutrition Examination Surveys 1999 to 2008: a cross-sectional study

BACKGROUND

This study investigated the association between body mass index (BMI) and myopia in the United States.

METHODS

This cross-sectional study included 8,000 participants from the 1999 to 2008 National Health and Nutrition Examination Survey (NHANES). BMI was classified into four groups: < 18.5, 18.5 - 24.9, 25-29.9, and > 29.9. Three diagnostic thresholds were used for myopia A\B\C: spherical equivalent ≤ -0.5\-0.75\-1 diopters in the right eye. Multivariate logistic regression analysis and smooth curve fitting were performed to evaluate the association between BMI and myopia.

RESULTS

The incidence of myopia was 39.4%. BMI was correlated with myopia, with each 1 kg/m2 increase in BMI associated with a 1% increase in the risk of myopia (OR, 1.01; 95% CI 1.01 1.02; p < 0.05). In myopia B, after adjusting for confounding factors, compared with the reference group (BMI 18.5-24.9), participants with a BMI of 25-29.9 and greater than 29.9 had a 14% and 25% increased risk of myopia, respectively (OR 1.14; 95% CI 1.01 1.29; p = 0.037, OR 1.25; 95% CI 1.08 1.44; p = 0.003), which was similar to the results for myopic A (OR, 1.15; 95% CI 1.02 1.3; p = 0.027, OR 1.19; 95% CI 1.03 1.37; p = 0.018) and myopia C (OR 1.15; 95% CI 1.01 1.31; p = 0.035, OR 1.18; 95% CI 1.01 1.37; p = 0.032). Moreover, there was a linear relationship between myopia and BMI (p for nonlinearity = 0.767).

CONCLUSIONS

Myopia using all three diagnostic thresholds was positively associated with higher BMI. This suggests a potential association between myopia and higher BMI in the American population, warranting further investigations.

Significant myopic shift over time: Sixteen-year trends in overall refraction and age of myopia onset among Chinese children, with a focus on ages 4-6 years

Background

Myopia or near-sightedness is a major cause of blindness in China and typically develops between the ages of 6-12 years. We aimed to investigate the change in refractive error and the age of myopia onset in Chinese children from 2005 to 2021.

Methods

We first conducted a series of cross-sectional studies to determine the refractive states and the age of myopia onset over time, after which we analysed longitudinal data to investigate the dose-response relationship between hyperopic reserve and future risk of myopia. The analysis was based on the refraction data of children aged 4-18 years who visited the Fudan University Eye and Ear, Nose, and Throat (FUEENT) Hospital, a large tertiary hospital in Shanghai, China, for eye examinations between 2005 and 2021. We examined the prevalence of hyperopia (spherical equivalent refractive error (SERE) >0.75D), pre-myopia (-0.50D < SERE ≤ 0.75D), and myopia (SERE ≤-0.50D), the average SERE for each age group at the initial visit, the average age of myopia onset, and the safety threshold of hyperopic reserve against myopia onset.

Results

We included 870 372 eligible patients aged 4-18 years who attended examination between 2005 and 2021, 567 893 (65.2%) of whom were myopic at their initial visit to FUEENT. The mean SERE decreased in most (n/N = 14/15) of the age groups over the 16 calendar years, with a mean SERE for the whole cohort decreasing from -1.01D (standard deviation (SD) = 3.46D) in 2005 to -1.30D (SD = 3.11D) in 2021. The prevalence of pre-myopia increased over the 16 years (P < 0.001), while those of myopia and hyperopia remained largely stable (both P > 0.05). We observed a significant decrease in the prevalence of hyperopia (2005: 65.4% vs 2021: 51.1%; P < 0.001) and a significant increase in the prevalence of pre-myopia (2005: 19.0% vs 2021: 26.5%; P < 0.001) and myopia (2005: 15.6% vs 2021: 22.4%; P < 0.001) in children aged 4-6 years. We found an earlier myopia onset over time, with the mean age of onset decreasing from 10.6 years in 2005 to 7.6 years in 2021 (P < 0.001). Children with a hyperopic reserve of less than 1.50D were at increased risk of developing myopia during a median follow-up of 1.3 years.

Conclusions

We found an overall myopic shift in SERE in Chinese children aged 4-18 years over the past 16 years, particularly in those aged 4-6 years. The mean age of myopia onset decreased by three years over the same period. The "safety threshold" of hyperopic reserve we identified may help target the high-risk population for early prevention.

Myopia and sleep in children-a systematic review

Worldwide, approximately one in three people are myopic or short-sighted. Myopia in children is of particular concern as younger onset age implies a higher risk of progression, and consequently greater risk of developing vision-threatening complications. The importance of sleep in children's health has long been acknowledged, but evidence for its role in childhood myopia is fairly new and mixed results were presented across studies. To facilitate better understanding of this relationship, a broad literature search, up to and including October 31, 2022, was performed using three databases (PubMed, Embase, and Scopus). Seventeen studies were included in the review, covering four main aspects of sleep, namely duration, quality, timing, and efficiency, and their associations with myopia in children. The present literature review discussed these studies, revealed potential limitations in their methodologies, and identified gaps that need to be addressed in the future. The review also acknowledges that current evidence is insufficient, and the role of sleep in childhood myopia is far from being fully understood. Future studies that primarily, objectively, and accurately assess sleep and myopia, taking other characteristics of sleep beyond duration into consideration, with a more diverse sample in terms of age, ethnicity, and cultural/environmental background, and control for confounders such as light exposure and education load are much needed. Although more research is required, myopia management should be a holistic approach and the inclusion of sleep hygiene in myopia education targeting children and parents ought to be encouraged.

Ray-tracing-guided myopic LASIK: real-world clinical outcomes

PURPOSE

To assess effectiveness of individualized ray-trace based laser in situ keratomileusis (LASIK) for correction of myopia in everyday clinical practice.

SETTING

Single-site private practice.

DESIGN

Retrospective nonrandomised unmasked chart review.

