Complications of Pathologic Myopia

Handling missing data and measurement error for early-onset myopia risk prediction models

BACKGROUND

Early identification of children at high risk of developing myopia is essential to prevent myopia progression by introducing timely interventions. However, missing data and measurement error (ME) are common challenges in risk prediction modelling that can introduce bias in myopia prediction.

METHODS

We explore four imputation methods to address missing data and ME: single imputation (SI), multiple imputation under missing at random (MI-MAR), multiple imputation with calibration procedure (MI-ME), and multiple imputation under missing not at random (MI-MNAR). We compare four machine-learning models (Decision Tree, Naive Bayes, Random Forest, and Xgboost) and three statistical models (logistic regression, stepwise logistic regression, and least absolute shrinkage and selection operator logistic regression) in myopia risk prediction. We apply these models to the Shanghai Jinshan Myopia Cohort Study and also conduct a simulation study to investigate the impact of missing mechanisms, the degree of ME, and the importance of predictors on model performance. Model performance is evaluated using the receiver operating characteristic curve (AUROC) and the area under the precision-recall curve (AUPRC).

RESULTS

Our findings indicate that in scenarios with missing data and ME, using MI-ME in combination with logistic regression yields the best prediction results. In scenarios without ME, employing MI-MAR to handle missing data outperforms SI regardless of the missing mechanisms. When ME has a greater impact on prediction than missing data, the relative advantage of MI-MAR diminishes, and MI-ME becomes more superior. Furthermore, our results demonstrate that statistical models exhibit better prediction performance than machine-learning models.

CONCLUSION

MI-ME emerges as a reliable method for handling missing data and ME in important predictors for early-onset myopia risk prediction.

Machine Learning Models for Predicting Cycloplegic Refractive Error and Myopia Status Based on Non-Cycloplegic Data in Chinese Students

Purpose

To develop and validate machine learning (ML) models for predicting cycloplegic refractive error and myopia status using noncycloplegic refractive error and biometric data.

Methods

Cross-sectional study of children aged five to 18 years who underwent biometry and autorefraction before and after cycloplegia. Myopia was defined as cycloplegic spherical equivalent refraction (SER) ≤-0.5 Diopter (D). Models were evaluated for predicting SER using R2 and mean absolute error (MAE) and myopia status using area under the receiver operating characteristic (ROC) curve (AUC). Best-performing models were further evaluated using sensitivity/specificity and comparison of observed versus predicted myopia prevalence rate overall and in each age group. Independent data sets were used for training (n = 1938) and validation (n = 1476).

Results

In the validation dataset, ML models predicted cycloplegic SER with high R2 (0.913-0.935) and low MAE (0.393-0.480 D). The AUC for predicting myopia was high (0.984-0.987). The best-performing model for SER (XGBoost) had high sensitivity and specificity (91.1% and 97.2%). Random forest (RF), the best-performing model for myopia, had high sensitivity and specificity (92.2% and 96.9%). Within each age group, difference between predicted and actual myopia prevalence was within 4%.

Conclusions

Using noncycloplegic refractive error and ocular biometric data, ML models performed well for predicting cycloplegic SER and myopia status. When measuring cycloplegic SER is not feasible, ML may provide a useful tool for estimating cycloplegic SER and myopia prevalence rate in epidemiological studies.

Translational Relevance

Using ML to predict cycloplegic refraction based on noncycloplegic data is a powerful tool for large, population-based studies of refractive error.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Comparison of macular changes and visual outcomes between femtosecond laser-assisted cataract surgery and conventional phacoemulsification surgery for high myopic cataract patients

BACKGROUND

To evaluate differences in log MAR best-corrected visual acuity (BCVA) improvement and postoperative central foveal thickness (CFT) and choroidal thickness (CT) changes between conventional phacoemulsification surgery (CPS) and femtosecond laser-assisted cataract surgery (FLACS) for high-myopia cataracts.

METHODS

This was a retrospective and observational study. One hundred and two eyes of 102 patients with high-myopia cataracts were examined. CPS was performed in 54 eyes, and FLACS was performed in 48 eyes. All eyes underwent logMAR BCVA, CFT and CT of three different sectors preoperatively and one week and six months postoperatively.

RESULTS

The logMAR BCVA improved significantly after surgery in both groups (both P < 0.001), but no difference was observed in BCVA improvement between the groups (P = 0.554). Moreover, no significant differences were reflected in the changes in CFT, nasal 1 mm CT or temporal 1 mm CT between the two groups, and only subfoveal choroidal thickness (SFCT) in the CPS group decreased significantly compared with that in the FLACS group at any postoperative time (P = 0.003 and 0.026). AL, preoperative logMAR BCVA, and CT of the three regions exhibited a notable correlation with postoperative BCVA (all P < 0.05) according to univariate logistic regression analysis. However, only the AL, preoperative logMAR BCVA and SFCT remained significant in the multivariate model. Postoperative logMAR BCVA revealed a positive correlation with AL and preoperative logMAR BCVA but a negative correlation with SFCT.

CONCLUSIONS

FLACS was not superior to CPS in improving BCVA but had less impact on SFCT in the treatment of high-myopia cataracts. Eyes with a longer AL, worse preoperative logMAR BCVA and thinner SFCT had a high risk of worse postoperative BCVA.

Longitudinal analysis of refraction and ocular biometrics in preschool children with early-onset high myopia

We investigated changes in refraction and ocular biometrics in preschool children with early-onset high myopia. Sixty eyes of 60 children with a mean follow-up time of 58.5 months were included in this study. At baseline, mean age of children was 55.6 ± 13.1 months, mean spherical equivalent (SE) was - 8.59 ± 2.66 D, and 25.64 ± 1.16 mm for axial length (AL). The total annual rate of myopic progression and axial elongation were - 0.37 ± 0.39 D/year and 0.33 ± 0.18 mm/year, respectively. During follow-up period, there was a trend toward less myopic progression and axial elongation over time. Of the total participants, 24 children (40%) were in the myopia progression group and the remaining 36 children (60%) were in the myopia stability group. In multiple linear regression analysis, baseline SE and AL were independently associated with myopic progression, while age, sex, and baseline AL-to-CR ratio were not related to myopic progression. According to the model, more myopic SE (β = - 0.186, P = 0.035) and longer AL (β = - 0.391, P = 0.008) at baseline were significantly associated with myopic progression. Myopia progression in preschoolers with high myopia tended to be relatively modest, with 60% of subjects exhibited myopic stability. Higher myopic SE, and longer AL at baseline were associated with myopic progression in preschool children with high myopia.

Secondhand smoke exposure and ocular health: A systematic review

The toxicology of secondhand smoke (SHS), along with the harm of its exposure to human health, has been generally acknowledged; however, specific evidence is lacking on the association between SHS exposure and ocular health. In this systematic review (PROSPERO registration number: CRD42022247992), we included 55 original articles published by 12 May 2023, which dealt with SHS exposure and ocular disorders, such as eye irritation, conjunctivitis, dry eye diseases, uveitis, myopia, astigmatism, contact lens discomfort, age-related macular degeneration, glaucoma, and thyroid eye disease that addressed the ocular neurovascular structures of the macular, retinal nerve fiber layer, choroid, and corneal biomechanical parameters. We found compelling correlational evidence for eye irritation, conjunctivitis, and dry eye symptoms-supporting that SHS exposure was positively associated with inflammatory and allergic changes in the eyes. Yet, evidence about the associations between SHS exposure and other ocular disorders, structures, and parameters is still limited or controversial. Given the limitations of existing literature, more investigations with high quality and rigorous design are warranted to elucidate the potentially harmful effects of SHS exposure on ocular health.

Oral administration of caffeine metabolite 7-methylxanthine is associated with slowed myopia progression in Danish children

PURPOSE

Myopia is associated with an increased risk of permanent vision loss. The caffeine metabolite 7-methylxanthine (7-MX), licensed in Denmark since 2009 as a treatment to reduce the rate of childhood myopia progression, is the only orally administered therapy available. The purpose of the current study was to assess the rate of myopia progression in children taking 7-MX.

METHODS

Longitudinal cycloplegic refraction and axial length data for 711 myopic children from Denmark treated with varying doses of oral 7-MX (0-1200 mg per day) were analysed using linear mixed models.

