Prevalence of eye diseases and causes of visual impairment in school-aged children in Western China

Cost-effectiveness of screening for amblyopia among kindergarten children in China

Objective

Current cost-effectiveness analyses of amblyopia screening are mainly from western countries. It remains unclear whether it is cost-effective to implement a preschool amblyopia screening programme in China. Our study aimed to evaluate the cost-effectiveness of a hypothetical kindergarten-based amblyopia screening versus non-screening among 3-year-old children.

Methods

We developed a decision tree combined with a Markov model to compare the cost and effectiveness of screening versus non-screening for 3-year-old children from a third-party payment perspective. The primary outcomes were quality-adjusted life years (QALYs) and the incremental cost-effectiveness ratio (ICER). Costs were obtained from expert opinions in different regions of China. Transition probabilities and health utilities were mainly based on published literature and open sources. Sensitivity analyses were performed to assess the impact of parameters' uncertainty on results.

Results

Base-case analysis demonstrated that the ICER of screening versus non-screening was $17,466/QALY, well below the WTP threshold ($38,223/QALY) for China. One-way sensitivity analysis showed that the prevalence of amblyopia, the transition probability per year from untreated amblyopia to healthy, and the discount rate were the top three factors. The likelihood of cost-effectiveness of screening compared with non-screening was 92.56%, according to probabilistic sensitivity analysis. Scenario analysis also indicated that ICER was lower than the WTP threshold even if the time horizon was shortened or the screening was delayed to the age of 4 or 5.

Conclusions

Amblyopia screening could be considered a cost-effective strategy compared to non-screening for 3-year-old children in China. Screening for children at the age of 4 or 5 may even yield better results.

Epidemiology of eye diseases: outcomes from a free provincial eye clinic in Papua New Guinea

Aim

To ascertain the prevalence and pattern of eye problems in Madang Province, Papua New Guinea.

Materials and methods

A six-month retrospective study was performed at Madang Provincial Hospital Eye Clinic. Convenience sampling was used in this study and all patient records from January to June 2020 were included. Data was extracted using Microsoft Excel and the data included gender, age, occupation, district where the patient lived, presenting visual acuity, and diagnosis. It was then analyzed using International Business Machines Corporation's Statistical Package for the Social Sciences version 26. A p-value of ≤0.05 was considered statistically significant.

Results

A total of 1,715 patients received services at the eye clinic between January and June 2020, and 1,664 were included in this study. The mean age of the patients was 39.3 ± 20.3 years. There were slightly more males (50.4%) than females. The overall leading ocular morbidities were corneal ulcers and keratitis (20.7%), refractive errors (17.4%), and cataracts (16.8%). More than half of the patients (56.2%) were either visually impaired or blind. Nearly half of the patients (41.8%) traveled long distances to seek services at the eye clinic. There was a significant association between demographic characteristics, diagnosis, and level of visual impairment.

Conclusion

There is a high prevalence of potential causes of visual impairment and blindness in Madang Province and these conditions affect all age groups and genders. It is essential to increase accessibility to eye care services in the country.

EFFECTIVENESS OF TEACHERS IN THE DETECTION OF EYE DISORDERS AMONG PRIMARY SCHOOL CHILDREN IN ABAKALIKI METROPOLIS, EBONYI STATE NIGERIA

Background

Schoolteachers who have knowledge on eye diseases can detect early children with eye disorders and refer them promptly to an eye specialist. The aim of this study is to assess the effectiveness of teachers in a vision screening program for primary school children in Abakaliki.

Methods

This descriptive cross-sectional study was conducted among 20 randomly selected primary schoolteachers in Abakaliki to screen for vision abnormalities and detect eye problems among 350 children from 5 schools. Teachers participated in a 2-day training using a modified training algorithm on vision screening using a Snellen's chart and in the identification of common ocular abnormalities. Data was analysed using IBM SPSS version 26 statistical program and a p-value of <0.05 at 95% confidence level was statistically significant.

Results

A total of 379 children were enrolled into the study however, 350 (92.3%) children participated in the study. School teachers correctly identified 283 (92.8%) children who had normal vision and 33(73.3%) who had impaired vision. Overall 60 (17.1%) children with perceived eye defects were referred to the ophthalmologist for re-examination. Refractive error and allergic conjunctivitis were the most common eye problems identified and children with refractive error and other ocular morbidity were referred to the base hospital.

Conclusion

Teachers are a valuable resource in the detection of eye disorders among school children. Their effectiveness can be further enhanced by regular training, and collaboration with eye care professionals. Addressing these limitations through policy implementation can lead to better eye health outcomes for school children in Nigeria.

Incidence and distribution of ocular disorders in the first year of life

PURPOSE

To describe the incidence and distribution of eye diseases affecting children in the first year of life in Olmsted County, Minnesota.

METHODS

We conducted a population-based, retrospective medical record review of infants (≤1 year of age) residing in Olmsted County diagnosed with an ocular disorder from January 1, 2005, through December 31, 2014.

RESULTS

A total of 4,223 infants were diagnosed with an ocular disorder, yielding an incidence of 20,242/100,000 births per year, or 1 in 4.9 live births (95% CI, 19,632-20,853). The median age at diagnosis was 3 months, and 2,179 (51.5%) were female. The most common diagnoses included conjunctivitis, in 2,175 (51.5%), nasolacrimal duct obstruction, in 1,432 (33.6%), and pseudostrabismus, in 173 (4.1%). Visual acuity was decreased in one or both eyes in 23 (0.5%) infants because of strabismus in 10 (43.5%) and cerebral visual impairment in 3 (13.0%). A majority of the infants (3,674 [86.9%]) were diagnosed and managed by a primary care provider, and 549 (13.0%) were evaluated and/or managed by an eye care provider.

CONCLUSIONS

Although ocular disorders occurred in 1 in 5 infants in this cohort, most conditions were evaluated and managed by primary care providers. Understanding the incidence and distribution of ocular diseases among infants is useful for planning clinical resources.

Strabismus and Nystagmus in Patients With Pediatric Cataracts: Study Using Insurance Claims Data

PURPOSE

To describe the characteristics and prevalence of strabismus and nystagmus in children diagnosed with cataracts using a national insurance claims database.

DESIGN

Population-based retrospective cohort study.

METHODS

Patients aged <13 years diagnosed with cataracts (traumatic cataracts excluded) and enrolled continuously in their health care program for ≥5 years after their first cataract diagnosis were identified in a retrospective review of 66 million charts in Optum's de-identified Clinformatics Data Mart Database between 2003 and 2015. Patients were categorized based on age of their first diagnosed cataract, and if cataract surgery was performed. Clinical and demographic factors associated with the occurrence of strabismus and nystagmus were evaluated.

RESULTS

Of 1636 children diagnosed with cataract, 434 (26.5%) and 109 (6.7%) were diagnosed with strabismus and nystagmus, respectively. Both strabismus and nystagmus were more common in those who underwent cataract surgery (P < .001) and in patients diagnosed with cataract at ≤12 months of age (P < .001). Survival analysis demonstrated that strabismus and nystagmus may be diagnosed 8 years after the initial cataract diagnosis. Cox proportional hazard regression analyses revealed strabismus was associated with cataract surgery, nystagmus, and the diagnosis with cataract at ≤12 months and cataract surgery at >12 months.

CONCLUSIONS

As strabismus and nystagmus occur more frequently in children diagnosed with cataracts necessitating cataract surgery, regular long-term follow-up is crucial for these children to monitor for the development of strabismus and nystagmus.

The prevalence and county-level socioeconomic correlates of visual impairment and glasses ownership among rural students in Western China

Objectives

Vision health has been a major issue in public health care. The vision problems of children in rural China are of particular concern. Effective policies for children's vision health should consider the heterogeneity of individual health levels and regional differences in healthcare services. This study systematically explored the relationship of student visual impairment and glasses ownership with county-level socioeconomic status (namely, county-level per capita GDP, population density and industrial structure) in rural China.

Methods

The study sample included 99,670 students in grades 4-9 from 445 schools in 13 counties in Shaanxi Province. From 2014 to 2020, students took school-based vision screening tests and completed sociodemographic questionnaires. Multivariate regressions were used for empirical analysis.

Results

The prevalence of visual impairment was 30.4% in the total sample, and the rate of visual impairment in girls (34.3%) was higher than that in boys (27.0%). Among visually impaired students, the rate of glasses ownership was only 39.7%, with girls (40.6%) higher than boys (38.8%). The study also found that the visual impairment was significantly correlated with county-level average income, population density and industrial structure, and the glasses ownership was significantly correlated with population density and industrial structure (all p < 0.001).