METHODS

Consecutive, myopic eyes (range ≤-8.25 diopters [D] sphere; astigmatism 0 to -4.25 D) treated with ray-trace based LASIK were included. Patients underwent wavefront, tomography, and biometry assessment using the InnovEyes Sightmap diagnostic device. The ray-trace based algorithm (InnovEyes algorithm) then generated an individualized 3D eye model and calculated a customized LASIK ablation profile. Postoperative visual acuity, refractive error and whole eye higher-order aberrations (HOAs) were evaluated over 3 months.

RESULTS

The procedure was performed on 400 eyes (200 patients). Mean preoperative manifest refraction spherical equivalent was -3.39 ± 1.58 D (right eye -3.84 ± 1.63 D, left eye -3.98 ± 1.75 D). At month 3, uncorrected distance visual acuity (UDVA) was ≥20/20 in all eyes, ≥20/16 in 89% (right eye 90%, left eye 89%), ≥20/12 in 51% (54% right eye; 47% left eye), and 20/10 in 8% (right eye 8%; left eye 9%) of eyes respectively. UDVA was within 1 line of preoperative corrected distance visual acuity in 98% of eyes (right eye 98.5%; left eye 98%) and 39% of eyes (right eye 38%; left eye 39%) gained 1 line improvement. There was a statistically but not clinically significant increase in total HOAs (right eye 0.06 ± 0.133 μm; left eye 0.057 ± 0.125 μm; P < .001). The spherical aberration decreased (right eye -0.047 ± 0.095 μm, P < .001; left eye -0.051 ± 0.091 μm, P < .001).

CONCLUSIONS

Ray-trace based LASIK was safe and effective for correction of myopia with and without astigmatism. Approximately, half the eyes achieved ≥20/12.5 UDVA and 8% achieved 20/10. There was no clinically significant increase in total whole eye HOAs.

Effect of 3% Diquafosol Sodium on Dry Eye After Femtosecond Laser-Assisted In Situ Keratomileusis and Small Incision Lenticule Extraction Surgery in High-Myopic Eyes

PURPOSE

To evaluate the effect of 3% diquafosol sodium eye drop on dry eye after femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE) in high-myopic eyes.

METHODS

Eighty-one cases with high myopia (162 eyes) who received FS-LASIK or SMILE were divided into four groups by surgical design and tear film stability: D-FS-LASIK (5s

RESULTS

The D-SMILE group showed increase in BUT postoperatively (1m: P =0.006, 3m: P =0.004), whereas C-FS-LASIK (1m: P =0.012) and C-SMILE (1m: P =0.036) groups showed decrease in BUT. Higher ΔBUT were observed in D-FS-LASIK (1m: P =0.027) and D-SMILE (1m: P =0.001, 3m: P =0.012) postoperatively. The D-FS-LASIK group showed less decrease than C-FS-LASIK group in Schirmer I. The D-SMILE group showed increase in Schirmer I, whereas C-SMILE showed decrease in 3 months. ΔOSDI was lower in D-SMILE group than in C-SMILE group (1m: P =0.026, 3m: P =0.035). Fatigue was severer in D-SMILE group than in C-SMILE group preoperatively ( P =0.019), although there was no significant difference postoperatively. Objective scattering index (1m: P =0.002, 3m: P =0.021) and tear film objective scattering index (1m: P =0.005, 3m: P =0.010) were lower in D-FS-LASIK group than in C-FS-LASIK group postoperatively. The D-FS-LASIK group showed better VA20% ( P =0.036) and VA9% ( P =0.027) than the C-FS-LASIK group 1 month postoperatively.

CONCLUSIONS

3% Diquafosol sodium eye drop was effective for SMILE and FS-LASIK-related dry eye in high-myopic eyes. It is necessary to focus on perioperative anti-dry eye management and especially pay attention to the eyes with risk factors, including unstable tear film, high myopia, and FS-LASIK surgery.

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Key Words Collapse

MESH Headings

• Humans
• Keratomileusis, Laser In Situ/adverse effects
• Hyaluronic Acid/therapeutic use
• Myopia/etiology
• Dry Eye Syndromes/drug therapy
• Dry Eye Syndromes/etiology
• Dry Eye Syndromes/surgery
• Lasers, Excimer/therapeutic use
• Ophthalmic Solutions
• Corneal Stroma/surgery

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Grants

• No. Z201100005520043 Beijing Municipal Science and Technology Commission

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Affiliation(s)

Dengxin Gao Beijing Ophthalmology and Visual Science Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
Xiaotong Lv
Fengju Zhang
Yanzheng Song
Yushan Xu

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Effects of inflammation on myopia: evidence and potential mechanisms

As the most common type of refractive error, myopia has become one of the leading causes of visual impairment. With the increasing prevalence of myopia, there is a growing need to better understand the factors involved in its development. Inflammation, one of the most fundamental pathophysiological processes in humans, is a rapid response triggered by harmful stimuli and conditions. Although controlled inflammatory responses are necessary, over-activated inflammation is the common soil for many diseases. The impact of inflammation on myopia has received rising attention in recent years. Elevated inflammation may contribute to myopia progression either directly or indirectly by inducing scleral remodeling, and myopia development may also increase ocular inflammation. This article provides a comprehensive review of the interplay between inflammation and myopia and the potential biological mechanisms, which may present new targets for understanding the pathology of myopia and developing myopia therapies.

Comparison of biometric and refractive changes in intermittent exotropia with and without overminus lens therapy

BACKGROUND

Overminus lens is an effective non-surgical treatment of intermittent exotropia (IXT). Whether this treatment causes development of myopia is recently debated. This study evaluated ocular biometric changes in IXT children treated with and without overminus lens.

METHODS

Children with IXT were randomly assigned to control and overminus groups. Cycloplegic refraction, axial length and other parameters (keratometry, anterior chamber depth and lens thickness) were evaluated for up to 30 months and compared between the groups. Axial length to corneal curvature (AL/CR) ratio was examined as an indicator of myopia progression. Changes prior to and after overminus were also assessed in a subgroup.

RESULTS

Mean age of the total 84 subjects (58% women) was 7.2 years (range 4-15 years). Baseline refractive and biometric parameters of 39 control and 45 overminus subjects were not significantly different. Mean±SD change in refraction was -0.34±0.45D in controls and -0.41±0.66D in overminus group (p=0.527). AL increased by 0.29±0.20 millimetre (mm) in controls and 0.28±0.23 mm in overminus group (p=0.766). In the subgroup, the changes before and after overminus therapy was not significantly different (p>0.05). AL/CR ratio was maintained from baseline to follow-up visit (p=0.298) in both groups.