RESULTS

The median age at baseline was 11.1 years (range 7.0 -15.0 years). Children were followed for an average of 3.6 years (range 0.9-9.1 years) and the average myopia progression was 1.34 dioptres (D) (range -6.50 to +0.75 D). Treatment with 7-MX was associated with a reduced rate of myopia progression (p<0.001) and axial elongation (p<0.002). Modelling suggested that, on average, an 11-year-old child taking 1000 mg 7-MX daily would develop -1.43 D of myopia over the next 6 years, compared with -2.27 D if untreated. Axial length in this child would increase by 0.84 mm over 6 years when taking a daily dose of 1000 mg of 7-MX, compared with 1.01 mm if untreated. No adverse effects of 7-MX therapy were reported.

CONCLUSIONS

Oral intake of 7-MX was associated with reduced myopia progression and reduced axial elongation in this sample of myopic children from Denmark. Randomised controlled trials are needed to determine whether the association is causal.

Choroidal Vascular Density Quantification in High Myopia with or without Choroidal Neovascularization Using Optical Coherence Tomography Angiography

Purpose

The aim of this study was to analyze choroidal vascular density alteration in high myopia with or without choroidal neovascularization by using optical coherence tomography angiography (OCTA).

Methods

This was a cross-sectional, observational study that included 60 high-myopia eyes. All the participants had comprehensive ophthalmic assessments with visual acuity, intraocular pressure, slit lamp-assisted biomicroscopy, color fundus photography, axial length, optometry, and OCTA. Age, sex, and comorbidities were collected from their medical charts. Univariate and multiple analyses were made to compare the age, spherical equivalent, choroidal vascular density, gender, and choroidal thickness between normal and patients with choroidal neovascularization.

Results

60 eyes with high myopia were included in our study, including 30 eyes with choroidal neovascularization and 30 eyes without choroidal neovascularization or other fundus pathology. The mean age of high myopic patients was older in the choroidal neovascularization group than in the normal group (48.43 ± 19.06 years vs. 28.83 ± 9.92 years, p < 0.01). The mean choroidal thickness of high myopic patients was thinner in the neovascularization group than in the normal group (68.81 ± 48.81 μm vs. 137.80 ± 66.33 μm, p < 0.01). The mean choroidal vascular density in the normal group was greater than in the choroidal neovascularization group (82.43 ± 8.73 vs. 67.54 ± 12.56, p < 0.01). There was no significant difference in spherical equivalent between the choroidal neovascularization group and the normal group (-10.56 ± 2.97D vs. -11.93 ± 3.38D, p = 0.11). Multivariate analysis showed that after adjusting for covariates, less choroidal vascular density and older age were independent factors associated with choroidal neovascularization in the high myopic eye.

Conclusion

Decreased choroidal vascular density and older age played an important role in the development of choroidal neovascularization in high myopic eyes. OCTA may help us to identify the highly myopic patients that need to intervene.

Automated detection of myopic maculopathy using five-category models based on vision outlooker for visual recognition

Purpose

To propose a five-category model for the automatic detection of myopic macular lesions to help grassroots medical institutions conduct preliminary screening of myopic macular lesions from limited number of color fundus images.

Methods

First, 1,750 fundus images of non-myopic retinal lesions and four categories of pathological myopic maculopathy were collected, graded, and labeled. Subsequently, three five-classification models based on Vision Outlooker for Visual Recognition (VOLO), EfficientNetV2, and ResNet50 for detecting myopic maculopathy were trained with data-augmented images, and the diagnostic results of the different trained models were compared and analyzed. The main evaluation metrics were sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), area under the curve (AUC), kappa and accuracy, and receiver operating characteristic curve (ROC).

Results

The diagnostic accuracy of the VOLO-D2 model was 96.60% with a kappa value of 95.60%. All indicators used for the diagnosis of myopia-free macular degeneration were 100%. The sensitivity, NPV, specificity, and PPV for diagnosis of leopard fundus were 96.43, 98.33, 100, and 100%, respectively. The sensitivity, specificity, PPV, and NPV for the diagnosis of diffuse chorioretinal atrophy were 96.88, 98.59, 93.94, and 99.29%, respectively. The sensitivity, specificity, PPV, and NPV for the diagnosis of patchy chorioretinal atrophy were 92.31, 99.26, 97.30, and 97.81%, respectively. The sensitivity, specificity, PPV, and NPV for the diagnosis of macular atrophy were 100, 98.10, 84.21, and 100%, respectively.

Conclusion

The VOLO-D2 model accurately identified myopia-free macular lesions and four pathological myopia-related macular lesions with high sensitivity and specificity. It can be used in screening pathological myopic macular lesions and can help ophthalmologists and primary medical institution providers complete the initial screening diagnosis of patients.

Ocular biometrics and uncorrected visual acuity for detecting myopia in Chinese school students

The study is to evaluate the performance of ocular biometric measures and uncorrected visual acuity (UCVA) for detecting myopia among Chinese students. Among 5- to 18-year-old Chinese students from two cities of China, trained eye-care professionals performed assessment of ocular biometrics (axial length (AL), corneal curvature radius (CR), anterior chamber depth) under noncycloplegic conditions using NIDEK Optical Biometer AL-Scan, distance visual acuity using retro-illuminated logMAR chart with tumbling-E optotypes, and cycloplegic refractive error using NIDEK autorefractor with administration of 0.5% tropicamide. Spherical equivalent (SER) in diopters (D) was calculated as sphere plus half cylinder, and myopia was defined as SER ≤ - 0.5 D. Performances of ocular biometrics and UCVA (individually and in combination) for detecting myopia were evaluated using sensitivity and specificity, predictive values, and area under ROC curve (AUC) in both development dataset and validation dataset. Among 3436 students (mean age 9.7 years, 51% female), the mean (SD) cycloplegic SER was - 0.20 (2.18) D, and 1269 (36.9%) had myopia. Cycloplegic SER was significantly correlated with AL (Pearson Correlation coefficient r = - 0.82), AL/CR ratio (r = - 0.90), and UCVA (r = 0.79), but was not correlated with CR (r = 0.02, p = 0.15). The AL/CR ratio detected myopia with AUC 0.963 (95% CI 0.957-0.969) and combination with UCVA improved the AUC to 0.976 (95% CI 0.971-0.981). Using age-specific AL/CR cutoff (> 3.00 for age < 10 years, > 3.06 for 10-14 years, > 3.08 for ≥ 15 years) as myopia positive, the sensitivity and specificity were 87.0% (95% CI 84.4-89.6%) and 87.8% (86.0-89.6%), respectively, in the development dataset and 86.4% (95% CI 83.7-89.1%) and 89.4% (95% CI 87.3-91.4%), respectively, in the validation dataset. Combining AL/CR and UCVA (worse than 20/32 for age < 10 years, and 20/25 for ≥ 10 years) provided 91.9% (95% CI 90.4-93.4%) sensitivity and 87.0% (95% CI 85.6-88.4%) specificity, positive value of 80.6% (95% CI 78.5-82.6%) and negative value of 94.8% (95% CI 93.8-95.8%). These results suggest that AL/CR ratio is highly correlated with cycloplegic refractive error and detects myopia with high sensitivity and specificity,  AL/CR ratio alone or in combination with UCVA can be used as a tool for myopia screening or for estimating myopia prevalence in large epidemiological studies with limited resources for cycloplegic refraction.

The Connection between High Myopia Patients and MiR-708a or MiR-148 Expression Levels in Aqueous Studies of Visual Acuity

Myopia goes far beyond the inconvenience it brings. It is a prevailing and vision-threatening eye disease, especially in Asia. Aberrantly expressed miR-708a and miR-148 are critical for accurate diagnosis, good prognosis, and precise response prediction of myopia. In this paper, we aim to examine the potential contributions of miR-708a, miR-148a, and PAX6 to high myopia (HM). First, aqueous samples were taken from 25 exclusively HM eyes and 25 exclusively cataract eyes. For next-generation sequencing and bioinformatics analysis, RNA from sample 30one was used. Twenty more samples were used for RT-qPCR. 341 miRNAs in total were found in HM eyes; 249 mature miRNAs and 17 new miRNAs showed differential expression. The expression of hsa-miR-127-3p, hsa-let-7i-5p, and hsa-miR-98-5p was identified using RT-qPCR. MiR-708a and miR-148, which may be linked to the development of myopia and serve as possible biomarkers, are notably highly expressed in atrial tissues of HM patients. Our findings may help deepen the understanding of the mechanisms behind the high expression of miR-708a and miR-148 in atrial tissues of patients with HM.