Conclusions

The study found that the county-level socioeconomic status was positively and significantly correlated with visual impairment and glasses ownership, respectively. The vision health management services for students should be jointly carried out by the education, medical and public health departments, and additional investment is needed to increase the accessibility and affordability of vision care services, with special focus on poor regions and disadvantaged groups, so as to narrow the gap in vision health services.

Knowledge and Practices of Child Eye Healthcare Among Parents in Aseer Region, Saudi Arabia

BACKGROUND

The majority of causes of childhood blindness are preventable and treatable. There are an estimated 1.4 million blind children worldwide, with roughly three-quarters of them living in developing countries. In most low-income countries, school-age children account for 20%-30% of the total population.

AIM

To evaluate parents' knowledge, attitudes, and practices related to pediatric eye medical services in Saudi Arabia's Aseer region.

METHODOLOGY

A descriptive cross-sectional approach was used targeting all parents in the Aseer region. Data were collected using a structured questionnaire developed by the study investigators. The questionnaire included parents' sociodemographic data and a family history of blindness or visual disability. Parents' awareness regarding pediatric eye care was assessed using relevant items. The parents' practices and attitudes regarding eye care were also assessed within the questionnaire.

RESULTS

The study included 899 parents who replied to the online questionnaire in its entirety. Some 54% of the responding parents were aged 30-50 years, and 51.2% were males. Of the parents, 46.2% had a university-level education, and 48.5% accompanied their children for eye examinations. About 65% of the parents knew about clinics for eye examinations, and 63.3% of them knew that blind children could learn. In total, more than one-third of the parents were aware of pediatric eye care.

CONCLUSIONS AND RECOMMENDATIONS

The study found that parents were aware of pediatric eye health and sought eye care for their children. More effort should be put forth through planned awareness programs to educate parents and assist them in overcoming the fears and barriers that keep them from seeking eye care for their children.

Development and Validation of a Nomogram for Predicting Second Surgery in Patients with Concomitant Esotropia

INTRODUCTION

This study developed and validated a nomogram for predicting the risk of second surgery in patients with concomitant esotropia (CE) based on a cohort in Beijing.

METHODS

In this retrospective cohort study, the inpatient and outpatient medical records of 419 patients with CE who underwent surgery at the Peking University First Hospital between January 1, 2005 and December 31, 2009 were collected. A total of 357 CE cases were included. For those cases 70% were randomly assigned to the training set (n = 234) and 30% to the validation set (n = 123). Demographic and clinical variables were ascertained at hospital admission and discharge and screened using multivariate Cox proportional hazards regression analysis to construct predictive models and generate a 1-, 4-, and 8-year overall survival nomogram. This nomogram provided an estimate of the risk of second surgery in patients with surgically treated CE. Internal validation was conducted using the concordance index (C-index) and calibration curve for the training and validation sets.

RESULTS

Six independent prognostic factors were identified, namely age at surgery, age at onset, amblyopia, deviation angles, surgical amount, and deviation angles 1 week after surgery, and these were entered into the nomogram. The proposed nomogram showed favorable discrimination and accuracy in the training and validation sets. The C-indexes of the training and validation sets were 0.84 (95% CI 0.79-0.89) and 0.80 (95% CI 0.78-0.82), respectively.

CONCLUSIONS

The proposed nomogram can serve as a predictive tool for prognostic evaluation of CE surgery.

Trends in Myopia Development Among Primary and Secondary School Students During the COVID-19 Pandemic: A Large-Scale Cross-Sectional Study

Objectives

To evaluate myopia development among primary and secondary school students during the coronavirus 2019 (COVID-19) pandemic.

Methods

A cross-sectional study was conducted to evaluate the development of myopia among students in Shenzhen, China during the COVID-19 outbreak.

Results

The study included 1,472,957 and 1,573,824 students in 2019 and 2020, respectively. The prevalence of myopia was 46.9 and 50.5% in 2019 and 2020, respectively. The prevalence of myopia among students in the former Shenzhen Special Economic Zone (SEZ) was higher than that in areas outside the former Shenzhen SEZ (2019: 47.0 vs. 43.7%; 2020: 50.5 vs. 47.3%). The prevalence of myopia among girls was higher than that among boys (2019: 50.4 vs. 44.0%; 2020: 54.0 vs. 47.6%). The 50th percentile (P50) of spherical equivalent refraction (SER) in the right eye among girls was lower than that in boys. The prevalence of myopia continued to increase as the grade increased, with the greatest annual increase observed in Grades 2–5 (3.4–3.9%). The P50 of SER in the right eye of students decreased as the grade increased.

Conclusions

The prevalence of myopia among students increased during the COVID-19 pandemic, especially in primary school Grades 2–5.

Prevalence of Pediatric Cataract in Asia: A Systematic Review and Meta-Analysis

Purpose:

To conduct a systematic review and meta-analysis for estimating the prevalence of pediatric cataracts across Asia.

Methods:

A detailed literature search of PubMed, Embase, Web of Science, Cochrane Library, and Google Scholar databases, from 1990 to July 2021, was performed to include all studies reporting the prevalence of cataracts among children. Two researchers performed the literature search and screening of articles independently, and a third researcher critically reviewed the overall search and screening process to ensure the consistency. The JBI Critical Appraisal Checklist for studies reporting prevalence data was used to assess the methodological quality of the included studies.

Results:

Of the 496 identified articles, 35 studies with a sample size of 1,168,814 from 12 Asian countries were included in this analysis. The estimated pooled prevalence of pediatric cataracts in Asian children is 3.78 (95% confidence interval: 2.54–5.26)/10,000 individuals with high heterogeneity (I^[2] = 89.5%). The pooled prevalence by each country per 10,000 was 0.60 in Indonesia, 0.92 in Bangladesh, 1.47 in Iran, 2.01 in Bhutan, 3.45 in Laos, 3.68 in China, 4.27 in Thailand, 4.47 in India, 5.33 in Malaysia, 5.42 in Nepal, 9.34 in Vietnam, and 10.86 in Cambodia.

Conclusions:

This study utilizes existing literature to identify the prevalence of cataracts in Asian children. Moreover, it highlights the need for more epidemiological studies with large sample sizes from other countries in Asia to accurately estimate the burden of disease.

The Global Prevalence of Amblyopia in Children: A Systematic Review and Meta-Analysis

Epidemiological data about the prevalence of amblyopia around the world vary widely among regions and periods. This meta-analysis aimed to determine the global prevalence of amblyopia in children. PubMed, Embase, and the Cochrane Library were searched for prevalence studies published up to 5 November 2021. The outcome was the prevalence of amblyopia, analyzed as pooled estimates with 95% confidence intervals (CI). A total of 97 studies were included, including 4,645,274 children and 7,706 patients with amblyopia. The overall worldwide pooled prevalence of amblyopia was 1.36% (95%CI: 1.27-1.46%). The prevalence of amblyopia was higher in males (1.40%, 95%CI: 1.10-1.70%) than in females (1.24%, 95%CI: 0.94-1.54%) (OR = 0.885, 95%CI: 0.795-0.985, P = 0.025). The results of the meta-regression analysis showed that there were no significant associations between the prevalence of amblyopia and geographical area, publication year, age, sample size, and whether it was carried out in a developed or developing country (all P > 0.05). Begg's test (P = 0.065) and Egger's test (P < 0.001) showed that there was a significant publication bias in the prevalence of amblyopia. In conclusion, amblyopia is a significant vision problem worldwide, and public health strategies of early screening, treatment, and management are important.

Global Prevalence and Causes of Visual Impairment and Blindness in Children: A Systematic Review and Meta-Analysis

Purpose:

To determine the global prevalence and common causes of visual impairment (VI) and blindness in children.

Methods:

In this meta-analysis, a structured search strategy was applied to search electronic databases including PubMed, Scopus, and Web of Science, as well as the list of references in the selected articles to identify all population-based cross-sectional studies that concerned the prevalence of VI and blindness in populations under 20 years of age up to January 2018, regardless of the publication date and language, gender, region of residence, or race. VI was reported based on presenting visual acuity (PVA), uncorrected visual acuity (UCVA), and best corrected visual acuity (BCVA) of equal to 20/60 or worse in the better eye. Blindness was reported as visual acuity worse than 20/400 in the better eye.

Results:

In the present study, 5711 articles were identified, and the final analyses were done on 80 articles including 769,720 people from twenty-eight different countries. The prevalence of VI based on UCVA was 7.26% (95% confidence interval [CI]: 4.34%–10.19%), PVA was 3.82% (95% CI: 2.06%–5.57%), BCVA was 1.67% (95% CI 0.97%–2.37%), and blindness was 0.17% (95% CI: 0.13%–0.21%). Refractive errors were the most common cause of VI in the subjects of selected articles (77.20% [95% CI: 73.40%–81.00%]). The prevalence of amblyopia was 7.60% (95% CI: 05.60%–09.10%) and congenital cataract was 0.60% (95% CI: 0.3%–0.9%).