CONCLUSION

No significant differences in biometry or refraction were found between the two groups and before and after the therapy. We conclude that the overminus therapy in children, not accounting for other myopia risk factors, does not affect normal refractive growths.

Effects of blue light exposure on ocular parameters and choroidal blood perfusion in Guinea pig

PURPOSE

To investigate the impact of different duration of blue light exposure on ocular parameters and choroidal blood perfusion in guinea pigs with lens-induced myopia.

METHOD

Three-week-old Guinea pigs were randomly assigned to different light-environment groups. All groups were subjected to 12-h light/dark cycle. The control (NC) group was conditioned without intervention. While lens-induced myopia (LIM) groups had a -10D lens placed in the right eye and 0D in the left eye. The guinea pigs were exposed to increasing periods of blue-light (420 nm) environment for 3,6,9,12 h per day. Changes in refraction, axial length (AL), the radius of corneal curvature (CCR), choroidal thickness (ChT), and choroidal blood perfusion (ChBP)were measured in both LIM-eye and fellow-eye during the second and fourth week of LIM duration.

RESULTS

During the first two weeks of the experiment, blue light exposure raised ChBP and ChT, and the effect of suppressing myopia was proportional to the duration of blue light exposure. However, in the fourth week of the experiment, prolonged blue light (12BL) exposure led to a reduction in retinal thickness and the increase in ChT and ChBP ceased. Shorter blue light exposure had a better effect on myopia suppression, with all blue light groups statistically different from the LIM group.

CONCLUSION

Exposure to blue-light appears to have the potential to improve ChBP and ChT, thereby inhibiting the development of myopia. we speculate that blue-light inhibits the development of myopia for reasons other than longitudinal chromatic aberration (LCA). However,long-term exposure to blue-light may have adverse effects on ocular development. The next step is to investigate in depth the mechanisms by which the rational use of blue light regulates choroidal blood flow, offering new hope for the treatment of myopia.

Comparison of implantation of posterior chamber phakic IOL implantation and laser vision correction in terms of corneal endothelial cells: 3-year observational paired-eye study

PURPOSE

To compare the postoperative endothelial cell counts of EVO-implantable collamer lenses (ICLs) with a central hole (V4c and V5) and laser vision correction surgery (laser in situ keratomileusis or photorefractive keratectomy).

SETTING

B&VIIT Eye Center, Seoul, South Korea.

DESIGN

Retrospective observational and paired contralateral study.

METHODS

62 eyes of 31 patients who underwent EVO-ICLs with a central hole implantation in one eye (phakic intraocular lens [pIOL] group) and laser vision correction in the contralateral eye (LVC group) to correct refractive errors were retrospectively reviewed. Central endothelial cell density (ECD), percentage of hexagonal cells (HEX), coefficient of variation (CoV) in cell size, and adverse events were evaluated for at least 3 years. The endothelial cells were observed using a noncontact specular microscope.

RESULTS

All surgeries were performed, without complications during the follow-up period. The mean ECD loss values compared with the preoperative measurements were 6.65% and 4.95% during the 3 years after pIOL and LVC, respectively. There was no significant difference in ECD loss compared with the preoperative values (paired t test, P = .188) between the 2 groups. No significant loss in ECD was observed at any timepoint. The pIOL group showed higher HEX ( P = .018) and lower CoV ( P = .006) values than the LVC group at the last visit.

CONCLUSIONS

According to the authors' experience, the EVO-ICL with a central hole implantation was a safe and stable vision correction method. Moreover, it did not induce statistically significant changes in ECD at 3 years postoperatively compared with LVC. However, further long-term follow-up studies are required to confirm these results.

Effects of dopamine D2 receptor antagonists on retinal pigment epithelial/choroid complex metabolism in form-deprived myopic guinea pigs

The retinal pigment epithelial (RPE)/choroid complex regulates myopia development, but the precise pathogenesis of myopia remains unclear. We aimed to investigate the changes in RPE/choroid complex metabolism in a form deprivation myopia model after dopamine D2 receptor (D2R) modulation. Guinea pigs were randomly divided into normal (NC), form deprivation myopia (FDM), and FDM treated with dopamine D2R antagonist groups. Differential metabolites were screened using SIMCA-P software and MetaboAnalyst metabolomics analysis tool. Functions of differential metabolites were analyzed using KEGG enrichment pathways. Relative to the NC group, 38 differential metabolites were identified, comprising 29 increased metabolites (including nicotinic acid, cytosine, and glutamate) and 9 decreased metabolites, of which proline exhibited the largest decrease. Pathway analysis revealed regulation of arginine/proline and aspartate/glutamate metabolism. Intravitreal D2R antagonist injection increased proline concentrations and activated arginine/proline and purine metabolism pathways. In sum, D2R antagonists alleviated the myopia trend of refractive biological parameters in form deprivation myopic guinea pigs, suggesting the involvement of dopamine D2R signaling in myopia pathogenesis. The RPE/choroid may provide glutamate to the retina by activating proline metabolism via metabolic coupling with the retina. Dopamine D2R antagonism may modulate proline/arginine metabolic pathways in the RPE/choroid and regulate metabolism, information presentation, and myopia.