Development of a deep learning algorithm for myopic maculopathy classification based on OCT images using transfer learning

Purpose

To apply deep learning (DL) techniques to develop an automatic intelligent classification system identifying the specific types of myopic maculopathy (MM) based on macular optical coherence tomography (OCT) images using transfer learning (TL).

Method

In this retrospective study, a total of 3,945 macular OCT images from 2,866 myopic patients were recruited from the ophthalmic outpatients of three hospitals. After culling out 545 images with poor quality, a dataset containing 3,400 macular OCT images was manually classified according to the ATN system, containing four types of MM with high OCT diagnostic values. Two DL classification algorithms were trained to identify the targeted lesion categories: Algorithm A was trained from scratch, and algorithm B using the TL approach initiated from the classification algorithm developed in our previous study. After comparing the training process, the algorithm with better performance was tested and validated. The performance of the classification algorithm in the test and validation sets was evaluated using metrics including sensitivity, specificity, accuracy, quadratic-weighted kappa score, and the area under the receiver operating characteristic curve (AUC). Moreover, the human-machine comparison was conducted. To better evaluate the algorithm and clarify the optimization direction, the dimensionality reduction analysis and heat map analysis were also used to visually analyze the algorithm.

Results

Algorithm B showed better performance in the training process. In the test set, the algorithm B achieved relatively robust performance with macro AUC, accuracy, and quadratic-weighted kappa of 0.986, 96.04% (95% CI: 0.951, 0.969), and 0.940 (95% CI: 0.909-0.971), respectively. In the external validation set, the performance of algorithm B was slightly inferior to that in the test set. In human-machine comparison test, the algorithm indicators were inferior to the retinal specialists but were the same as the ordinary ophthalmologists. In addition, dimensionality reduction visualization and heatmap visualization analysis showed excellent performance of the algorithm.

Conclusion

Our macular OCT image classification algorithm developed using the TL approach exhibited excellent performance. The automatic diagnosis system for macular OCT images of MM based on DL showed potential application prospects.

Temporal and spatial characterization of myopia in China

Purpose

The aim of this study was to characterize the temporal and spatial distribution of myopia among students aged 7-18 years, by analyzing the aggregation area and providing the basis for the prevention and control of myopia in China.

Methods

A database for the spatial analysis of myopia in China during 1995-2014 was established using ArcGIS10.0 software as a platform for data management and presentation. A spatial autocorrelation analysis of myopia was undertaken, and a temporal and spatial scan analysis was performed using SaTScan9.5 software.

Results

Our data demonstrated that the prevalence of myopia in China in 1995, 2000, 2005, 2010, and 2014 was 35.9, 41.5, 48.7, 57.3, and 57.1%, respectively, thus indicating a gradual upward trend. The prevalence of myopia was analyzed in various provinces (municipalities and autonomous regions), and the highest was found in Jiangsu Province, with an average Moran's I index of 0.244295 in China (P ≤ 0.05). According to the local Moran's I autocorrelation analysis, there was a spatial aggregation of myopia prevalence among students in the entire country, with Shandong, Jiangsu, Anhui, and Shanghai being classified as high-high aggregation areas, while Hainan and Guangxi were classified as low-low aggregation areas. In addition, the Getis-Ord General G results of the global hotspot analysis showed a countrywide myopia prevalence index of 0.035020 and a Z score of 1.7959 (P = 0.07251). Because the myopia prevalence correlation difference was not statistically significant, there were no "positive hotspots" or "negative hotspots." The local hotspot analysis shows that Shandong and Jiangsu belong to high-value aggregation areas, while Hainan and Guizhou belong to low-value aggregation areas. Further analysis using time-space scanning showed 15 aggregation regions in five stages, with four aggregation regions having statistically significant differences (P ≤ 0.05). However, the aggregation range has changed over time. Overall, from 1995 to 2014, the aggregation areas for the myopia prevalence in Chinese students have shifted from the northwest, north, and northeast regions to the southeast regions.

Conclusion

Our data demonstrate that, from 1995 to 2014, the prevalence of myopia increased in students aged 7-18 years in China. In addition, the prevalence of myopia is randomly distributed in various provinces (municipalities and autonomous regions) and exhibits spatial aggregation. Also, the gathering area is gradually shifting to the southeast, with the existence of high-risk areas. It is, therefore, necessary to focus on this area and undertake targeted prevention and control measures.

Form-deprivation myopia downregulates calcium levels in retinal horizontal cells in mice

The process of eye axis lengthening in myopic eyes is regulated by multiple mechanisms in the retina, and horizontal cells (HCs) are an essential interneuron in the visual regulatory system. Wherein intracellular Ca²⁺ plays an important role in the events involved in the regulatory role of HCs in the retinal neural network. It is unknown if intracellular Ca²⁺ regulation in HCs mediates changes in the retinal neural network during myopia progression. We describe here a novel calcium fluorescence indicator system that monitors HCs' intracellular Ca²⁺ levels during form-deprivation myopia (FDM) in mice. AAV injection of GCaMP6s, as a protein calcium sensor, into a Gja10-Cre mouse monitored the changes in Ca²⁺signaling in HC that accompany FDM progression in mice. An alternative Gja10-Cre/Ai96-GCaMP6s mouse model was created by cross mating Gja10-Cre with Ai96 mice. Immunofluorescence imaging and live imaging of the retinal cells verified the identity of these animal models. Changes in retinal horizontal cellular Ca²⁺ levels were resolved during FDM development. The numbers of GCaMP6s and the proportion of HCs were tracked based on profiling changes in GCaMP6s⁺calbindin⁺/calbindin⁺ coimmunostaining patterns. They significantly decreased more after either two days (P < 0.01) or two weeks (P < 0.001) in form deprived eyes than in the untreated fellow eyes. These decreases in their proportion reached significance only in the retinal central region rather than also in the retinal periphery. A novel approach employing a GCaMP6s mouse model was developed that may ultimately clarify if HCs mediate Ca²⁺ signals that contribute to controlling FDM progression in mice. The results indicate so far that FDM progression is associated with declines in HC Ca²⁺ signaling activity.

PDE4B Proposed as a High Myopia Susceptibility Gene in Chinese Population

Myopia is the most common cause of refractive error worldwide. High myopia is a severe type of myopia, which usually accompanies pathological changes in the fundus. To identify high myopia susceptibility genes, DNA-pooling based genome-wide association analysis was used to search for a correlation between single nucleotide polymorphisms and high myopia in a Han Chinese cohort (cases vs. controls in discovery stage: 507 vs. 294; replication stage 1: 991 vs. 1,025; replication stage 2: 1,021 vs. 52,708). Three variants (rs10889602T/G, rs2193015T/C, rs9676191A/C) were identified as being significantly associated with high myopia in the discovery, and replication stage. rs10889602T/G is located at the third intron of phosphodiesterase 4B (PDE4B), whose functional assays were performed by comparing the effects of rs10889602T/T deletion of this risk allele on PDE4B and COL1A1 gene and protein expression levels in the rs10889602T/T^del/del, rs10889602T/T^del/wt, and normal control A549 cell lines. The declines in the PDE4B and COL1A1 gene expression levels were larger in the rs10889602T/T deleted A549 cells than in the normal control A549 cells (one-way ANOVA, p < 0.001). The knockdown of PDE4B by siRNA in human scleral fibroblasts led to downregulation of COL1A1. This correspondence between the declines in rs10889602 of the PDE4B gene, PDE4B knockdown, and COL1A1 protein expression levels suggest that PDE4B may be a novel high myopia susceptibility gene, which regulates myopia progression through controlling scleral collagen I expression levels. More studies are needed to determine if there is a correlation between PDE4B and high myopia in other larger sample sized cohorts.

Prediction for Cycloplegic Refractive Error in Chinese School Students: Model Development and Validation

Purpose

To predict cycloplegic refractive error using measurements obtained under noncycloplegic conditions.