Conclusion:

Despite differences in the definition of VI and blindness, based on PVA, 3.82%, and based on BCVA, 1.67% of the examined samples suffer from VI.

Prevalence and patterns of childhood ocular morbidity in Kinshasa. A population-based study

Context

Childhood ocular disorders can seriously impact on development and education, future employment opportunities and quality of life, their consequences are especially severe in low resource settings. There is a lack of data on pattern and prevalence of ocular morbidities among children in Democratic Republic of the Congo (DRC).

Objective

The aim of this study was to determine the pattern and magnitude of childhood ocular disorders in children in Kinshasa, the capital city of DRC.

Methods

A population-based cross-sectional study was conducted from July to August 2017. Children aged less than 16 years old were screened by volunteers in households and those with ocular pathologies were examined by two ophthalmologists. Prevalence and pattern of ocular diseases were determined.

Results

A total of 4307 households were visited by the surveyors and 13,197 children were screened. Ocular pathologies were diagnosed among 399 children. Girls represented 50.7% of the children and the mean age ± SD was 9.2 ± 4.1 years. The overall prevalence of ocular morbidity in our population was 3.6% [95% CI 3.3-3.9]. Allergic conjunctivitis was the most frequent pathology (56.2%) followed by refractive errors (27.4%) and strabismus (5%). Age of children was the only risk factor with a significant impact on the frequency of ocular pathology. Forty-five percent of children had never benefited from any treatment, self-medication, and recourse to traditional treatments concerned respectively 18.%, and 2.3% of children.

Conclusion

Childhood ocular morbidity in Kinshasa city was dominated by allergic conjunctivitis and refractive errors. The frequency of these conditions varies depending on the age of the children. Very few parents consult medical staff when their children have ocular problems, ignorance and limited financial resources are the principal barriers to consult.

Prevalence and pattern of refractive error and visual impairment among schoolchildren: the Lhasa childhood eye study

Background

Early and effective ocular screening may help to eliminate treatable eye disorders. The Lhasa Childhood Eye Study (LCES) revealed the particular prevalence of refractive error and visual impairment in grade one schoolchildren (starting age of 6 years old) in Lhasa.

Methods

This is a cross-sectional part of school-based cohort study. One thousand nine hundred forty-three children were enrolled (median age, 6.78 years, range, 5.89 to 10.32). Each child underwent general and ocular examinations, including logarithm of the minimum angle of resolution (logMAR) visual acuity, cycloplegic autorefraction, and slit-lamp biomicroscopy evaluation. Multivariate and correlation analyses were performed to evaluate the association between refractive error with gender and ethnics.

Results

The prevalence of visual impairment (logMAR visual acuity ≥0.3 in the better-seeing eye) of uncorrected, presenting and best-corrected visual acuity (BCVA) was 12.2, 11.7 and 2.7%, respectively. Refractive error presented in 177 (78.0%) out of 227 children with bilateral visual impairment. Myopia (spherical equivalent refractor [SER] ≤ − 0.50 diopter [D] in either eye) was present in 4.7% children when measured after cycloplegic autorefraction. Hyperopia (SER ≥ + 2.00 D) affected 12.1% children. Hyperopia was significantly associated with female gender (P<0.001). Astigmatism (cylinder value ≤ − 0.75 D) was present in 44.8% children. In multivariate regression and correlation analysis, SER had no significant difference between ethnic groups.

Conclusion

The Lhasa Childhood Eye Study is the first school-based cohort study to reveal the prevalence and pattern of refractive error and visual impairment in Lhasa. Effective strategies such as corrective spectacles should be considered to alleviate treatable visual impairment.

The prevalence and correlates of vision impairment and glasses ownership among ethnic minority and Han schoolchildren in rural China

PURPOSE

To determine the prevalence of visual impairment and glasses ownership among Han Chinese and Hui minority junior high school children in Ningxia Hui Autonomous Region, China.

DESIGN

Population-based cross-sectional study.

METHODS

Vision screening was conducted on 20,376 children (age 12-15 years) in all 124 rural junior high schools in Ningxia. Personal and family characteristics, glasses ownership, and academic performance were assessed through a survey questionnaire and standardized mathematics test, respectively.

RESULTS

The prevalence of visual acuity (VA) ≤6/12 in either eye was significantly higher among Han (54.5%) than Hui (45.2%) children (P<0.001), and was significantly positively associated with age, female sex, Han ethnicity, parental outmigration for work, shorter time spent outside during recess, shorter time spent watching television and higher time spent studying. Among children with VA≤6/12 in both eyes, only 56.8% of Han and 41.5% of Hui children had glasses (P<0.001). Glasses ownership was significantly associated with worse vision, greater family wealth, female sex, higher test scores, age, parental outmigration for work, understanding of myopia and glasses, higher time spent studying and Han ethnicity.

CONCLUSION

One of the first of its kind, this report on Han and Hui ethnic schoolchildren confirms a high prevalence of visual impairment among both populations, but slightly higher among the Han. Both groups, especially the Hui, have low rates of glasses ownership. Future interventions and policies designed to improve glasses usage should focus on populations with lower incomes and seek to correct erroneous beliefs about the safety of glasses and efficacy of traditional eye exercises.

Prevalence and time trends of refractive error in Chinese children: A systematic review and meta-analysis

Background

To investigate the prevalence and time trends of refractive error (RE) among Chinese children under 18 years old.

Methods

PubMed, Embase, Web of Science were searched for articles that estimated prevalence of RE in Chinese children. Data of identified eligible studies was extracted by two investigators independently. Pooled prevalence of RE and its 95% confidence interval (95% CI) and the time trends of RE were investigated using Meta-analysis methods.

Results

Of the 41 studies covering 1 051 784 subjects, the pooled prevalence of myopia, high myopia, hyperopia and astigmatism in Chinese children was 38.0% (95% confidence interval (CI) = 35.1%-41.1%), 2.8% (95% CI = 2.3%-3.4%), 5.2% (95% CI = 3.1%-8.6%) and 16.5% (95% CI = 12.3%-21.8%), respectively. Subgroup analysis show that children living in urban were at higher risk of RE. Prevalence of myopia and hyperopia were higher in Northern China compared with Southern China and high myopia and astigmatism were higher in Hong Kong, Macau and Taiwan than in mainland China. Regression analysis showed an upward trend in myopia and hyperopia and a downward trend in high myopia and astigmatism with years.

Conclusions

The prevalence of RE is higher in urban areas than in rural for Chinese children. The much higher prevalence of myopia and astigmatism in China compared with foreign countries indicates the important role played by environment and genetic factors. Considering the large magnitude of refractive errors, much more attention should still be paid to RE prevention and treatment strategy development in China.

Trabeculectomy in Staphyloma Eye with High Intraocular Pressure Following Ocular Trauma – A Case Report

BACKGROUND: Ocular trauma may alter the anterior segment condition that may lead to secondary glaucomas such as inflammation, hyphema, angle recession, and lens subluxation. One of the most common procedures to decrease intraocular pressure (IOP) is trabeculectomy by creating pathways that allow aqueous humor to flow out of the anterior chamber. Scleral tissue destruction can cause damage in thin areas (such as posterior to the rectus muscle insertions) as in case of scleritis. CASE REPORT: An 11-year-old boy presented to the Ophthalmology Department of Universitas Sumatera Utara Hospital with a bigger white grayish mass and blurry vision. There was a history of the left ocular trauma 6 years ago, followed by redness of the eye, but not treated properly. On the general examination, the patient’s left eyes looked cloudy. On ocular examination, the left eye visual acuity was 1/300 and IOP was 28 mmHg. Segment anterior examination showed staphyloma from 9 to 12 o’clock, conjunctival injection, corneal scar, shallow anterior chamber, and cloudy lens. We could not asses the posterior segment due to cloudy media. We gave anti-glaucoma medication for 1 month, but the IOP did not decrease. We performed a trabeculectomy to control IOP and to prevent staphyloma from getting bigger. CONCLUSION: Trabeculectomy was an effective procedure to control IOP in a staphyloma eye following ocular trauma.

Analysis of corneal astigmatism and aberration in chinese congenital cataract and developmental cataract patients before cataract surgery

BACKGROUND

To investigate the distribution of corneal astigmatism, aberration, and biometric parameters in Chinese congenital cataract (CC) /developmental cataract patients before cataract surgery.