The effects of ambient narrowband long-wavelength light on lens-induced myopia and form-deprivation myopia in tree shrews

Here we examine the effects of ambient red light on lens-induced myopia and diffuser-induced myopia in tree shrews, small diurnal mammals closely related to primates. Starting at 24 days of visual experience (DVE), seventeen tree shrews were reared in red light (624 ± 10 or 634 ± 10 nm, 527-749 human lux) for 12-14 days wearing either a -5D lens (RL-5D, n = 5) or a diffuser (RLFD, n = 5) monocularly, or without visual restriction (RL-Control, n = 7). Refractive errors and ocular dimensions were compared to those obtained from tree shrews raised in broad-spectrum white light (WL-5D, n = 5; WLFD, n = 10; WL Control, n = 7). The RL-5D tree shrews developed less myopia in their lens-treated eyes than WL-5D tree shrews at the end of the experiment (-1.1 ± 0.9D vs. -3.8 ± 0.3D, p = 0.007). The diffuser-treated eyes of the RLFD tree shrews were near-emmetropic (-0.3 ± 0.6D, vs. -5.4 ± 0.7D in the WLFD group). Red light induced hyperopia in control animals (RL-vs. WL-Control, +3.0 ± 0.7 vs. +1.0 ± 0.2D, p = 0.02), the no-lens eyes of the RL-5D animals, and the no-diffuser eyes of the RLFD animals (+2.5 ± 0.5D and +2.3 ± 0.3D, respectively). The refractive alterations were consistent with the alterations in vitreous chamber depth. The lens-induced myopia developed in red light suggests that a non-chromatic cue could signal defocus to a less accurate extent, although it could also be a result of "form-deprivation" caused by defocus blur. As with previous studies in rhesus monkeys, the ability of red light to promote hyperopia appears to correlate with its ability to retard lens-induced myopia and form-deprivation myopia, the latter of which might be related to non-visual ocular mechanisms.

Retinal ganglion cells encode differently in the myopic mouse retina?

The etiology of myopia remains unclear. This study investigated whether retinal ganglion cells (RGCs) in the myopic retina encode visual information differently from the normal retina and to determine the role of Connexin (Cx) 36 in this process. Generalized linear models (GLMs), which can capture stimulus-dependent changes in real neurons with spike timing precision and reliability, were used to predict RGCs responses to focused and defocused images in the retinas of wild-type (normal) and Lens-Induced Myopia (LIM) mice. As the predominant subunit of gap junctions in the mouse retina and a plausible modulator in myopia development, Cx36 knockout (KO) mice were used as a control for an intact retinal circuit. The kinetics of excitatory postsynaptic currents (EPSCs) of a single αRGC could reflect projection of both focused and defocused images in the retinas of normal and LIM, but not in the Cx36 knockout mice. Poisson GLMs revealed that RGC encoding of visual stimuli in the LIM retina was similar to that of the normal retina. In the LIM retinas, the linear-Gaussian GLM model with offset was a better fit for predicting the spike count under a focused image than the defocused image. Akaike information criterion (AIC) indicated that nonparametric GLM (np-GLM) model predicted focused/defocused images better in both LIM and normal retinas. However, the spike counts in 33% of αRGCs in LIM retinas were better fitted by exponential GLM (exp-GLM) under defocus, compared to only 13% αRGCs in normal retinas. The differences in encoding performance between LIM and normal retinas indicated the possible amendment and plasticity of the retinal circuit in myopic retinas. The absence of a similar response between Cx36 KO mice and normal/LIM mice might suggest that Cx36, which is associated with myopia development, plays a role in encoding focused and defocused images.

Relative peripheral hyperopia leads to greater short-term axial length growth in White children with myopia

PURPOSE

Controversy exists regarding the influence of peripheral visual experience on the onset and progression of childhood myopia. This longitudinal, observational study evaluated the relationship between relative peripheral refraction (RPR) and changes in refractive error and axial length (AL) over 12 months in White children aged 6-7 and 12-13 years with a range of baseline refractive errors.

METHODS

Cycloplegic baseline autorefraction at horizontal retinal eccentricities of 0° and ±30° were recorded with the Shin-Nippon NVision-K 5001 while AL was measured using the Zeiss IOLMaster 700. Measurements were repeated after 12 months on a subgroup. Refractive data were transposed into power vectors as mean spherical equivalent (M), J0 and J45 . RPR was calculated by subtracting central from peripheral measurements. Participants were defined as myopic (M ≤ -0.50 D), premyopic (-0.50 D < M ≤ +0.75 D), emmetropic (+0.75 D < M < +2.00 D) or hyperopic (M ≥ +2.00 D).

RESULTS

Data were collected from 222 and 245 participants aged 6-7 and 12-13 years, respectively. Myopic eyes demonstrated, on average, more hyperopic RPR. Emmetropes and premyopes displayed emmetropic RPR, and hyperopes showed a myopic RPR. Fifty-six 6- to 7-year-olds and seventy 12- to 13-year-olds contributed 12-month repeated measures. Longitudinal data demonstrated a significant relationship between a more hyperopic RPR in the nasal retina and greater short-term axial elongation in teens with myopia at baseline (β = 0.69; p = 0.04). Each dioptre of relative peripheral hyperopia in the nasal retina was associated with an additional 0.10 mm (95% CI: 0.02-0.18 mm) annual increase in AL.

CONCLUSIONS

Hyperopic RPR in the nasal retina of myopic children is indicative of increased risk for rapid axial elongation and may be a useful metric to support decision-making in myopia management.

Prevalence and associated factors of myopia among school students in Shenyang, China: a cross-sectional study

Background

In recent years, the prevalence of myopia has increased significantly and caused great concern. Nevertheless, an estimate of myopia in the student population in Shenyang, Liaoning Province, China is still lacking. This study aims to determine the prevalence of myopia among students in Shenyang and investigate the associated factors affecting myopia development.

Methods

Standard logarithmic visual acuity chart and automatic computerized optometry under non-ciliary muscle paralysis were used to test the students' naked visual acuity of their right and left eyes. The included students were organized to fill in questionnaires on WeChat to collect the factors affecting myopia.

Results

A total of 34,644 students with a median age of 11.9 years were examined, including 17,563 males and 17,081 females. The overall prevalence of myopia was 60%, with a prevalence of 45% for mild myopia, 13% for moderate myopia, and 1.9% for high myopia. The sex, high educational stage, family history of myopia, doing homework after school or reading and writing for more than 2 h were associated with a higher risk of myopia, while doing eye exercises twice a day or more, going outdoors during recess, reading and writing with eyes more than one foot from books, and sleeping more than 8 h a day were associated factors for preventing myopia. The associated factors influencing myopia vary among different subgroups.

Conclusion

The prevalence of myopia in Shenyang is at a high level. In addition to sex, high educational stage and genetic factors, environmental factors including length of eye usage, eye exercises, outdoor activities, eye working distance, and sleep duration are associated with myopia prevalence. Therefore, it is recommended that the occurrence and development of myopia can be prevented by controlling the above environmental factors.