Method

Refractive error was measured in 5- to 18-year-old Chinese students using a NIDEK autorefractor before and after administration of 0.5% tropicamide. Spherical equivalent (SER) in diopters (D) was calculated as sphere plus half cylinder. A multivariable prediction model for cycloplegic SER was developed using data from students in Jinyun (n = 1938) and was validated using data from students in Hangzhou (n = 1498). The performance of the prediction model was evaluated using R², mean difference between predicted and measured cycloplegic SER, and sensitivity and specificity for predicting myopia (cycloplegic SER ≤ −0.5 D).

Results

Among 3436 students (mean age, 9.7 years; 51% female), the mean (SD) noncycloplegic and cycloplegic SER values were −1.12 (1.97) D and −0.20 (2.19) D, respectively. The prediction model that included demographics, noncycloplegic SER, axial length/corneal curvature radius ratio, uncorrected visual acuity (UCVA), and intraocular pressure predicted cycloplegic SER with R² of 0.93 in the development dataset and 0.92 in the validation dataset. The mean (SD) differences between predicted and measured cycloplegic SER were 0.0 (0.55) D in the development dataset and 0.06 (0.64) D in the validation dataset. In both the development and validation datasets, the combination of predicted SER and UCVA yielded high sensitivity (91.4% and 91.9%, respectively) and specificity (95.0% and 90.1%, respectively) for detecting myopia.

Conclusions

Cycloplegic refractive error can be predicted using measurements obtained under noncycloplegic conditions. The prediction model could potentially be used to correct the myopia prevalence in epidemiological studies in which administering cycloplegic agent on all participants is not feasible.

Translational Relevance

The prediction model may provide a tool for correcting the overestimation of myopia from noncycloplegic refractive error in future epidemiological studies in which administering cycloplegic agent on all participants is not feasible.

Association of Corneal Biomechanics Properties with Myopia in a Child and a Parent Cohort: Hong Kong Children Eye Study

Associations between corneal biomechanics, axial elongation and myopia are important but previous results are conflicting. Our population-based study aimed to investigate factors associated with corneal biomechanics, and their relationships with myopia in children and adults. Data from 3643 children and 1994 parents showed that children had smaller deformation amplitudes (DA) than parents (p < 0.001). A larger DA was significantly associated with elongated axial length (AL; children: ß = 0.011; adults: ß = 0.0013), higher corneal curvature (children: ß = 0.0086; adults: ß = 0.0096), older age (children: ß = 0.010; adults: ß = 0.0013), and lower intraocular pressure (IOP; children: ß = −0.029; adults: ß = −0.031) in both cohorts. The coefficient of age for DA in children was larger than in adults (p < 0.001), indicating that the DA change with age in children is faster than in adults. DA was significantly associated with spherical equivalent (p < 0.001) resulting from its correlation with AL and corneal curvature. In conclusion, the cornea is more deformable in adults than in children, whereas corneal deformation amplitude increases faster with age in children than that in adults, along with AL elongation. Longer AL, steeper corneal curvature, older age and smaller IOP correspond to a more deformable cornea. The association between corneal deformation amplitude and refraction was mediated via AL and corneal curvature.

Effect of Cycloplegia on Refractive Error Measure in Chinese School Students

PURPOSE

To determine differences in cycloplegic vs. non-cycloplegic refractive error and factors associated with these differences in Chinese school students.

METHOD

In this cross-sectional school-based study, refractive error was measured in school students using a NIDEK autorefractor before and after administration of 0.5% tropicamide. Spherical equivalent (SER) in diopters (D) was calculated as sphere plus half cylinder. SER differences before vs. after cycloplegia were evaluated using mean, standard deviation (SD), 95% limits of agreement. Univariable and multivariable regression models were used to determine factors associated with SER differences.

RESULTS

Among 3604 students, 3450 (95.7%) provided data for analysis. Mean age (SD) was 9.7 (3.6) years. The mean SER (SD) was -1.12 (1.97) D before cycloplegia, and -0.20 (2.19) D after cycloplegia, with a mean difference of 0.92 D (95% limits of agreement: -0.93 to 2.78 D). Among 196 eyes with non-cycloplegic SER -6.0 D or worse (e.g., met high myopia definition), 71.4% had cycloplegic SER -6.0 D or worse, and among 3607 eyes with non-cycloplegic SER -0.5 D or worse (e.g., met myopia definition), 62.1% eyes had cycloplegic SER -0.5 D or worse. Cycloplegic SER was more correlated with axial length than non-cycloplegic SER (Pearson r = 0.82 vs. 0.72, p < .0001). In multivariable analysis, larger SER differences were associated with more hyperopic refractive error and smaller axial length (all p < .0001).

CONCLUSION

Non-cycloplegic refractive error overestimates myopia by approximately one diopter. This overestimation increases with more hyperopic refractive error and smaller axial length. Non-cycloplegic refractive error should not be used for evaluating pediatric myopia.

ABBREVIATIONS

BCVA = best corrected visual acuity; D = diopter; SD = standard deviation; SE = standard error; SER = spherical equivalent; CI = confidence interval.

AI-Model for Identifying Pathologic Myopia Based on Deep Learning Algorithms of Myopic Maculopathy Classification and "Plus" Lesion Detection in Fundus Images

Background: Pathologic myopia (PM) associated with myopic maculopathy (MM) and “Plus” lesions is a major cause of irreversible visual impairment worldwide. Therefore, we aimed to develop a series of deep learning algorithms and artificial intelligence (AI)–models for automatic PM identification, MM classification, and “Plus” lesion detection based on retinal fundus images.

Materials and Methods: Consecutive 37,659 retinal fundus images from 32,419 patients were collected. After excluding 5,649 ungradable images, a total dataset of 32,010 color retinal fundus images was manually graded for training and cross-validation according to the META-PM classification. We also retrospectively recruited 1,000 images from 732 patients from the three other hospitals in Zhejiang Province, serving as the external validation dataset. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, accuracy, and quadratic-weighted kappa score were calculated to evaluate the classification algorithms. The precision, recall, and F1-score were calculated to evaluate the object detection algorithms. The performance of all the algorithms was compared with the experts’ performance. To better understand the algorithms and clarify the direction of optimization, misclassification and visualization heatmap analyses were performed.

Results: In five-fold cross-validation, algorithm I achieved robust performance, with accuracy = 97.36% (95% CI: 0.9697, 0.9775), AUC = 0.995 (95% CI: 0.9933, 0.9967), sensitivity = 93.92% (95% CI: 0.9333, 0.9451), and specificity = 98.19% (95% CI: 0.9787, 0.9852). The macro-AUC, accuracy, and quadratic-weighted kappa were 0.979, 96.74% (95% CI: 0.963, 0.9718), and 0.988 (95% CI: 0.986, 0.990) for algorithm II. Algorithm III achieved an accuracy of 0.9703 to 0.9941 for classifying the “Plus” lesions and an F1-score of 0.6855 to 0.8890 for detecting and localizing lesions. The performance metrics in external validation dataset were comparable to those of the experts and were slightly inferior to those of cross-validation.

Conclusion: Our algorithms and AI-models were confirmed to achieve robust performance in real-world conditions. The application of our algorithms and AI-models has promise for facilitating clinical diagnosis and healthcare screening for PM on a large scale.