METHODS

We evaluated eyes of CC /developmental cataract patients scheduled for cataract surgery from January 2016 to September 2019. Astigmatism, aberrations, and biometric parameters were measured with the Pentacam Scheimpflug imaging device (Pentacam HR, Oculus). Cataract was diagnosed and classified by slit-lamp examination after full mydriasis.

RESULTS

We evaluated 538 eyes in 356 patients. The mean values of anterior corneal astigmatism (ACA), posterior corneal astigmatism (PCA), and total corneal astigmatism (TCA) were determined as 1.98 ± 1.06 D (range 0.0‒4.8 D), 0.49 ± 0.26 D (range 0.0‒1.9 D), and 2.09 ± 1.19 D (range 0.2‒8.8 D), respectively. ACA and TCA ≥ 1.25 D was present in 379 eyes (70.3%) and 392 eyes (72.8%), respectively. PCA between 0.25 D and 0.75 D was found in 380 eyes (70.6%). There was a statistically significant positive linear correlation between lower-order aberrations root mean square values (LOA RMS) and corneal astigmatism (CA). Furthermore, in terms of distribution of central cornea thickness, anterior chamber depth, ACA, PCA, and TCA in different types of cataracts, ACA was highest in patients with zonular cataracts. Finally, we found anterior corneal measurements may overestimate WTR astigmatism, underestimate ATR astigmatism, and underestimate oblique astigmatism, respectively.

CONCLUSIONS

Most CC /developmental cataract patients had moderate to high astigmatism and ACA accounted for the largest proportion in the zonular group. This can provide a basis for planning of CC/developmental cataract surgery by ophthalmologists in clinical practice.

Frequency of presenting visual acuity and visual impairment in Chinese college students

AIM

To obtain the baseline data on presenting visual acuity (PVA) and evaluate the prevalence and associated factors for visual impairment based on PVA in 9070 Chinese college students.

METHODS

The freshmen at a university in southern China, including 6527 undergraduate students and 2543 graduate students, were investigated for some socio-demographic characteristics and underwent routine medical examination, including measuring PVA, height, and weight. Visual impairment was defined according to the new World Health Organization criteria for blindness and visual impairment.

RESULTS

In 9070 college students, the mean PVA in the better eye was 0.094±0.163 logMAR. The prevalence of visual impairment based on PVA was 2.7%. Only 38.3% college students had normal visual acuity [PVA equal to 0 logMAR (20/20) in both eyes]. There were 69.8% of students wearing spectacles. Logistic regression showed that home region (non-Guangdong provinces, P<0.0001, OR=1.70) was risk factor for visual impairment while BMI (P=0.001, OR=0.92) was protective factor from visual impairment. Ethnicity (Han Chinese, P<0.0001, OR=3.17) was risk factor for wearing spectacles while age (P=0.01, OR=0.90) was protective factor from wearing spectacles.

CONCLUSION

This study provides the baseline data on PVA and the prevalence of visual impairment in Chinese college students. Our analyses reveal that BMI and home region are associated factors for visual impairment based on PVA, while age and ethnicity are associated factors for wearing spectacles.

Prevalence of Amblyopia and Associated Risk Factors in Tibetan Grade One Children

INTRODUCTION

Amblyopia is an important public health problem and standard screening is quite necessary for early diagnosis and treatment especially for the remote areas. As the place of the largest Tibetan population, the Tibetan Plateau has special geographical characteristics such as high altitude, time zone, and ethnic composition, where very little information is available about the prevalence of amblyopia and other ocular diseases. The article aims to determine the prevalence of amblyopia and associated factors in grade 1 Tibetan children, living in Lhasa, Tibet Autonomous Region.

METHODS

A cross-sectional study was conducted. All the participants were scheduled for comprehensive eye examinations including visual acuity testing, ocular deviation and movement evaluation, cycloplegic refraction and examinations of the external eye, anterior segment, media, and fundus. Amblyopia was assessed in the children according to the standard definition.

RESULTS

A total of 1,856 students participated in the examinations (97.58% response rate). 1,852 students completed all the related examinations, and 34 of them were diagnosed as amblyopia with the prevalence of 1.84% (95% confidence interval [CI]: 1.22-2.45%). Unilateral amblyopia was diagnosed in 23 students (1.24%, 95% CI: 0.74-1.75%), including 16 anisometropic, 4 strabismic, 1 visual deprivational, and 2 mixed. Other 11 students were diagnosed as bilateral amblyopia (0.59%, 95% CI: 0.24-0.94%), including 9 ametropic, 1 deprivational, and 1 with nystagmus. The mean cylinder refraction and absolute value of the spherical equivalent refraction of amblyopic eyes was respectively -2.15 ± 1.52 D and 2.70 ± 2.33 D. Amblyopia was significantly associated with hyperopia (≥+2.00 D, odds ratio [OR] 8.22, 95% CI 3.42-19.72), astigmatism (≤-2.00 D, OR 6.76, 95% CI 2.56-17.85), and anisometropia (≥+0.50 to <+1.00 D, OR 3.95, 95% CI 1.44-10.79; ≥+1.00 D, OR 21.90, 95% CI 8.24-58.18).

CONCLUSIONS

The prevalence of amblyopia in grade 1 students of Lhasa is relatively higher than that of many other ethnic populations in China previously reported. Refractive errors including anisometropia, hyperopia, and astigmatism are the major risk factors of amblyopia.

Prevalence and associated risk factors for childhood strabismus in Lhasa, Tibet, China: a cross-sectional, school-based study

Background

To estimate the prevalence of strabismus and associated risk factors among grade one school children in Lhasa, Tibet, China.

Methods

The Lhasa Childhood Eye Study (LCES) was a cross-sectional, school-based childhood study conducted in Grade one students from primary schools in Lhasa, Tibet, China. Comprehensive ophthalmic examinations and basic systemic examinations were evaluated. A questionnaire survey containing information about children, as well as parents’ information, was sent to the corresponding parents of eligible children. The prevalence of strabismus and its 95% confidence interval was estimated. Univariate and multivariate logistic regression analyses were conducted to determine the associated risk factors.

Results

A total of 1942 eligible grade one students were enrolled, of which 1856 participants completed all examinations. The average age was 6.83 ± 0.46 years, 53% of participants were boys and 1762 were the Tibetan Minority. Over all, the prevalence of strabismus was 68/1856 (3.7%) (95%CI: 2.81,4.52), with no difference between the ages, genders, ethnicities and body mass index, while tilting one’s head when writing may be a risk factor for strabismus (P = 0.004). Strabismus students had mean best corrected visual acuity of 0.16 ± 0.28(LogMAR), over 50% patients with esotropia were hyperopic, and participants who had stereopsis impairments showed a significant difference between esotropia and exotropia (P = 0.026).

Conclusions

The prevalence of strabismus in LCES was 3.7%, which is higher than previous reports from Chinese childhood epidemiology studies. Strabismus is a common contributing factor to amblyopia. Tilting one’s head when writing may be a risk factor. Esotropia is more likely to affect stereopsis and be associated with the refractive state of hyperopia.

Trial registration

The study has finished the clinical registration on Chinese Clinical Trial Registry. (http://www.chictr.org.cn, ChiCTR1900026693).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-020-01732-2.

Visual impairment in rural and migrant Chinese school-going children: prevalence, severity, correction and associations

PURPOSE

To describe changes in the prevalence of visual impairment and glasses ownership with age and as associated with income and population density for visual impairment among rural and urban migrant Chinese students.

DESIGN

Meta-analysis of 12 cross-sectional, school-based studies conducted between 2012 and 2017.

SETTING

Rural and urban migrant schools in seven Chinese provinces.

PARTICIPANTS

A total of 83 273 rural and urban migrant Chinese students aged 6-17 years.

RESULTS

Prevalence of visual impairment (uncorrected visual acuity ≤6/12 in either eye) rose from 19.0% at age 6 to 66.9% at 17, with the overall age-adjusted prevalence higher for girls (35.8%) than for boys (30.1%, p<0.001). The rate of glasses ownership among students who needed them increased from 13.0% at age 6 to 63.9% (p<0.001) at 17 and was significantly higher for girls (37.0%) than boys (34.7%, p<0.001). The unmet need for glasses as a proportion of the student population peaked in junior high school (31.8%). A 1% increase in per capita gross domestic product was associated with a 4.45% rise in uncorrected visual acuity (R²=0.057, p=0.020). Population density was significantly associated with glasses ownership among children (R²=0.359, p=0.012). A 1% population density increase was associated with an increase in the glasses ownership rate of 6.83%.