Exploring the relationship between intestinal flora and the pathological mechanism of myopia in adolescents from the perspective of Chinese and Western medicine: A review

The etiology of adolescent myopia involves genetic and environmental factors. The pathological mechanism of modern medicine includes blood perfusion, changes in blood molecules, neurotransmitters, and sclera remodeling. Chinese medicine believes that myopia is mainly related to the deficiency of liver blood and spleen and stomach disorders. The prevention and treatment of myopia in adolescents are very important, but in terms of the current incidence of myopia in adolescents and the level of clinical diagnosis and treatment, its prevention and treatment are insufficient. Modern medicine and traditional Chinese medicine both pay attention to integrity, so adolescent myopia should not only pay attention to eye changes but also pay attention to other body systems and other aspects of change. Intestinal flora has become a research hotspot in recent years, and it has been found that it is closely associated with multi-system and multi-type diseases. No studies have directly investigated the link between Intestinal flora and myopia in adolescents. Therefore, by summarizing the pathological mechanism of adolescent myopia and the connection between intestinal flora and the pathological mechanism of adolescent myopia, this paper analyzes the possible pathological mechanism of the influence of intestinal flora on adolescent myopia, providing a theoretical basis for future studies on the correlation between changes of intestinal flora and its metabolites and the incidence of adolescent myopia, which is of great significance for the study on the risk prediction of adolescent myopia.

Association between whole-grain intake and myopia in chinese children: a cross-sectional epidemiological study

BACKGROUND

Nutritional status influences the growth and development of the eyes. However, there are few studies on the association between diet, especially whole grains (WG) consumption, and myopia. The study aimed to evaluate the association between WG intake and myopia prevalence among primary school-age children in China.

METHODS

This cross-sectional epidemiological study conducted between November 2019 and December 2019 included 586 children, aged 6-12 years, attending primary school in Binhai district, Tianjin, China. Ophthalmologic examinations and optometric cycloplegic refraction measurements were conducted. Information was collected on known risks and protective factors for myopia and the consumption of WGs, vegetables, and fruits. This association between the probability of myopia and the proportion of WG consumption (WG proportion was calculated as the mean intake from WG sources divided by total grain intake), adjusted for protective and risk factors, was analysed using crude and multivariable logistic regression.

RESULTS

Among the study participants, 226/586 (38.57%) children had myopia in at least one eye. WG intake was inversely correlated with the prevalence of myopia. Furthermore, in the multivariate analysis, WG intake of > 50% was identified as a protective factor against myopia after subsequent adjustment for children's age, sex, parental myopia, near-work activity, screen time, reading and writing habits, visual fatigue, outdoor time, and classroom light environment (all P < 0.05).

CONCLUSION

WG intake (> 50%) was an independent protective factor against myopia. Modifying the form of grains consumed (whole versus refined) could be one of the targets of future public health measures.

Corneal Electrolysis for Granular Corneal Dystrophy Type 2 (Avellino Corneal Dystrophy) Exacerbation After LASIK

PURPOSE

To report two cases in which exacerbation of granular corneal dystrophy type 2 (GCD2; Avellino corneal dystrophy) after laser in situ keratomileusis (LASIK) was successfully removed by corneal electrolysis.

METHODS

This study involved a 66-year-old man and a 43-year-old man with GCD2 who had undergone bilateral LASIK for myopia 10 or more years prior to presentation. In both patients, GCD2 corneal opacity gradually developed postoperatively at the LASIK flap interface, thus resulting in a decrease of visual acuity. For treatment, the LASIK flaps in both patients were surgically lifted to directly remove the opacity. Corneal electrolysis was then applied to the back of each LASIK flap and stromal bed.

RESULTS

Postoperatively, the ocular symptoms and corneal opacities related to GCD exacerbation disappeared, with improvement of corrected and uncorrected distance visual acuity and almost no change of refractive error.

CONCLUSIONS

The findings reveal that corneal electrolysis is safe and effective for treating exacerbations of GCD2 following LASIK when applied to a surgically lifted flap, and that it successfully removes GCD2-related LASIK flap interface opacities with almost no change of refractive error postoperatively. [J Refract Surg. 2023;39(1):61-65.].

Compensation for Vitreous Chamber Elongation in Infancy and Childhood

SIGNIFICANCE

The ratios of diopters of change in refractive error produced per millimeter of eye elongation (D/mm) are rarely those predicted from geometric optics because of changes in other ocular components. Quantifying this optical compensation in millimeters instead of ratios reveals some important principles about eye growth and refractive error.

PURPOSE

The study purpose was to sort total vitreous chamber elongation into millimeters that either contributed (uncompensated) or did not contribute to change in refractive error (compensated).

METHODS

Participants were infants in the Berkeley Infant Biometry Study (n = 271, ages 3 months to 6 years) or schoolchildren in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (n = 456 emmetropes and 522 myopes, ages 6 to 14 years). Refractive error was measured using cycloplegic retinoscopy in infants (cyclopentolate 1%) and cycloplegic autorefraction in schoolchildren (tropicamide 1% or combined with cyclopentolate 1%). Axial dimensions were assessed using A-scan ultrasonography. Uncompensated millimeters were estimated from ratios of change in refractive error per millimeter of elongation using Gullstrand eye models. Compensated millimeters were the difference between measured elongation and uncompensated millimeters.

RESULTS

Compensated millimeters exceeded uncompensated millimeters in emmetropic children across ages, but uncompensated millimeters exceeded compensated millimeters in myopic children. Compensated millimeters were highest in infancy and decreased with age, reaching less than 0.10 mm per year by age 10 years in both myopic and emmetropic children. There were no statistically significant differences in compensated millimeters between myopic and emmetropic children between ages 8 and 14 years ( P values from .17 to .73).

CONCLUSIONS

The ability of the ocular components, primarily crystalline lens, to compensate for vitreous elongation is independent of the higher demands of myopic eye growth. The limited compensation after age 10 years suggests the target for elongation in myopia control needed to arrest myopia progression may be that seen in emmetropes or less.