Declines in PDE4B activity promote myopia progression through downregulation of scleral collagen expression

Myopia is the most common cause of a visual refractive error worldwide. Cyclic adenosine monophosphate (cAMP)-linked signaling pathways contribute to the regulation of myopia development, and increases in cAMP accumulation promote myopia progression. To pinpoint the underlying mechanisms by which cAMP modulates myopia progression, we performed scleral transcriptome sequencing analysis in form-deprived mice, a well-established model of myopia development. Form deprivation significantly inhibited the expression levels of genes in the cAMP catabolic pathway. Quantitative real-time polymerase chain reaction analysis validated that the gene expression level of phosphodiesterase 4B (PDE4B), a cAMP hydrolase, was downregulated in form-deprived mouse eyes. Under visually unobstructed conditions, loss of PDE4B function in Pde4b-knockout mice increased the myopic shift in refraction, -3.661 ± 1.071 diopters, more than that in the Pde4b-wildtype littermates (P < 0.05). This suggests that downregulation and inhibition of PDE4B gives rise to myopia. In guinea pigs, subconjunctival injection of rolipram, a selective inhibitor of PDE4, led to myopia in normal eyes, and it also enhanced form-deprivation myopia (FDM). Subconjunctival injection of dibutyryl-cyclic adenosine monophosphate, a cAMP analog, induced only a myopic shift in the normal visually unobstructed eyes, but it did not enhance FDM. As myopia developed, axial elongation occurred during scleral remodeling that was correlated with changes in collagen fibril thickness and distribution. The median collagen fibril diameter in the FDM + rolipram group, 55.09 ± 1.83 nm, was thinner than in the FDM + vehicle group, 59.33 ± 2.06 nm (P = 0.011). Thus, inhibition of PDE4 activity with rolipram thinned the collagen fibril diameter relative to the vehicle treatment in form-deprived eyes. Rolipram also inhibited increases in collagen synthesis induced by TGF-β2 in cultured human scleral fibroblasts. The current results further support a role for PDE enzymes such as PDE4B in the regulation of normal refractive development and myopia because either loss or inhibition of PDE4B function increased myopia and FDM development through declines in the scleral collagen fibril diameter.

Acircularity and circularity indexes of the foveal avascular zone in high myopia

This study explored the association between foveal avascular zone (FAZ) parameters and high myopia using optical coherence tomography angiography. We divided 106 eyes of 106 patients into quartiles based on the axial length. The upper quartile was then defined as the high myopia group (n = 27), while the lower quartile was the non-high myopia group (n = 26). The areas and minor axis lengths of superficial and deep FAZ, the perimeters and major axis lengths of deep FAZ were significantly larger in eyes with high myopia than in eyes with non-high myopia (P < 0.05). Inversely, the subfoveal choroidal thickness was significantly thinner in eyes with high myopia than in those with non-high myopia. Linear regression analyses showed that no significant correlation was observed between FAZ areas and acircularity and circularity indexes of FAZ in non-high myopia group. Conversely, FAZ areas strongly correlated with acircularity and circularity indexes of FAZ in high myopia group. We found that an increase in the FAZ area in highly myopic eyes was accompanied by a significant variation in FAZ acircularity and circularity indexes. Further research should address whether these findings are associated with future disease development in highly myopic eyes.

The Effects of Center-near and Center-distance Multifocal Contact Lenses on Peripheral Defocus and Visual Acuity

SIGNIFICANCE

Multifocal contact lenses (MFCLs) are being used clinically for myopia control. Center-distance designs caused myopic changes in defocus across the retina that varied by lens design, whereas the center-near design caused peripheral hyperopic changes. Multifocal lenses caused reductions in low-contrast vision that varied by lens design, affecting visual performance.

PURPOSE

The purpose of this study was to compare changes in defocus with four MFCLs, three center-distance and one center-near.

METHODS

Two cohorts of 25 nonpresbyopic myopic adults were enrolled. The first cohort was fitted with Proclear D and Biofinity D MFCL (center-distance, +2.50 D add), and the second cohort was fitted with NaturalVue MFCL (center-distance) and Clariti 1-Day MFCL (center-near, high add), both in random order. Overrefraction was performed to maximize visual acuity. Cycloplegic autorefraction was performed with each lens and without a lens along the line of sight and at nasal and temporal retinal locations out to 40°. Data were analyzed with repeated-measures ANOVAs with post hoc t tests, when indicated.

RESULTS

Changes in defocus at each location differed between MFCL designs (lens by location; both, P < .001). Clariti 1-Day caused peripheral hyperopic retinal changes (40 and 30° nasal, and 20, 30, and 40° temporal; all, P < .05). NaturalVue MFCL caused myopic changes centrally and hyperopic changes at 40° nasal and 30° temporal (all, P < .05). The remaining center-distance designs caused myopic changes at multiple locations (all, P < .05).

CONCLUSIONS

After overrefraction, the center-near MFCL design caused hyperopic defocus at multiple peripheral locations, which is not hypothesized to slow myopia progression. NaturalVue MFCL caused myopic changes in defocus centrally but hyperopic changes in the far periphery. Biofinity D and Proclear D caused myopic changes in retinal defocus. Further work is warranted to determine whether defocus profile differences between the center-distance designs influence any slowing of myopia progression.

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.

Macular Vessel Density Changes in Young Adults With High Myopia: A Longitudinal Study

Background: To characterize the longitudinal changes of macular vessel density in young adults and its associated factors.

Methods: The right eyes of 309 participants (75 high myopic, 194 mild-to-moderate myopic, and 40 healthy) were followed up for 21 months. OCTA images were acquired at two visits using follow-up scans. Macular vessel density was calculated globally and in the nine early treatment diabetic retinopathy study (ETDRS) subfields of the macula superficial layer.

Results: The macular vessel density significantly decreased in young myopes after a 21-month follow up (p < 0.05), with variations among sectors. Compared with healthy eyes, HM group exhibited a faster reduction in global macular vessel density (p = 0.0307) as well as in sectors of inner-inferior (II), inner-temporal (IT), and outer-temporal (OT) (all p < 0.05). Multivariate regression analysis showed that longer baseline axial length (AL) was significantly associated with larger reduction of macular vessel density in the inner-inferior, inner-temporal and outer-temporal sectors (all p < 0.05).

Conclusions: Compared with emmetropes, high myopes presented greater loss of macular vessel density over time in global and in the inner-inferior, inner-temporal and outer-temporal sectors. A longer baseline AL was associated with larger changes of macular vessel density in the inner-inferior, inner-temporal and outer-temporal sectors.

Optic nerve tortuosity and displacements during horizontal eye movements in healthy and highly myopic subjects

AIMS

(1) To assess the morphology and 3-dimensional (3D) displacements of the eye globe and optic nerve (ON) in adduction/abduction using MRI. (2) To assess differences between healthy emmetropic and highly myopic (HM) subjects.

METHODS

MRI volumes of both eyes from 18 controls and 20 HM subjects in primary gaze, abduction and adduction (15°) were postprocessed. All ONs were manually segmented and fitted to a 3D curve to assess ON tortuosity. ON displacements were evaluated in four quasicoronal planes which were perpendicular to the ON in primary gaze and were 3 mm apart.

RESULTS

Axial length was higher in the HM group (28.62±2.60 vs 22.84±0.89 mm; p<0.0001). Adjusted ON tortuosities (ie, ON tortuosities estimated before myopia onset) were lower in HM eyes (0.9063±0.0591) versus controls (1.0152±0.02981) in primary gaze, adduction (0.9023±0.05538 vs 1.0137±0.0299) and abduction (0.9100±0.0594 vs 1.0182±0.0316); p<0.0001 for all cases. In all eyes, ON displacements in adduction were significantly different from those in abduction in the naso-temporal direction (p<0.0001 in all planes) but not in the supero-inferior direction. ON displacements in the posterior segments of the ON were smaller in the HM group in both gaze directions and were larger in the anterior-most ON segment in adduction only.

CONCLUSION

The adjusted tortuosity of the ON was significantly lower in HM eyes, suggesting that eyes destined towards HM exhibited higher ON traction forces during eye movements before the onset of myopia. Our ON metrics may be valuable to explore a potential link between eye movements and axial elongation.

Review on current concepts of myopia and its control strategies

Myopia poses a significant burden on the healthcare system, economy and quality of life. It is an emerging global public health challenge and requires interventions to delay or stop onset and progression. With changing times and evidence, the concepts of myopia are changing along with the treatment and control strategies. Behavioural modifications including increased outdoors time and reduced near work, optical and pharmaceutical management options are reviewed. This paper presents a current overview on the concepts of myopia, and is expected to summarize updates on myopia control methods.