CONCLUSION

Efforts are needed to improve vision screening coverage in China's schools, particularly junior high schools, as this is when many rural children leave school and glasses coverage is lowest.

Visual impairment and refractive error amongst school-going children aged 6–18 years in Sekhukhune District (Limpopo, South Africa)

Background: Refractive error (RE) and visual impairment (VI) remain major problems affecting school-going children worldwide.Aim: To determine the prevalence and distribution of VI and RE in school-going children aged 6–18 years.Setting: The study was conducted in Sekhukhune District, Limpopo, South Africa.Methods: A multistage random sampling method was used to select school-going children aged 6–18 years from Grades 1 to 12. A total of 326 learners went through eye examinations, which included visual acuity (VA) measurement using a logarithm of the minimum angle of resolution chart, autorefraction under cycloplegia and ocular health assessment.Results: The prevalence of uncorrected, presenting and best-corrected VA of 0.30 M or worse in the better eye was 12.3% (95% confidence interval [CI], 8.70–15.80), 12.3% (95% CI, 8.70–15.80) and 2.1% (95% CI, 0.60–3.70), respectively. Refractive error accounted for 80% (95% CI, 67.6–92.4) of all causes of VI. Myopia was the most prevalent RE (50.7%; 95% CI, 38.8–62.7), followed by astigmatism (36%; 95% CI, 24.3–47.3) and hypermetropia (13.6%; 95% CI, 5.30–21.6). There was no significant difference in the prevalence of RE and VI between males (50.7%; 95% CI, 38.8–62.7) and females (49.3%; 95% CI, 37.3–61.2). Refractive error and VI were higher amongst children aged 14–18 years: 56.7% (95% CI, 44.9–68.6) and 60% (95% CI, 44.8–75.20), respectively.Conclusion: The prevalence of RE and VI amongst school-going children in Sekhukhune District was high, highlighting the need for school visual screening and strategies to address these conditions in that area.

The Association between Childhood Myopia Prevalence and Environmental Factors in China: A Metaregression Analysis

Background. Myopia prevalence varies across the country among schoolchildren in China. Recently, environmental factors have been shown to be important in myopia development and progression. Given China’s geographical diversity with variable environmental factors, we investigated whether environmental factors could explain the regional variations in myopia in mainland China. Methods. We searched PubMed, Web of Science, and Chinese Science Periodical Databases for studies with reports of myopia prevalence in schoolchildren in mainland China from the years 1979 to 2019. Data on environmental factors (annual sunshine hours, temperature, and population density) were obtained from past records. A random-effect univariate metaregression analysis was used to investigate the association between the environmental factors and myopia prevalence and to determine the proportion of variation in regional myopia prevalence that can be attributed to each factor. Results. Forty-nine eligible studies were identified that included 666,864 schoolchildren aged 6 to 20 years. The pooled estimate of myopia prevalence was 32.88% (95% confidence interval: 26.69–39.08%). Univariate metaregression analysis indicated that annual sunshine hours (27.97% of variance), annual temperature (24.66%), and population density (7.06%) significantly contributed to regional myopia prevalence variation (each $p<0.05$ ), while seasonal variation in sunshine hours (1.54%, $p=0.604$ ) was not a significant predictor of myopia prevalence. However, only annual sunshine hours was significantly associated with myopia prevalence in the multivariate metaregression model. Conclusion. Myopia prevalence in children was higher in regions with low sunshine hours, and annual sunshine hours was significantly associated with regional variation in myopia prevalence in mainland China.

Visual Impairment among Primary School Children in Gondar Town, Northwest Ethiopia

Background

An impairment of the visual system at or shortly after birth adversely affects educational performance of children which typically occurs through vision. Limited evidence on the magnitude and causes of visual impairment is one of the reasons for the low priority given to eye care in low-income countries.

Objectives

To estimate the prevalence and determine the causes of visual impairment in primary school children in Gondar town, Northwest Ethiopia.

Materials and Methods

A descriptive cross-sectional study was conducted among 1289 children aged 5–15 years who were randomly selected in 9 primary schools (government and private) from May to June 2016. Visual acuity was measured at 6 m using Snellen's chart, and children with an acuity of less than 6/18 in the better eye underwent refraction and a detailed eye examination. A cause of their impairment was determined. Data were recorded using pretested tools. . Statistical Package for Social Sciences version 16 was used to enter and analyze the data using 95% confidence intervals.

Results

The prevalence of visual impairment was 1.8%. Refractive errors (nearly 70%) followed by strabismus and cataract, each contributing 4.3%, were the most frequent causes of visual impairment in the study population. Majority (87%) of the children had moderate degree of vision impairment, and 10–15-year age groups are the more affected ones. Children of age fifteen and above showed statistically significant association with visual impairment (p=0.005).

Conclusion

The magnitude of visual impairment in primary school children in the study area is significant. School screening programme is recommended to minimize the burden of visual impairment in the study area.

Cerebral Modifications and Visual Pathway Reorganization in Maculopathy: A Systematic Review

Background

Macular degeneration (MD) is one of the most frequent causes of visual deficit, resulting in alterations affecting not only the retina but also the entire visual pathway up to the brain areas. This would seem related not just to signal deprivation but also to a compensatory neuronal reorganization, having significant implications in terms of potential rehabilitation of the patient and therapeutic perspectives.

Objective

This paper aimed to outline, by analyzing the existing literature, the current understanding of brain structural and functional changes detected with neuroimaging techniques in subjects affected by juvenile and age-related maculopathy.

Methods

Articles using various typologies of central nervous system (CNS) imaging in at least six patients affected by juvenile or age-related maculopathy were considered. A total of 142 were initially screened. Non-pertinent articles and duplicates were rejected. Finally, 19 articles, including 649 patients, were identified.

Results

In these sources, both structural and functional modifications were found in MD subjects' CNS. Changes in visual cortex gray matter volume were observed in both age-related MD (AMD) and juvenile MD (JMD); in particular, an involvement of not only its posterior part but also the anterior one suggests further causes besides an input-deprivation mechanism only. White matter degeneration was also found, more severe in JMD than in AMD. Moreover, functional analysis revealed differences in cortical activation patterns between MD and controls, suggesting neuronal circuit reorganization. Interestingly, attention and oculomotor training allowed better visual performances and correlated to a stronger cortical activation, even of the area normally receiving inputs from lesioned macula.

Conclusion

In MD, structural and functional changes in cerebral circuits and visual pathway can happen, involving both cerebral volume and activation patterns. These modifications, possibly due to neuronal plasticity (already observed and described for several brain areas), can allow patients to compensate for macular damage and gives therapeutic perspectives which could be achievable through an association between oculomotor training and biochemical stimulation of neuronal plasticity.

Genome-wide DNA methylation profiles may reveal new possible epigenetic pathogenesis of sporadic congenital cataract

Aim: To investigate the possible epigenetic pathogenesis of sporadic congenital cataract. Materials & methods: We conducted whole genome bisulfite sequencing on peripheral blood from sporadic binocular or monocular congenital cataract patients and cataract-free participants. Results: We found massive differentially methylated regions within the whole genomes between any two groups. Meanwhile, we identified five genes (ACTN4, ACTG1, TUBA1A, TUBA1C, TUBB4B) for the binocular and control groups and TUBA1A for the monocular and control groups as the core differentially methylated region-related genes. The proteins encoded by these core genes are involved in building cytoskeleton and intercellular junctions. Conclusion: Changes in the methylation levels of core genes may disturb the function of cytoskeleton and intercellular junctions, eventually leading to sporadic congenital cataract.

Academic Implications of Uncorrected Refractive Error: A Study of Sokoto Metropolitan Schoolchildren

Background:

The Sustainable Development Goal 4 ensures that all children have an inclusive and equitable quality education. However, uncorrected refractive errors (UREs) have been a major cause of limitations with regard to quality education as vision plays a vital role in child learning and development. Thus, any problem affecting the child's vision could adversely affect the quality of the child's education.

Aims:

The aim of this research was to assess the quality of education of the children with URE in Sokoto metropolis, Sokoto State, Nigeria.

Methods:

A cross-sectional survey of schoolchildren in four randomly selected primary schools within Sokoto metropolis was carried out from July 2016 to October 2016 using the illiterate “E” chart and a pinhole. Relevant history and basic ocular examinations were done using a multistage sampling technique.

Statistical Analysis:

Data were analyzed using the Statistical Package for Social Sciences (IBM SPSS) version 20.