Near work induces myopia in Guinea pigs

The association between near work activities and myopia has not been clearly established. This study establishes a model for near work myopia (NWM) induced by short viewing distance in guinea pigs with a carefully controlled visual environment, and evaluates the effect of viewing distance in myopia development. Pigmented guinea pigs (3 weeks old) were randomly assigned to 3 groups: near work (NW)-, form-deprivation (FD)-, and -4D hyperopic-defocus (HD)-induced myopia. Animals in NW groups were kept in cylindrical cages with vertical square-wave gratings, providing short- (S, d = 18 cm), middle- (M, d = 44 cm), and long- (L, d = 88 cm) mean viewing distances, all at the same illuminance, during daily treatment for 14 days. Biometric parameters, including refraction, anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD), and axial length (AL), were measured at the beginning and end of 14 days' treatment. Choroidal thickness (ChT) and choroidal blood perfusion (ChBP) were measured by optical coherence tomography (OCT) and OCT-angiography (OCTA), respectively, at the end of treatment. Refraction was shifted towards myopia in the S-cage group, compared with the M- and L-cage groups; refractions in the L-, M- and S-cage groups were 5.19 ± 0.65 D, 4.30 ± 0.64 D, and 0.53 ± 0.61 D, respectively (p < 0.001). VCD and AL in the S-cage group increased in parallel with the myopic shift (L vs M vs S: VCD: 3.15 ± 0.02 mm vs 3.17 ± 0.02 mm vs 3.26 ± 0.02 mm, p < 0.001; AL: 7.99 ± 0.03 mm vs 8.03 ± 0.03 mm vs 8.15 ± 0.02 mm, p = 0.001). In FD and HD eyes, changes similar to those in the S-cage group (near-work group, NW) were seen in refraction (NW vs FD vs HD: 5.36 ± 0.82 D vs -5.78 ± 0.44 D vs -4.96 ± 0.54 D, p = 0.734), ACD, LT, VCD and AL. Also, ChT and ChBP were significantly less in the S-cage group than in the M- and L-cage groups after 14 days' treatment (L vs M vs S: ChT: 74.84 ± 3.27 vs 76.07 ± 3.49 vs 61.95 ± 3.31, P = 0.002; ChBP: 48.32 ± 2.23 vs 48.66 ± 2.30 vs 38.14 ± 2.06, p = 0.002). Rearing in S-cages induced myopia in guinea pigs and correspondingly decreased ChBP and ChT. The present study provides objective evidence that short viewing distance could be a risk factor for myopia, and describes a useful model for studying the underlying mechanisms.

[Association of beverages intake with myopia among 11-14-year-old Chinese children in 2019-2021]

OBJECTIVE

To describe beverages intake and its association with myopia among 11-14-year-old children in China.

METHODS

Multi-stage stratified cluster random sampling was used and children aged 11 to 14 years were selected from 28 cities and rural areas in 14 provinces in China, and a total of 12 397 children were included in this study. Information including demographic characteristics, myopia status, dietary intake, physical activity, screen time, sleep duration were collected from questionnaire survey.

RESULTS

During 2019-2021, the prevalence of myopia among children aged 11 to 14 in China was 45.0%. The median beverages intake was 42.7 g/d. Children who did not drink beverages and whose beverages intake was &lt;150 g/d and ≥150 g/d accounted for 42.8%, 44.8% and 48.4%, respectively. Multivariate Logistic regression analysis showed that girls&apos; beverages intake ≥150 g/d was still a risk factor for the prevalence of myopia after controlling for confounding factors such as age, area, physical activity, screen time, sleep duration and intake of sugary food(OR=1.24, 95%CI 1.08-1.42, P&lt;0.05). Among children with myopia, mild myopia, moderate and above myopia accounted for 71.6% and 28.4% among boys and 73.8% and 26.3% among girls, respectively. There was no statistically significant regression between beverages intake and myopia in boys and girls regardless of whether confounding factors were adjusted(P &gt;0.05).

CONCLUSION

Children&apos;s beverages intake was generally common in China in 2019-2021. Children who consumed higher beverages were more likely to have myopia than that did not consume beverages.

[Relationship between sugary food intake and myopia in 11-14 years old Chinese children in 2019-2021]

OBJECTIVE

To investigate the relationship between the intake of sugary foods and the occurrence and development of myopia in children aged 11-14 in China.

METHODS

In the 28 urban and rural survey sites in 14 provinces that implemented the "China Children&apos;s Nutrition and Health System Survey and Application for 0-18 Years Old" project, a multi-stage stratified random cluster sampling method was adopted, and finally 12 397 adolescent children aged 11 to 14 were selected in the analysis. Demographic characteristics, myopia information and the intake of sugary food(cakes, preserved fruits, candies, chocolates and ice cream) were collected through questionnaires. Multifactor Logistic regression was used to analyze the relationship between sugary food intake and myopia in children.

RESULTS

The median daily intake of sugary foods(cakes, preserved fruits, candies, chocolates and ice cream)of 11-14 year old boys and girls in China was 11.4 g and 11.2 g respectively, 33.9% of boys and 34.2% of girls consumed ≥22 g of sugary food every day. The myopia rates of boys with intakes of &lt;2 g, 2-21 g and ≥22 g were 36.0%, 39.2% and 41.6%, and girls&apos; myopia rates were 45.9%, 51.8% and 55.1%. The result of Logistic regression analysis showed that after controlling for confounding factors such as age, gender, region, weekly high-intensity physical activity time, daily screen time, daily sleep time and daily intake of sugary beverages, compared with boys whose daily intake of sugary food was less than 2 g, the risk of myopia for boys whose daily intake of sugary food reached 2-21 g and ≥22 g was 1.18 and 1.23 times, for girls whose daily intake was less than 2 g, the risk of myopia was 1.27 times and 1.38 times for girls whose intake reached 2-21 g and ≥22 g(P&lt;0.05). No matter whether confounding factors were controlled or not, there was no correlation between the intake of sugary foods and the degree of myopia(P&gt;0.05).

CONCLUSION

The consumption of sugary food such as cakes, preserved fruits, candies, chocolates and ice cream among children aged 11 to 14 in China is common, and there is a certain degree of positive correlation with the prevalence of myopia, but no correlation is observed with the degree of myopia.

Outdoor exposure in children from Buenos Aires Province, Argentina

OBJECTIVES

To evaluate myopia risk factors, mainly outdoor exposure and reading habits, in a country with low prevalence of myopia (Buenos Aires Province, Argentina).