Orthokeratology lens-related Acanthamoeba keratitis: case report and analytical review

Acanthamoeba keratitis (AK) is a rare but severe ocular infection with a significant risk of vision loss. Contact lens use is the main risk factor for AK. The orthokeratology (OK) lens, a specially designed contact lens, has been used worldwide as an effective method of myopia control. However, the OK lens is associated with an increased risk of Acanthamoeba infection. Many primary practitioners are concerned about this infection because of its relative rarity, the lack of promising therapeutic medications, and the need for referral. We herein report two cases of AK associated with OK lenses, present a systematic review of such cases, and discuss the possible reasons for the higher incidence rate of this infection in patients who wear OK lenses. We combined the clinical knowledge and skills of corneal specialists and lens experts with the sole objective of addressing these OK lens-related AK cases. We found that the most common risk factors were rinsing the lenses or lens cases with tap water. Prompt and accurate diagnosis along with adequate amoebicidal treatment are essential to ensure desirable outcomes for OK lens wearers who develop AK. Appropriate OK lens parameters and regular checkups are also important.

Quantitative analysis with volume rendering of pathological myopic eyes by high-resolution three-dimensional magnetic resonance imaging

Discovering a relationship between axial length and vitreous volume would be helpful since the axial length is easier to measure than magnetic resonance imaging (MRI) parameters. This study aimed to analyze the topography of human eyes with pathological myopia through volume rendering images by high-resolution 3D-MRI and to establish a model to estimate the vitreous volume.This was a retrospective, non-randomized, controlled study of patients evaluated at Tongren Hospital from July 7, 2007 to December 12, 2018. The controls were emmetropic volunteers. All participants underwent ophthalmic examinations. Axial length was measured with an IOL Master. High-resolution 3D MRI and volume rendering was utilized for all the eyes. Logistic regression was used to establish a model to predict the vitreous volume.A total of 280 emmetropic eyes and 290 eyes with pathological myopia were included. Males represented 60.7% and 65.5% of the individuals. The mean axial lengths of those two groups were 23.1 ± 0.8 mm (95%CI: 22.7-23.4 mm) and 28.3 ± 2.2 mm (95%CI: 27.5-29.2 mm), respectively (P < .001). The regression model in the pathological myopic group for calculating the vitreous volume according to the axial length was: Vitreous volume = 546.27 × axial length - 6977.12. The regression model in the emmetropic group for calculating the vitreous volume according to the axial length was: Vitreous volume = 458.35 × axial length - 6331.14 (R = 0.360, P = .001).Elongation of the axial length is involved in eyeball enlargement in pathological myopic eyes. Measurement of the axial length could be recommended for the estimation of the vitreous volume during vitrectomy if vitreous cavity filling is needed.

Effect of Femtosecond Laser in Situ Keratomileusis on the Choriocapillaris Perfusion and Choroidal Thickness in Myopic Patients

PURPOSE

To investigate changes in choriocapillaris vascular density (CCD) and choroidal thickness (CT) after femtosecond laser in situ keratomileusis (FS-LASIK) in myopic patients.

METHODS

Prospective and observational self-control study. We enrolled 41 myopic patients (41 right eyes), without other ophthalmic or systemic diseases who were eligible and about to FS-LASIK surgery. The CCD was measured in the central 1-mm-diameter circle region of the macular fovea (CCD1) and the 1- to 3-mm ring-like region of the fovea (CCD1-3). The CT was measured at the fovea and at distances of 0.5 and 2.5 mm for the following: nasal, temporal, superior, and inferior to the fovea. Both were measured by optical coherence tomography angiography (OCTA) preoperatively as the baseline and at 1 day, 1 week, 1 month, and 3 months postoperatively.

RESULTS

CCD1 and CCD1-3 were significantly lower postoperatively compared with baseline. When the trough was reached, CCD1 declined by 1.51%, and CCD1-3 declined by 1.00% at 1 day postoperatively. However, then they increased with time. CCD1 recovered to baseline at 1 month postoperatively, while CCD1-3 was still lower at the end of follow-up. In addition, the CT was significantly thicker postoperatively and recovered to the baseline at 3 months postoperatively. There was no obvious correlation between CCD, CT, and other parameters.

CONCLUSIONS

The CCD decreased while the CT increased following FS-LASIK in myopic patients. However, these changes may be a temporary stress response rather than real irreversible injury to the choroid.

Independent Influence of Parental Myopia on Childhood Myopia in a Dose-Related Manner in 2,055 Trios: The Hong Kong Children Eye Study

PURPOSE

To determine the effects on childhood myopia of parental myopia, parental education, children's outdoor time, and children's near work.

DESIGN

Population-based cross-sectional study.

METHODS

A total of 6,155 subjects in 2,055 family trios (1 child and both parents). Cycloplegic autorefraction was measured for children and noncycloplegic autorefraction for parents. Parental education, children's outdoor time, and near work were collected by questionnaires. Children were categorized into 10 groups based on parental myopia levels. Associations of the above factors with myopia were evaluated by regression analyses. The areas under the receiver operating characteristic curve (AUROCs) for myopia were evaluated.

RESULTS

Mild parental myopia did not increase childhood myopia's risk, but the risk was 11.22-folds when both parents were highly myopic. Higher parental education (Father: OR 1.08, P = .046; Mother: OR 1.11, P = .001) and more reading time of children were risk factors (OR 1.21, P = .044). Reduced odds of myopia were associated with more time spent on outdoor activities (OR 0.78, P = .017). Notably, all these factors became insignificant after adjustment, except for parental myopia. Children with more severe parental myopia spent more time on reading, but less on electronic devices. Parental myopic status alone accounted for 11.82% of myopia variation in children. With age and parental myopia, the AUROC for myopia was 0.731.

CONCLUSIONS

Among parental and environmental factors, parental myopia confers, in a dose-related manner, the strongest independent effect on childhood myopia. Therefore children with high risk of myopia can be identified for early prevention, based on parental myopia data.

"Macular sink hole" with intrachoroidal cavitation in a case of pathological myopia

Intrachoroidal cavitation (ICC) is a morphological feature outlined by optical coherence tomography and is characterized by presence of a hyporeflective space beneath the unaltered retinal pigment epithelium. It can be peripapillary or macular in location. Macular ICCs are reported in both myopic and non-myopic eyes. We report a case of full thickness macular hole with retinal incarceration into the macular ICC in a patient with pathological myopia. The term “Peripapillary sink hole” has been described in the literature. We propose the use of term “Macular sink hole” for our case owing to similar findings in the macula.

Slowing the Progression of Myopia in Children with the MiSight Contact Lens: A Narrative Review of the Evidence

Myopia has become a major public health problem in the world due to the increase in its prevalence in the past few decades and due to sight-threatening pathologies associated with high myopia such as cataracts, glaucoma and especially myopic maculopathy. This article is a narrative review of the evidence that currently exists on a contact lenses (CLs) specifically designed to correct myopia and to slow its progression. To contextualise the topic we discuss the different classifications and definitions that have been used for myopia, the current burden of being myopic, and current treatment options to prevent and control its progression. There is evidence that exposure to sunlight reduces the risk of myopia onset and pharmacological treatment with atropine has been shown to be the most effective therapy for controlling its progression, followed by optical interventions such as CL fitting (orthokeratology or CLs specific for myopia control) designed to decrease retinal peripheral hyperopic defocus that seems to be the theory that suggests that axial elongation is driven by this defocus and explains why the eye continues to grow abnormally after emmetropisation and generates myopia. We will especially focus on MiSight CLs. MiSight is a daily replacement soft contact lens that has been clinically proven and approved by the US Food and Drug Administration (FDA) to control the progression of myopia in children. We analyse the optical design of MiSight CLs, as well as the results of the different efficacy and safety studies that led to the approval of the lens by the FDA. We also expose current knowledge gaps, limitations and future directions.

High prevalence of myopia in children and their parents in Hong Kong Chinese Population: the Hong Kong Children Eye Study

PURPOSE

To determine the myopia prevalence in Hong Kong Chinese children and their parents.

METHODS

It was a population-based cross-sectional study. A total of 4257 children aged 6-8 years, and 5880 parents were recruited in the Hong Kong Children Eye Study. Cycloplegic autorefraction was measured for children; and non-cycloplegic autorefraction for parents. Parental educational level, children's outdoor time, and near work were collected by validated questionnaires.

RESULTS

In children aged 6-8 years, 25.0% were myopic, and among them, 12.7% for the 6-year-olds, 24.4% for the 7-year-olds and 36.1% for the 8-year-old. About 0.7% of children aged 8 years were high myopia. In all age groups, boys (their myopia rate: 13.9% at 6 years, 26.7% at 7 years, and 38.3% at 8 years) were more myopic than girls (11.3% at 6 years, 22.0% at 7 years, 33.4% at 8 years). Among parents, 72.2% were myopic (mother, 73.2%; father, 70.7%) and 13.5% high myopia (mother, 12.8%; father, 14.5%). It was observed that prevalence decreased with ages and increased with education level.