Results:

A total of 113 students were surveyed; 56 (49.6%) males and 57 (50.4%) females. The age range was between 5 and 15 years, and the mean age was 10.89 ± 2.27 years. The prevalence of URE was 9.7%, with more than half of the students within the age group of 10–12 years (P = 0.018) and more common in females (54.5%) than males (45.5%) (P = 0.775). More than 90% of the respondents had never had a prior eye examination. The average mean academic performance of the pupils with URE (49.54% ±10.49%) was statistically significantly lower than those without refractive error (71.08 ± 10.09), mean difference = 21.55 (95% confidence interval, 15.18–27.92) (t = 6.70, P = 0.000).

Conclusions:

The negative implications of URE on the quality of education and other socioeconomic aspects of life underscore the need to increase efforts on its screening and increase other relevant interventional measures.

Visual impairment and associated factors among primary school children in Gurage Zone, Southern Ethiopia

Background

Visual impairment is one of the major public health problems worldwide, especially in developing countries.

Objective

To determine the prevalence of visual impairment and its associated factors among school children in Gurage Zone, Southern Ethiopia

Methods

A cross sectional study was conducted in eight primary schools of Gurage Zone. A total of 1064 pupils, of whom589 boys and 475 girls were selected using multistage sampling technique. Socio-demographic characteristics of the participants were collected using structured questionnaires and visual acuity was measured using Snellen's chart. Logistic regression analysis was used to determine the associated factors of visual impairment.

Results

The prevalence of visual impairment was 5.2%. Factors significantly associated with visual impairment were age group of 13–18 years (AOR = 9.44, 95% CI = 3.83 – 23.25), school grade level of 5- 8 (AOR = 2.97, 95% CI = 1.23 – 7.17), rural residents (AOR = 2.59, 95% CI = 1.22 – 5.54), family's monthly income of less than 2000 Ethiopian Birr (AOR = 2.87, 95% CI = 1.08 – 7.61) and visually impaired parents (AOR = 2.16, 95% CI = 1.06 – 4.39).

Conclusion

This study found that the prevalence of visual impairment was 5.2%.

Prevalence of the thoracic scoliosis in children and adolescents candidates for strabismus surgery: results from a 1935-patient cross-sectional study in China

PURPOSE

No study so far has paid attention to strabismus-related spinal imbalance. This study aimed to determine the epidemiology of thoracic scoliosis in children and adolescents with strabismus and investigate the association of two diseases.

METHODS AND DESIGN

A cross-sectional study. Study group consists of 1935 consecutive candidates for strabismus surgery (4-18 years); Control group consists of the age- and sex-matched patients with respiratory diseases. All subjects underwent a screening program based on chest plain radiographs using the Cobb method. Their demographic information, clinical variables and results of Cobb angle were recorded and analyzed.

RESULTS

A significantly higher prevalence of thoracic scoliosis (289/1935, 14.94% versus 58/1935, 3.00%) was found in study group compared with control group. Among strabismic patients, the coronal thoracic scoliosis curve mainly distributed in right and in main thoracic (198/289) and in the curves 10°-19° (224/289); Age range 7-9 years (103/1935), female (179/1935) and concomitant exotropia patients (159/851) were more likely to have thoracic scoliosis. According to the logistic regression, thoracic scoliosis had no significant association with age, BMI, duration of illness and onset age (p > 0.05). However, gender, BCVA, type of strabismus and degree of strabismus showed a significant relationship with the prevalence of thoracic scoliosis (p < 0.05).

CONCLUSIONS

With a pooled prevalence of 14.94%, strabismus patients showed a great higher risk of developing thoracic scoliosis. Screening for scoliosis in strabismus patients can be helpful to discover a high prevalence of potential coronal scoliosis. More attention should be paid to ophthalmological problems in patients with scoliosis. These slides can be retrieved under Electronic Supplementary Material.

A Serial Cross-Sectional Analysis of the Prevalence, Risk Factors and Geographic Variations of Reduced Visual Acuity in Primary and Secondary Students from 2000 to 2017 in Hong Kong

Background: We would like to investigate the prevalence trend, potential risk factors and geographic features of reduced visual acuity (VA) in primary and secondary schoolchildren of Hong Kong. Methods: This was a serial cross-sectional study using historical data of schoolchildren aged 6 to 15 years from the annual health checks conducted at Student Health Service Centers across Hong Kong, for the school years of 2000/2001 to 2016/2017. Results: The prevalence of reduced VA increased from 49.23% (95% CI, 48.99-49.47) in 2000/2001 to 54.34% (95% CI, 54.10-54.58) in 2011/2012 but decreased to 51.42% (95% CI, 51.17-51.66) in 2016/2017. Girls were less susceptible than boys at age 6-7 (and in grade primary 1-2), but more susceptible at older ages. The prevalence in junior grades increased while the risk effect of grade reduced over the past 17 years. Geographic variation on the risk for reduced VA existed and spatial autocorrelation was positive. The difference in prevalence of reduced VA between Hong Kong and mainland China has decreased in recent years. Cross-border students living in mainland China were associated with a lower risk for reduced VA. Conclusions: Further study was proposed to investigate the environmental association between students living in and outside Hong Kong with the prevalence of reduced VA. Multi-level research should also be conducted to investigate the influence of compositional and contextual factors on the prevalence of reduced VA.

Characterization of Intelligence in Children with Exotropia

The effect of exotropia on the intelligence of children is unknown. This study aimed to assess the intelligence in children with exotropia and investigate the influence of the main clinical indexes of strabismus on intelligence. Eighty-four participants aged 8–12 years were enrolled, including 37 patients with exotropia (exotropia group) and 47 normal individuals (normal group). Intelligence was assessed by the Wechsler Intelligence Scale for Children—Fourth Edition (WISC-IV), including the Verbal Comprehension Index (VCI), Perceptual Reasoning Index (PRI), Working Memory Index (WMI), Processing Speed Index (PSI), and Full-Scale Intelligence Quotient (FSIQ). The exotropia group had a significantly lower PRI score but a higher PSI score than the normal group. However, there was no significant difference in the WMI, VCI, and FSIQ between groups. Multiple linear regression showed that PRI–WMI and PRI–PSI differences were significantly lower in the exotropia group. Inter-subscale correlations analysis showed that the pattern of intelligence structure was different between groups. The type of exotropia, angle of deviation, duration of symptoms, and stereoacuity had no effect on the intelligence of children with exotropia. Children with exotropia had a relatively worse performance in the perceptual reasoning skill but a better processing speed and a different pattern of intelligence structure.

Prevalence of amblyopia among preschool children in central south China

AIM

To determine the prevalence and factors associated with amblyopia among children aged 30-83mo in central south of China.

METHODS

A population-based, cross-sectional study was conducted in children aged 30-83mo in Changsha (an urban city) and Zhangjiajie (a rural area) in central south of China. Clinical examinations including ocular alignment, ocular motility, visual acuity (VA), prism cover test, cycloplegic refraction, slit lamp examination and fundus examination were performed by trained study ophthalmologists and optometrists. Unilateral amblyopia was defined as a 2-line difference between eyes with VA<20/32 in the worse eye and with coexisting anisometropia [≥1.00 D spherical eutivalent (SE) for hyperopia, ≥3.00 D SE for myopia, and ≥1.50 D for astigmatism], strabismus, or past or present visual axis obstruction. Bilateral amblyopia was defined as VA in both eyes <20/40 (≥ 48-month-old) and <20/50 (< 48-month-old), with coexisting hyperopia ≥4.00 D SE, myopia ≤-6.00 D SE, and astigmatism ≥2.50 D, or past or present visual axis obstruction.

RESULTS

There were 8042 children enrolled and 7713 children were screened. The amblyopia prevalence in children aged 30-83mo was 1.09% (95% confidence interval, 0.86%-1.35%) with no age (P=0.81), gender (P=0.46) or area distribution (P=0.93) differences. Of these, 0.68% were unilateral cases and 0.41% were bilateral cases. Underlying causes included anisometropia (40%), binocular refractive error (36%), strabismus (14%) and deprivation (10%). Hyperopia combined with astigmatism was the frequent refractive error for ametropic and anisometropic amblyopia.

CONCLUSION

In this rural and urban Chinese population, 1.09% of children with 30-83mo of age had amblyopia, a prevalence rate similar to that of many other studies. Anisometropia and refractive error are the most common causes of unilateral and bilateral amblyopia respectively.

Socio-economic status, visual impairment and the mediating role of lifestyles in developed rural areas of China

PURPOSE

To examine the impacts of socio-economic status (SES) on visual impairment (VI), and the mediating role of lifestyles in developed rural areas of China.