METHODS

Consecutive children interviewed in a clinical private practice setting were autorefracted under cycloplegia with cyclopentolate 1%. Their parents consented to fill a questionnaire about schooling, tutorial classes, outdoor exposure, reading habits, and cellphone use, both on weekdays and weekends. The Spanish questionnaire was based on past English questionnaires of myopia clinical trials. The spherical equivalent of the right eye was used for the refractive distribution. The average daily hours spent for each activity were calculated.

RESULTS

This study involved 115 children aged 10.48 ± 3.65 years (range 5-18 years), with 56.5% being girls. Children had 8 h of schooling per day in 62.6% of cases, and only 14.8 % had tutorial classes after school. There were 38.3% myopes (<-0.50 D), 24.3% hyperopes (>+2.00 D) and the rest were emmetropes. The mean time that these children spent outdoors per day was 3.94 ± 1.45 h (27.60 ± 10.16 h per week). The total mean time spent reading and writing per day was 1.50 ± 0.98 h, and that spent using cellphones and tablets was 2.43 ± 1.66 h.

CONCLUSION

In an environment with low myopia prevalence, children spend almoast 4 h per day outdoors, much more than the usual recommendation of 2 h a day for myopia prevention.

The role of ipRGCs in ocular growth and myopia development

The increasing global prevalence of myopia calls for elaboration of the pathogenesis of this disease. Here, we show that selective ablation and activation of intrinsically photosensitive retinal ganglion cells (ipRGCs) in developing mice induced myopic and hyperopic refractive shifts by modulating the corneal radius of curvature (CRC) and axial length (AL) in an opposite way. Melanopsin- and rod/cone-driven signals of ipRGCs were found to influence refractive development by affecting the AL and CRC, respectively. The role of ipRGCs in myopia progression is evidenced by attenuated form-deprivation myopia magnitudes in ipRGC-ablated and melanopsin-deficient animals and by enhanced melanopsin expression/photoresponses in form-deprived eyes. Cell subtype-specific ablation showed that M1 subtype cells, and probably M2/M3 subtype cells, are involved in ocular development. Thus, ipRGCs contribute substantially to mouse eye growth and myopia development, which may inspire novel strategies for myopia intervention.

Ocular and Nonocular Adverse Events during 3 Years of Soft Contact Lens Wear in Children

SIGNIFICANCE

Children are being fitted at younger ages with soft contact lenses for myopia control. This 3-year investigation of adverse events related to contact lens wear in 7- to 11-year-old participants helps optometrists understand what to expect when fitting children with soft contact lenses.

PURPOSE

The purpose of this article is to report the frequency and type of ocular and nonocular adverse events related to soft contact lens wear in children.

METHODS

Seven- to 11-year-old children wore soft contact lenses for 3 years. Adverse events were defined by a slit-lamp examination finding of grade 3 or worse; parental report of a clinically meaningful change (determined by the examiner) in eyes, vision, or health; or a clinically meaningful response (determined by examiner) to a symptom checklist. Adverse events were categorized and reported by examiners and finalized by the Executive Committee. The presence or absence of an infiltrate and a list of diagnoses was determined at the conclusion of the study.

RESULTS

The 294 participants wore their contact lenses 73.0 ± 26.5 hours per week, and 220 (74.8%) encountered at least 1 adverse event. Of the 432 adverse events, 75.2% were ocular, and 24.8% were nonocular. Contact lens wear was probably or definitely related to 60.6% of the ocular and 2.8% of the nonocular adverse events. None of the ocular adverse events were serious or severe or caused permanent contact lens discontinuation. The corneal infiltrate incidence was 185 cases per 10,000 patient-years of wear (95% confidence interval, 110 to 294). The incidence of moderate ocular adverse events that were definitely or probably related to contact lens wear was 405 cases per 10,000 patient-years of wear (95% confidence interval, 286 to 557).

CONCLUSIONS

The adverse events experienced by 7- to 11-year-old myopic children rarely required meaningful treatment and never led to permanent discontinuation of contact lens wear or loss of best-corrected vision.

Risk Factors for Myopia in 2 Hong Kong School Systems: A Pilot Study

PURPOSE

Myopia has reached "epidemic" proportions, especially in several East Asian countries. Most myopia emerges during childhood, particularly during the school years. The aim of this study was to investigate myopia prevalence and compare risk factors of myopia among Hong Kong Chinese primary school children under 2 different educational systems.

DESIGN

Cross-sectional study.

METHODS

Visual assessments were conducted in 1 government-funded primary school (n = 159) and 1 international school (n = 223) in Hong Kong in September and October 2018, respectively. Measurements were performed on children aged 8 to 10 years old. Noncycloplegic refraction and axial length were measured, respectively. A validated questionnaire focusing on demographic information, nonscreen time (eg, reading and writing on paper materials), screen time (ie, smartphones and tablets usage), time spent on outdoor activities, and other myopia risk factors was completed by parents of participants.

RESULTS

The prevalence of myopia [37.5% vs 12.8%, P < 0.001; spherical equivalent refraction (SER) ≤ -1.00 diopter (D)] and refractive astigmatism [25.0% vs 7.2%, P < 0.001; cylinder (Cyl) ≥ 1.00 diopter cylinder (DC)] were significantly higher in the local school than in the international school. Students in the local school were slightly older than those attending the international school (9.17 ± 0.82 years vs 8.95 ± 0.85 years, P = 0.046), and there was no significant difference in gender distribution between the 2 schools (P = 0.51). There were significant differences in the demographic information including parental myopia (P < 0.001), family income (P < 0.001), and parents' educational level (P < 0.001) between the 2 schools. Multiple regression analysis showed that parental myopia history and continuous near work was associated with myopia in the local school, while the father's educational level was related to myopia in the international school.

CONCLUSIONS

In this pilot study, despite the much higher prevalence of parental myopia and high myopia in the international school, the myopia prevalence among the students is lower in this school than in the local school, suggesting that environmental factors other than genetics might have a stronger protective effect in this school population.