CONCLUSION

There is a strikingly high prevalence of myopia in Hong Kong children aged 6-8, much higher than that of other regions of China. Of note, the prevalence of children was similar to that in 15 years ago. Furthermore, the myopia prevalence of parents is high, and it had already increased in this cohort. Prevention of childhood myopia is important, likewise for visual complications from high myopia in adults.

Correlation between changes in intraocular pressure and refractive error indices post Cataract Surgery

Objective:

To evaluate the correlation between refractive errors and change in intraocular pressure in patients undergoing cataract surgery.

Methods:

This interventional retrospective case study was carried out from September 2018 to April 2019 at Bodla Eye Care and Multan Medical and Dental College, Multan. A total of 127 eyes were recruited in the study among which six were excluded. Out of remaining 121, 53 eyes were emmetropes, 41 were mild myopes and 27 were high myopes. Single surgeon performed the procedure. Pre-operative investigations of IOP and refractive error were done by goldmann tonometry and auto refractometry. IOP was reviewed at day 1, 7, 14 and 28 post cataract surgeries.

Results:

Out of 121 eyes, 53 eyes were emmetropes, 41 were mild myopes and 27 were high myopes, who underwent phacoemulsification. There was an elevation of 2-3mm Hg at Day-1, in emmetropes and mild myopes, and further on, a constant drop was noticed on follow ups. In high myopes a significant fluctuation of IOP was noted in first fourteen days followed by an unremarkable gradual decline afterwards.

Conclusion:

Cataract surgery helps lowering the IOP in patients with refractive errors. Mild myopic and emmetropic patients showed a linear swift pattern while high myopes presented instable and gradual reduction in IOP. A total decrease of 1-2mm Hg was seen at the end of the study depicting that relation between IOP and cataract surgery is insignificant.

Morphologic and biochemical changes in the retina and sclera induced by form deprivation high myopia in guinea pigs

BACKGROUND

To study the morphologic and biochemical changes in the retina and sclera induced by form deprivation high myopia (FDHM) in guinea pigs and explore the possible mechanisms of FDHM formation.

METHODS

Forty 3-week-old guinea pigs were randomized into the blank control (Group I, 20 cases) and model groups (20 cases). In the model group, the right eyes of the guinea pigs were sutured for 8 weeks to induce FDHM (Group II) and the left eyes were considered a self-control group (Group III). The refractive errors were measured with retinoscopy. The anterior chamber depth (AC), lens thickness (L), vitreous chamber depth (V) and axial length (AL) were measured using ultrasonometry A. Retinal and scleral morphology and ultrastructural features were observed with light and electron microscopy. The malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in the retina and sclera were detected with a chemical colorimetric assay.

RESULTS

After 8 weeks of stitching, the refractive errors of Group II changed from (+ 3.59 ± 0.33) D to (- 7.96 ± 0.55) D, and these values were significantly higher than those of Group I (+ 0.89 ± 0.32) D and Group III (- 0.55 ± 0.49) D (P < 0.05). The vitreous chamber depth (4.12 ± 0.13) mm and axial length (8.93 ± 0.22) mm of Group II were significantly longer than those of Group I [(3.71 ± 0.23) mm and (7.95 ± 0.37) mm, respectively] and Group III [(3.93 ± 0.04) mm and (8.01 ± 0.15) mm, respectively] (P < 0.05). With the prolongation of form deprivation (FD), the retina and scleral tissues showed thinning, the ganglion cell and inner and outer nuclear layers of the retina became decreased, and the arrangement was disordered. In Group II, the SOD activity was significantly lower than that in Group I and Group III; the MDA content was significantly higher than that in Group I and Group III. The differences were statistically significant (P < 0.05).

CONCLUSIONS

These findings suggested that in the FDHM guinea pigs model, the refractive errors, the vitreous chamber depth, and axial length increased significantly with prolongation of monocular FD time, and morphological structural changes in the retina and sclera were observed. Oxygen free radicals might participate in the formation of FDHM.

Influence of the foveal curvature on myopic macular complications

In this cross-sectional study, we investigated whether a foveal curvature affects the development of two major myopic macular complications, myopic traction maculopathy (MTM) and myopic choroidal neovascularization (mCNV). In high myopic eyes (axial length ≥ 26.5 mm, refractive error ≤ −6 diopters) with posterior staphyloma, three different parameters of foveal curvature (staphyloma height, coefficient a, and curvature index) calculated based on the retinal pigment epithelium hyperreflective line in spectral domain optical coherence tomography image were compared among the MTM (72 eyes), mCNV (58 eyes), and control (69 eyes) group. The three curvature parameters showed a significant correlation with each other (all P’s < 0.001). The axial length, refractive error, and staphyloma types were comparable among the groups, but the means of all three curvature parameters were significantly greater in the MTM group compared to the mCNV and control groups (all P’s < 0.001). Furthermore, the curvature parameters had a significant correlation with myopic severity in the MTM group, but not in the other groups. These results suggest that a steeper change of foveal curvature plays a role in the development of MTM but not mCNV in high myopes.

Anterior and Posterior Segment Manifestations of Pathological Myopia: A Clinical Study from Turkish Aegean Region

Background and Objective:

Myopia is one of the most prevalent vision conditions caused by a mismatch between the refractive power and axial length of the eyeball. High myopia may have a degenerative disorder, including cornea, sclera, choroid, optic disc, vitreous, macula, and peripheral retina. Although there are few studies regarding clinical features of pathological myopia, especially in the far-eastern countries where myopia is common, but are no comprehensive data in our region. This study was aimed to demonstrate both anterior and posterior ocular segment manifestations of pathological myopia.

Methods:

One hundred forty eyes of 82 patients who met the pathological myopia criteria were enrolled in this prospective study. Measurements of Central Corneal Thickness (CCT), endothelial cell parameters, Anterior Chamber Depth (ACD), Axial Length (AL) and Subfoveal Choroidal Thickness (SFCT) were performed in all patients. Presence of posterior segment pathologies such as peripapillary atrophy, tilted disc, Lacquer's crack, foveoschisis, myopic maculopathy, Choroidal Neovascularization (CNV), and peripheral retinal degeneration was recorded.

Results:

The mean age was 54.1 ± 14.2 years. 43 (52.4%) of the patients were female. One hundred patients (71.4%) were phakic and 40 (28.6%) were pseudophakic. The mean CCT, corneal endothelial cell density, ACD, AL, and SFCT were 548.91 ± 43.44 µm, 2335.89 ± 374.38 cells/mm2, 3.93 ± 0.79 mm, 28.75 ± 2.20 mm, and 94.56 ± 73.11 µm, respectively. Tilted disc, peripapillary atrophy and posterior staphyloma were detected in 89 (63.6%), 119 (85%) and 78 (55.7%) eyes, respectively. Normal fundus, tessellated fundus, diffuse chorioretinal atrophy, focal chorioretinal atrophy and macular atrophy were seen in 13 (9.3%), 59 (42%), 26 (18.6%), 14 (10%), and 28 (20%) eyes, respectively. Lacquer crack, CNV, and Fuchs spot were observed in 11 (7.9%), 39 (27.9%), and 47 (33.6%) eyes, respectively.

Conclusion:

This study reported clinical characteristics of eyes with pathological myopia in a retina specialty clinic at a tertiary referral center from the Turkish Aegean Region. Pathological myopia may affect both anterior and posterior ocular segments. However, posterior segment manifestations may be associated with lesions that threaten vision. Therefore, periodic follow-up in patients with pathological myopia is critical.

The Increasing Burden of Myopia in Israel among Young Adults over a Generation: Analysis of Predisposing Factors

PURPOSE

To determine the trends in prevalence of myopia in Israeli young adults over approximately a generation, as well as associated factors and variation in the impact of these factors on myopia prevalence in this region over time.

DESIGN

Retrospective, cross-sectional study.