METHODS

A cross-sectional study was conducted among people living in rural districts of Tianjin, a developed municipality in China. An interviewer-administered survey along with free eye screenings was conducted with participants. The questionnaire included questions about demographic characteristics, SES, medical histories and lifestyles. Presenting visual acuity (PVA) and main causes of VI were identified by ophthalmologists. χ2 test was undertaken to determine whether significant differences (p<0.05) exist between VI and demographic, SES, medical history and lifestyle factors. A stepwise regression method was conducted to investigate whether lifestyles play mediating roles between SES and VI. Multivariable logistic and ordinal logistic regression were used contingent on different types of dependent variables in each regression, and adjusted odds ratio (OR) values were estimated.

RESULTS

Of the 12,233 participants, 6,233 were male (50.59%); the mean age was 34.61 years; 310 (2.54%) had VI. Hypertension, diabetes and cardiopathy were main medical histories, with 1,640 had hypertension (13.41%), 854 had diabetes (6.98%) and 483 had cardiopathy (3.95%). About SES factors, higher education level (Adjusted OR, 0.84; 95% CI, 0.75-0.95) and higher income level (Adjusted OR, 0.54; 95% CI, 0.39-0.76), were significantly associated with VI in a gradient across severity of VI. Lifestyles including smoking (Adjusted OR, 1.55; 95% CI, 1.31-1.83) and drinking (Adjusted OR, 1.36; 95% CI, 1.06-1.74) played mediating roles between SES and VI when considering the full sample. Besides smoking and drinking, reading every week (Adjusted OR, 2.07; 95% CI, 1.53-2.82) and exercising more than 2h every day (Adjusted OR, 0.39; 95% CI, 0.15-1.00) also played mediating roles between SES and VI when considering the subsample (age≥16).

CONCLUSION

This study revealed the crucial impacts of SES factors on VI, and the mediating role played by several lifestyles. Targeted public health interventions for reducing VI should thus be proposed in developed rural areas of China.

Long-Term Natural Course of Pathologic Myopia in Chinese Patients

Purpose

To investigate the natural progression in Chinese patients with pathological myopia (PM) and its associated factors.

Methods

The medical records of 28 patients with PM (worse than −6 diopter), including 31 eyes of 21 children and 12 eyes of 7 adults, were studied. All of the patients underwent a complete ophthalmologic examination at least twice over 3-year period, including the measurement of refractive error (shown as spherical equivalent, SE), axial length (AL), intraocular pressure, visual acuity (uncorrected visual acuity, UCVA, and best-corrected visual acuity, BCVA), and dilated fundus examination.

Results

The median AL of adults increased significantly from 29.8 mm to 31.43 mm over 5.4 years follow-up (P=0.0037), accompanied with the median SE progressing significantly from −16.4 D to −18.94 D (P=0.0005). Similarly, the median AL of children increased significantly from 26.13 mm to 27.81 mm over 3.9 years (P=0.0001). However, the improvements of UCVA and BCVA in children were significant (P=0.0304, 0.0001), and they had a negative correlation with age (P=0.0010, 0.0005). Also, UCVA and BCVA in children with bilateral PM were significantly better than those with unilateral PM (P=0.0385, 0.0210).

Conclusions

Fundus degenerations in children with pathological myopia may lead its way since the age of 10 years. Besides, children with bilateral pathological myopia can have parallel development in visual acuity.

The sonic hedgehog signaling pathway is suppressed following PCB1254 exposure during retinal development

Polychlorinated biphenyl (PCB) has been reported to have detrimental effects on retinal development. In order to explore the role of Shh signaling in retinal development after PCB₁₂₅₄ exposure in vivo and in vitro, zebrafish and RGC-5 retinal cell line were used. Compared with the controls, PCB exposure inhibited proliferation and increased the apoptosis levels. The expression of Shh mRNA decreased in the PCB₁₂₅₄ -treated groups both in vivo and in vitro compared with that of the controls. The ptch2 mRNA expression increased in the experimental groups. The expression of gli2 mRNA decreased in the PCB₁₂₅₄ -treated groups. Immunofluorescence and western blotting assays confirmed that the expression of Shh proteins decreased in PCB₁₂₅₄ -treated groups compared with control groups. Moreover, ptch2 protein levels increased in the PCB₁₂₅₄ -treated groups as well as the decreased protein expressions of gli1 and gli2. These results demonstrated that Shh signaling pathway may participate in the damage of retinal development caused by PCB₁₂₅₄ exposure, providing evidence that eye diseases could be caused by environmental pollutants.

Prevalence of amblyopia and strabismus in Hani school children in rural southwest China: a cross-sectional study

PURPOSE

To determine the prevalence rate of amblyopia and strabismus in Chinese Hani ethnic school-aged children.

METHODS

All grade 1 and grade 7 students in Mojiang Hani Autonomous County, located in southwest China, were invited for comprehensive eye examinations performed by experienced ophthalmologists and optometrists, including visual acuity, ocular alignment and movements, cycloplegic autorefraction, anterior segment and fundus examinations. Standard definitions of amblyopia and strabismus were applied to calculate their prevalence rate.

RESULTS

A total of 1656 (91.0% response rate) grade 1 Hani students and 1394 (92.8% response rate) grade 7 Hani students participated in the study. Amblyopia was present in 25 Hani students (0.82%, 95% CI 0.55% to 1.20%), with no significant differences in grade (p=0.42) and gender (p=0.69). Among these 25 amblyopic children, 17 had unilateral amblyopia and eight had bilateral amblyopia, including 16 anisometropic, eight binocular refractive and one strabismic. Strabismus was found in 59 Hani students (1.93%, 95% CI 1.50% to 2.48%), including 47 with intermittent exotropia, six with constant exotropia, five with constant esotropia and one with unilateral superior oblique palsy. The prevalence rate of strabismus was higher in grade 7 students than grade 1 students with borderline significance (2.44%vs1.50%, p=0.07), but was similar by gender (2.16% in boys vs 1.68% in girls, p=0.36).

CONCLUSION

The prevalence of amblyopia and strabismus in Chinese Hani school children are both lower than that previously reported for Chinese Han children in China and for many other racial/ethnic populations from non-China studies. Refractive error is the major cause for amblyopia and intermittent exotropia is the primary strabismus type.

Effect of school eye health promotion on children's eye health literacy in Vietnam

Health promotion intervention in schools is a useful strategy to improve students' health awareness. The purpose of this study was to assess the effect of eye health promotion interventions on eye health literacy in school children in Vietnam. A piloted questionnaire was administered to 300 children from five secondary schools in Ba Ria-Vung Tau, Vietnam at baseline and re-administered after the eye health promotion interventions. McNemar chi-square and logistic regression were used for statistical analysis. A total of 300 children aged 12-15 years (mean, 13.3 ± 1.3 years; 60% female) participated in the baseline survey. The participation rate in the post-health promotion survey was 94.7%. After the health promotion interventions, number of children who had correct eye health knowledge increased by 10-20% (60-75% to 70-95%), more children reported having had an eye examination (63.3% to 84.7%; p < 0.001) and more reported wearing spectacles (36.1% to 43.4%; p = 0.04). Children in urban schools were twice as likely to have improved knowledge of vision loss compared with children in rural schools (odds ratio, 2.1-4.1; p = 0.01 to p < 0.001). Children from rural schools had significantly higher odds of visiting doctor after the eye problems worsened (odds ratio, 4.5; p < 0.001). These results imply that eye health promotion interventions significantly improve eye health knowledge, attitudes and practices of school children. Additionally, participation of parents and teachers as change agents may further improve children's health literacy.

Updates on managements of pediatric cataract

Purpose

A comprehensive review in congenital cataract management can guide general ophthalmologists in managing such a difficult situation which remains a significant cause of preventable childhood blindness. This review will focus on surgical management, postoperative complications, and intraocular lens (IOL)-related controversies.

Methods

Electrical records of PubMed, Medline, Google Scholar, and Web of Science from January 1980 to August 2017 were explored using a combination of keywords: "Congenital", "Pediatric", "Childhood", "Cataract", "Lens opacity", "Management", "Surgery", "Complication", "Visual rehabilitation”, and "Lensectomy". A total number of 109 articles were selected for the review process.

Results

This review article suggests that lens opacity obscuring the red reflex in preverbal children and visual acuity of less than 20/40 is an absolute indication for lens aspiration. For significant lens opacity that leads to a considerable risk of amblyopia, cataract surgery is recommended at 6 weeks of age for unilateral cataract and between 6 and 8 weeks of age for bilateral cases. The recommended approach in operation is lens aspiration via vitrector and posterior capsulotomy and anterior vitrectomy in children younger than six years, and IOL implantation could be considered in patients older than one year. Most articles suggested hydrophobic foldable acrylic posterior chamber intraocular lens (PCIOL) for pediatrics because of lower postoperative inflammation. Regarding the continuous ocular growth and biometric changes in pediatric patients, under correction of IOL power based on the child's age is an acceptable approach. Considering the effects of early and late postoperative complications on the visual outcome, timely detection, and management are of a pivotal importance. In the end, the main parts of post-operation visual rehabilitation are a refractive correction, treatment of concomitant amblyopia, and bifocal correction for children in school age.