Development of Refractive Parameters in 3- to 6-Year-Old Children and Its Application in Myopia Prediction and Intervention Guidance

OBJECTIVE

To investigate refractive development and prevalence of myopia in children aged 3-6 years in Hebei Province, China, and to explore the developmental law of refraction, so as to clinically guide the prediction and intervention of myopia.

METHODS

In May 2019, a total of 6120 people were inspected in 68 kindergartens in 11 cities in Hebei Province. Child refractive refraction was checked under noncycloplegia using a handheld binocular vision screener (SW-800, SUOER, Tianjin, China). Axial length (AL) and corneal radius of curvature (CR) were measured using an ocular biometry (IOLMaster 500, Carl Zeiss, Germany). Myopia was defined as spherical equivalent (SE) ≤ -0.75 D.

RESULTS

A total of 5506 children aged 3-6 years met the criteria and were included in the statistical analysis. The prevalence of myopia was 3.49% (1.93% at age 3, 2.90% at age 4, 3.78% at age 5, and 3.88% at age 6). Overall, the mean SE was +0.67 ± 1.05 D (+0.81 ± 1.00 D at age 3, +0.79 ± 1.05 D at age 4, +0.67 ± 1.08 D at age 5, and +0.13 ± 1.01 D at age 6); the mean CR was 7.76 ± 0.26 mm (7.78 ± 0.26 mm at age3, 7.75 ± 0.25 mm at age 4, 7.77 ± 0.26 mm at age 5, and 7.76 ± 0.25 mm at age 6); the mean AL was 22.31 ± 0.73 mm (21.98 ± 0.63 mm at age 3, 22.12 ± 0.69 mm at age 4, 22.34 ± 0.73 mm at age 5, and 22.49 ± 0.73 mm at age 6).

CONCLUSIONS

Prevalence of myopia increases with age in children aged 3-6 years in Hebei, China. With the increase of age, CR is basically stable, and AL increases gradually. AL/CR, which is closely related to SE, can be used as an indicator to predict myopia and guide clinical work.

Physical Activity Spaces Not Effective against Socioeconomic Inequalities in Myopia Incidence: The Generation R Study

SIGNIFICANCE

Our findings show that non-Dutch background, lower maternal education, and lower net household income level may be new risk factors for myopia development in the Netherlands. Newly introduced physical activity spaces may not be effective enough in increasing outdoor exposure in children to reduce eye growth.

PURPOSE

The aims of this study were to evaluate socioeconomic inequalities in myopia incidence, eye growth, outdoor exposure, and computer use and to investigate if newly introduced physical activity spaces can reduce eye growth in school-aged children.

METHODS

Participants (N = 2643) from the Dutch population-based birth cohort Generation R were examined at ages 6 and 9 years. Socioeconomic inequalities in myopia incidence, eye growth, and lifestyle were determined using regression analyses. Information on physical activity spaces located in Rotterdam was obtained. Differences in eye growth between those who became exposed to new physical activity spaces (n = 230) and those nonexposed (n = 1866) were evaluated with individual-level fixed-effects models.

RESULTS

Myopia prevalence was 2.2% at age 6 years and 12.2% at age 9 years. Outdoor exposure was 11.4 h/wk at age 6 years and 7.4 h/wk at age 9 years. Computer use was 2.1 h/wk at age 6 years and 5.2 h/wk at age 9 years. Myopia incidence was higher in children with non-Dutch background, and families with lower household income and lower maternal education (odds ratio [OR], 1.081 [95% confidence interval, 1.052 to 1.112]; OR, 1.035 [95% confidence interval, 1.008 to 1.063]; OR, 1.028 [95% confidence interval, 1.001 to 1.055], respectively). Children living <600 m of a physical activity space did not have increased outdoor exposure, except those from families with lower maternal education (β = 1.33 h/wk; 95% confidence interval, 0.15 to 2.51 h/wk). Newly introduced physical activity spaces were not associated with reduction of eye growth.

CONCLUSIONS

Children from socioeconomically disadvantaged families became more often myopic than those from socioeconomically advantaged families. We did not find evidence that physical activity spaces protect against myopia for the population at large, but subgroups may benefit.

Transient myopia as rare condition after neurosurgery

Refractive changes may be caused by systemic diseases such as diabetes mellitus, lupus erythematosus, or hypothyroidism. However, refractive changes following the removal of a brain tumour have not been reported. In our case report, we describe a young woman without any systemic disease. She came to the emergency department in our hospital, where she reported a headache on admission and no other difficulties. Vital computer tomography was performed at the emergency outpatient clinic. The frontoparietal round hypodense lesion with an indicated dense margin - suspicious abscess, was detected. The patient was admitted to the Neurological Department of Slovak Medical University to have her condition diagnosed. After magnetic resonance, she was admitted to the Neurosurgery department, she underwent a neurosurgical procedure, where the diffuse anaplastic glioma grade II was histopathologically confirmed. Afterward, she reported worsening of vision. We diagnosed transient myopia, which is a rare condition. One month after the procedure the patient's eyes were again emmetropic without any harm on eyes.

[Educational Environment: The Most Powerful Factor for the Onset and Development of Myopia among Students]

Based on the literature on myopia epidemiology, experiments of basic science, and clinical research, we have identified a number of major characteristics of the myopia problem. It was concluded that the student population of grades 1-12 showed high incidence of myopia and the problem was becoming increasingly more serious. Etiological investigations revealed the aggressive role played by environmental factors. Mature clinical correction methods were available, but there were still a multitude of uncertainties hampering the effort to slow the progression of myopia. Student myopia has become an issue of top concern in China's effort to prevent and control myopia. In order to approach the issue by dealing with problems in the educational environment and to explore for specific measures to prevent and control the onset and development of student myopia, it is important that we gain better understanding of the multiple effects on the onset and development of student myopia caused by the growing demand for education induced by high social development and the rapid changes in the educational environment caused by technological advancement. Approaching the problem from the perspective of the features of the eye and vision in the developmental stages of students of grades 1-12, and the study workload at each stage, this paper retrospectively reviewed the historical literature from the last 90 years and the data from cohort studies done before and after the outbreak of COVID-19. Identifying the education environment as the primary factor causing the onset and progression of student myopia, the paper fully recognizes the scientific rationality of and the specific role served by education-medicine synergy in student myopia prevention and control.