PARTICIPANTS

One hundred four thousand six hundred eighty-nine consecutive persons 16 to 19 years of age born between 1971 and 1994 who had not yet enlisted in the Israeli Army but had completed the medical profiling process.

METHODS

Using data collected at a north Israel recruitment center, the prevalence of myopia over time was estimated, and a polynomial regression analysis was performed to assess significance of nonlinear trends. Associations of demographic and socioeconomic factors with myopia were assessed, and trends over time were analyzed using a factorial logistic regression.

MAIN OUTCOME MEASURES

The primary outcome measure was factors associated with the prevalence of myopia over time. The secondary outcome measure was a description of the change in prevalence of myopia over time.

RESULTS

The prevalence of myopia increased 1.284-fold over 24 years from 20.4% among participants born between 1971 and 1982 to 26.2% among participants born between 1983 and 1994. A quite similar increase was observed among males (from 17.9% to 22.7%, respectively) and females (from 23.9% to 30.8%, respectively). The factors found to be associated with myopia were as follows: more recent date of birth, female gender, more years of education, being the eldest child, non-Israeli ethnic origin, and urban residence. However, there were significant trends over time in the effects of some of these factors, most notably an attenuation of the difference between participants of different religions in the recent birth-years period. Most of these associations and trends were observed in both males and females separately, with some gender-specific variations. Immigrants from Ethiopia who were raised in Israel were highly more likely to demonstrate myopia than those who arrived at an older age.

CONCLUSIONS

This study demonstrated an increase in the prevalence of myopia and the possible associations of urbanization- and higher education-related factors among several subpopulations and the risk for myopia developing.

Effect of Age and Myopia on Retinal Microvasculature

BACKGROUND AND OBJECTIVE

To investigate the effect of age and refractive error on changes in the retinal microvascular network.

PATIENTS AND METHODS

Subjects were recruited from the Doheny Eye Institute. Refractive error and axial length were measured. High myopia was defined as refractive error greater than -6 diopters (D). Optical coherence tomography angiography (OCTA) imaging was performed and images were analyzed using fractal analysis. Primary outcomes were superficial capillary plexus (SCP) vessel density, deep capillary plexus (DCP) vessel density, and foveal avascular zone (FAZ) area.

RESULTS

One hundred thirty-eight eyes of 69 subjects were included. Twenty-eight (41%) subjects were male and 41 (59%) subjects were female. Mean age was 42.81 years ± 19.91 years (range: 8 years to 87 years). Mean refractive error was -1.74 D ± 3.18 D (range: -15.78 D to 4.25 D), and mean axial length (AL) was 24.29 mm ± 1.35 mm (range: 21.73 mm to 28.32 mm). SCP and DCP vessel densities were negatively correlated to age (r = -0.22, P = .011; and r = -0.49, P < .001). Controlling for age, patients with high myopia and longer AL had decreased SCP density (P = .021 and P = .027, respectively), but no difference in DCP vessel density was observed (P = .065 and P = .058, respectively). FAZ area was not significantly correlated to age, gender, refraction, or AL.

CONCLUSIONS

SCP and DCP vessel densities decreased with age. In addition, SCP density but not DCP vessel density was reduced in eyes with high myopia and longer AL. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:925-931.].

Changes of intraocular pressure after cataract surgery in myopic and emmetropic patients

To investigate the intraocular pressure (IOP) changes after cataract surgery, and its relationship with refractive conditions.IOP after phacoemulsification with intraocular lens (IOL) implantation was retrospectively reviewed. Patients were classified into 3 groups by refractive conditions: emmetropia, mild to moderate myopia, and high myopia. Basic information was collected including age, sex, place of IOL, and operating surgeon, with IOP and refractive conditions measured before surgery, and 1, 7, 30, and 90 days after surgery.The study comprised 353 eyes from 353 patients, of which 175 were emmetropia, 130 were mild to moderate myopia, and 48 were high myopia. A lower IOP than baseline was observed at 7, 30, and 90 days after surgery in emmetropic and mild to moderate myopia, while in high myopia, IOP was instable from 1 to 30 days, and reduced only in 90 days after surgery. Changes of IOP was more significant from 1 to 7 days in emmetropic and mild to moderate myopic patients, but from 30 to 90 days in high myopia. Patients over 75 showed a lower IOP at each follow-up than patients younger and female showed a higher baseline IOP than male. Different surgeons might influence the IOP fluctuation at first 90 days but not the final IOP.All patients with different refractive conditions showed a remarkably lower IOP at 90 days after cataract surgery. However, high myopia lowered the speed of IOP reduction, which might be explained by the anatomical changes of eye structure.

FULL-THICKNESS MACULAR HOLE WITH MACULAR INTRACHOROIDAL CAVITATION IN A PATIENT WITH PATHOLOGIC MYOPIA

PURPOSE

To describe a full-thickness macular hole (MH) opening to macular intrachoroidal cavitation in a patient with pathologic myopia.

METHODS

Full ophthalmologic examination, fundus camera (Topcon TRC; Topcon Co, Tokyo, Japan), optical coherence tomography (RetinaScan Advanced RS-3000; NIDEK, Gamagori, Japan) imaging, and cataract surgery.

RESULTS

A 61-year-old woman admitted with decreased vision in the left eye. Visual acuity was counting fingers from 30 cm. Anterior segment examination showed advanced cataract. Fundus examination revealed pathologic myopia. There was full-thickness MH opening to macular intrachoroidal cavitation in contact with the anterior surface of the sclera subfoveally. Except for the communicating part of MH and macular intrachoroidal cavitation, outer retina, ellipsoid zone, and retinal pigment epithelium were intact. Choroid was intact except for a small part at subfoveal area. The patient received an uncomplicated cataract surgery. Visual acuity improved to 5/10. Because she was satisfied, MH surgery was postponed to a later date.

CONCLUSION

Full-thickness MH may occur within the area of macular intrachoroidal cavitation in pathologic myopia.

Implantation of a Multifocal Toric Intraocular Lens after Radial Keratotomy and Cross-Linking with Hyperopia and Astigmatism Residues: A Case Report

Radial keratotomy is a refractive surgical technique, widely used in the 80s and early 90s to correct myopia and astigmatism, but now overcome by more recent laser techniques. Important consequences, often in patients with more than 45 years of age, are progressive hyperopic shift and/or an increase in corneal astigmatism, whose main cause seems to be an increase in the curvature radius of the central portion of the cornea. This seems to be due to radial keratotomy incisions – with the consequent need for cross-linking – intraocular pressure, and corneal biomechanical parameters. The authors propose phacoemulsification with a customized multifocal toric intraocular lens implantation to correct the induced shift and hyperopic astigmatism. A decent postoperative visual acuity was observed with good patient satisfaction. A specific protocol must be applied to optimize the correct diagnosis, presurgical evaluation and postsurgical outcomes that are to be maintained over time, without regressions.

The opportunistic screening of refractive errors in school-going children by pediatrician using enhanced Brückner test

Aim:

The aim of this study was to compare the results of enhanced Brückner test (EBT) performed by a pediatrician and an experienced pediatric ophthalmologist.

Subjects and Methods:

In this prospective double-masked cohort study, a pediatrician and a pediatric ophthalmologist performed the EBT in a classroom of a school in semi-dark lighting condition using a direct ophthalmoscope. The results of the test were compared using 2 × 2 Bayesian table and kappa statistics. The findings of the pediatric ophthalmologists were considered gold standard.

Results:

Two hundred and thirty-six eyes of 118 subjects, mean age 6.8 ± 0.5 years (range, 5.4–7.8 years), were examined. The time taken to complete this test was <10 s per subject. The ophthalmologist identified 59 eyes as ametropic (12 hyperopic and 47 myopic eyes) and 177 as emmetropic compared to 61 eyes as ametropic and 175 emmetropic by pediatrician. The prevalence of the test positive was 25.9%. The sensitivity of the pediatrician was 90.2%, specificity was 97.7%, predictive value of the positive test was 93.2%, and predictive value of the negative test was 96.6%. The clinical agreement (kappa) between the pediatric ophthalmologist and the pediatrician was 0.9.

Conclusion:

The results of the EBT performed by pediatrician were comparable to that of an experienced pediatric ophthalmologist. Opportunistic screening of refractive errors using EBT by a pediatrician can be an important approach in the detection of ametropia in children.