Conclusions

The management of congenital cataracts stands to challenge for most surgeons because of visual development and ocular growth. Children undergoing cataract surgery must be followed lifelong for proper management of early and late postoperative complications. IOL implantation for infants less than 1 year is not recommended, and IOL insertion for children older than 2 years with sufficient capsular support is advised.

Prevalence and Determinants Associated With Spectacle-Wear Compliance in Aphakic Infants

PURPOSE

We assess the prevalence of spectacle wear and the factors associated with compliance among aphakic infants with congenital cataracts who underwent lens extraction in South China.

METHODS

Infants aged 3 months to 3 years were enrolled from among participants in the Childhood Cataract Program of the Chinese Ministry of Health (CCPMOH). The prevalence and potential determinants of spectacle-wearing compliance were identified from interviews with the infants' caregivers.

RESULTS

Among 192 infant caregivers, the mean (SD) age of the infants was 1.89 (0.50) years, and 57% were males. Compliance was 30.9% in the 3-month- to 1-year-old age group, 78.0% in the 1- to 2-year-old age group, and 87.0% in the 2- to 3-year-old age group. The following two factors were associated with spectacle-wearing compliance: softness of the spectacles frame (β = 1.273, P = 0.002, odds ratio [OR] = 3.6, 95% confidence interval [CI] = 1.6-8.0) and communication with other caregivers regarding the spectacle-wearing experience (β = -2.955, P = 0.034, OR = 0.1, 95% CI = 0-0.8).

CONCLUSIONS

Compliance with spectacle wear was low during the earlier stage, but increased with time in aphakic infants. However, overall compliance should be improved. Therefore, efficient strategies aimed at improving spectacle-wearing compliance are needed.

TRANSLATIONAL RELEVANCE

These findings reveal the low spectacle-wearing compliance in aphakic infants and support useful information to improve compliance.

Prevalence of amblyopia in Bulgaria

Introduction: The purpose of this study was to establish the prevalence of amblyopia in children, aged 4 to 10 years, in Bulgaria, who underwent a complete eye examination.Methods: The study was designed as cross-sectional epidemiological study, and the results were calculated in percentages. A complete ophthalmological examination was performed on 1,675 children, aged 4 to 10 years (mean age 7.7 years), during the period 01 Feb 2017-21 April 2017, in five cities, in the western part of Bulgaria. All children were verbal, none of them had a neurologic deficit or mental development delay and a complete examination was successfully performed. The ophthalmological examination consisted of: autorefractometry (using pediatric autorefractor with infrared photoretinoscopy), visual acuity, best-corrected visual acuity (BCVA) and visual acuity with pinhole occluder, cover/uncover and alternate cover test, Worth four-dot test, stereopsis, biomicroscopy and funds examination. Amblyopia was defined as reduction of the BCVA for near and far distances under 40/60 on one or on both eyes in the absence of any pathology of the eye, excluding a pathology leading to stimulus deprivation amblyopia, and in the presence of an amblyogenic factor.Results: Out of 1,675 children, 42 (2.5%) were diagnosed with amblyopia: 7% had strabismic amblyopia (3), 59% had anisometropic amblyopia (25), 31% had isoametropic amblyopia (13), and 3% deprivation amblyopia (1). Unilateral amblyopia was diagnosed in 73% (27) of the cases and bilateral amblyopia in 27% (15). For 45% (754) of the children, it was their first visit to an ophthalmologist.Conclusions: The prevalence of amblyopia among these patients (2.5%) is correlating well with the expected, based on data from other authors, between 1.5% and 3.5%. The fact that nearly half of the children (45%) have not been examined by an ophthalmologist is, however, alarming. The lack of a national screening program in Bulgaria could be the main reason. Other factors include: insufficient number of pediatric ophthalmologists in the country and the lack of awareness among the parents.

Global and regional estimates of prevalence of amblyopia: A systematic review and meta-analysis

Background: Amblyopia is one of the most important causes of vision impairment in the world, especially in children. Although its prevalence varies in different parts of the world, no study has evaluated its prevalence in different geographical regions comprehensively. The aim of the present study was to provide global and regional estimates of the prevalence of amblyopia in different age groups via a systematic search.Methods: In this study, international databases, including Embase, Scopus, PubMed, Web of Science, and other relevant databases, were searched systematically to find articles on the prevalence of amblyopia in different age groups published in English. The prevalence and 95% CI were calculated using binomial distribution. The Cochran's Q-test and I² statistic were applied to assess heterogeneity, a random-effects model was used to estimate the pooled prevalence, and a meta-regression method was utilized to investigate the factors affecting heterogeneity between studies.Results: Of 1252 studies, 73 studies were included in the analysis (sample volume: 530,252). Most of these studies (n = 25) were conducted in the WHO-Western Pacific Regional Office. The pooled prevalence estimate of amblyopia was 1.75% (95% CI: 1.62-1.88), with the highest estimate in European Regional Office (3.67%, 95% CI: 2.89-4.45) and the lowest in African Regional Office (0.51%, 95% CI: 0.24-0.78). The most common cause of amblyopia was anisometropia (61.64%). The I² heterogeneity was 98% (p < 0.001). According to the results of univariate meta-regression, the variables of WHO region (b: 0.566, p < 0.001), sample size (b: -0.284 × 10^-4, p: 0.025), and criteria for definition of amblyopia (b: -0.292, p: 0.010) had a significant effect on heterogeneity between studies, while age group, publication date, and cause of amblyopia had no significant effect on heterogeneity.Conclusion: The prevalence of amblyopia varies in different parts of the world, with the highest prevalence in European countries. Geographical location and criteria for definition of amblyopia are among factors contributing to the difference across the world. The results of this study can help stakeholders to design health programs, especially health interventions and amblyopia screening programs.

Prevalence of refractive errors in Tibetan adolescents

Background

The prevalence of adolescent eye disease in remote areas of the Qinghai-Tibet Plateau has rarely been reported. To understand the prevalence of common eye diseases in Tibet, we performed ocular-disease screening on students from primary and secondary schools in Tibet, and compared the prevalence to that in the Central China Plain (referred to here as the “plains area”).

Methods

The refractive status of students was evaluated with a Spot™ vision screener. The test was conducted three or fewer times for both eyes of each student and results with best correction were recorded.

Results

A total of 3246 students from primary and secondary schools in the Tibet Naidong district were screened, yielding a refractive error rate of 28.51%, which was significantly lower than that of the plains group (28.51% vs. 56.92%, p < 0.001). In both groups, the prevalence of refractive errors among females was higher than that among males.

Conclusions

We found that Tibetan adolescents had a lower prevalence of refractive errors than did adolescents in the plains area, which may be related to less intensive schooling and greater exposure to sunlight.

Prevalence of Blindness and Low Vision in Iran: A Systematic Review and Meta-Analysis

PURPOSE

Visual impairment is responsible for medical, mental, and socio-economic problems. Several studies have investigated the prevalence of blindness and low vision in different parts of Iran. This study aims to estimate the pooled results of these studies to estimate the total prevalence of this problem in Iran.

METHODS

National and international databases were searched using specific keywords. The selected primary studies were quality assessed using STROBE checklist. According to the results of the heterogeneity tests (Cochrane and I-squared indices), fixed- or random-effect models were applied to estimate the pooled results. The factors responsible for the heterogeneity were investigated using meta-regression models. The point and pooled estimates were presented by forest plots, and the presence of publication bias was assessed based on Egger test.

RESULTS

Considering the results of 10 eligible studies showed that the prevalence (95% confidence intervals) of blindness among men, women, urban, and rural population as well as total population was 0.96% (0.60-1.31), 1.00% (0.70-1.31), 0.81% (0.19-1.44), 0.89% (0.45-1.32), and 1.02% (0.71-1.34), respectively. Prevalence (95% confidence intervals) of low vision among men, women, urban, and rural populations and also total populations was estimated at 2.19% (1.60-2.79), 2.60% (2.08-3.12), 2.81% (1.26-4.36), 3.67% (2.17-5.17), and 2.85% (2.12-3.58), respectively.

CONCLUSION

Our meta-analyses showed that more than 3% of Iranian people are suffering from visual problems. In addition, we found that prevalence of blindness and low vision among Iranian women was more common than that of Iranian men and also was higher in rural areas than urban areas.