The prevalence of refractive errors in the Middle East: a systematic review and meta-analysis

Long-term ocular complications after kidney transplantation

To assess long-term ocular complications and identify factors affecting these complications in pre-emptive and dialysis patients who have undergone kidney transplantation. We included 548 patients who had a complete ophthalmologic examination at least one year after kidney transplantation. The patients were divided into two groups: those who received dialysis before kidney transplantation (group 1) and those who did not (group 2). We recorded the presence of diabetes mellitus (DM) and hypertension (HT), which could contribute to concomitant retinopathy. Data collected included best corrected visual acuity (BCVA), refractive error (measured with KR-8900; Topcon, Tokyo, Japan), intraocular pressure (IOP, measured with Full Auto Tonometer TX-F; Topcon), slit-lamp examination of the anterior segment, and dilated fundus examination for both eyes. Refractive error, lens opacity, pinguecula, pterygium, arcus lipoides, corneal calcification, macular drusen, central serous chorioretinopathy (CSC), hypertensive retinopathy, and diabetic retinopathy were all recorded. All patients received a maintenance immunosuppressive protocol consisting of combinations of steroids, calcineurin inhibitors (CNI), mycophenolate mofetil, and mammalian target of rapamycin (mTOR) inhibitors. Our study included 257 recipients in group 1 and 291 recipients in group 2. In group 1, 37 recipients (12.7%) required myopic correction, while 35 recipients (13.6%) in group 2 needed similar correction. Additionally, 47 recipients (16.2%) in group 1 required hyperopic correction, compared to 35 recipients (13.6%) in group 2. There was no statistically significant difference between the two groups (p > 0.05).Regarding anterior segment findings, 56 recipients (21.8%) in group 1 and 35 recipients (12%) in group 2 were diagnosed with dry eye, with a statistically significant higher incidence in group 1 (p = 0.003). The rates of arcus lipoides, pinguecula, pterygium, cataract, and glaucoma were similar in both groups (p > 0.05). For posterior segment findings, diabetic retinopathy was observed in 65 patients (25.3%) in group 1 and 47 patients (16.2%) in group 2, showing a statistically significant higher incidence in group 1 (p = 0.011). Other posterior segment conditions, including macular drusen, hypertensive retinopathy, and central serous chorioretinopathy (CSC), were present at similar rates in both groups, with no statistically significant differences found (p > 0.05). We identified dry eyes, cataracts, and retinopathy as the most common ocular complications, with dry eyes and diabetic retinopathy being significantly more prevalent in group 1. Our study indicates that the risk of developing and progressing diabetic retinopathy is higher in patients who received dialysis before transplantation compared to those who underwent pre-emptive transplantation. This finding underscores the importance of preoperative factors in the development of ocular complications after successful kidney transplantation, independent of postoperative factors.

Atopic disease and astigmatism: a population-based study

OBJECTIVES

To assess the relationship between atopic disease and astigmatism in adolescence and young adulthood.

METHODS

In this population-based cross-sectional study 897,811 medical records of Israeli adolescents and young adults without keratoconus were reviewed. The prevalence of low-to-moderate (3.00 > D ≥ 0.75) and high ( ≥ 3.00 D) astigmatism were calculated in cases with and without atopic disease, including ocular atopic disease (OAD), asthma, allergic rhinitis, atopic dermatitis, angioedema/urticaria, and history of anaphylaxis. Relationships were analysed using multinominal logistic regression, with adjustments for relevant sociodemographic factors.

RESULTS

A total of 897,811 adolescents were included in the analysis (mean age 17.2 ± 0.8 years, 57.8% men). OAD was found in 4702 individuals, with a prevalence of 0.5%. Adolescents with OAD demonstrated a gradual increase in odds ratio (OR) for low-to-moderate and for high astigmatism (OR 1.16, 95% CI 1.07-1.27 and OR 2.10, 95% CI 1.63-2.70, respectively). This group also showed increased OR for with-the-rule astigmatism (OR 1.34, 95% CI 1.21-1.48). Other atopic diseases were associated with more modest ORs for low-to-moderate (OR 1.09, 95% CI 1.07-1.11) and for high astigmatism (OR 1.10, 95% CI 1.02-1.19), persisting across all axis orientations. Sensitivity analysis revealed a dose-response relationship between OAD severity and astigmatism, and consistent point estimates in a group of 1331 adolescents diagnosed with OAD during military service.

CONCLUSIONS

This study establishes an association between OAD and astigmatism, highlighting the importance of effective OAD management. Further research into tailored therapeutic interventions that address both conditions concurrently is needed.

Efficacy of single-step transepithelial photorefractive keratectomy in myopia, hyperopia and astigmatism-a systematic review

BACKGROUND

This systematic review assesses the efficacy of single-step transepithelial photorefractive keratectomy (tPRK) in terms of postoperative pain, epithelial healing, postoperative haze and visual acuity. It also compares single tPRK to two-step tPRK where data is available.

METHODS

This systematic review adhered to the PRISMA reporting guidelines (Preferred Reporting Items for Systematic Reviews and Meta-analyses). An electronic literature search was conducted on PUBMED, Scopus, and Google Scholar. The quality of the studies included in this systematic review was evaluated using the Newcastle Ottawa Scale (NOS). The protocol of this systematic review was registered on PROSPERO with ID CRD42024494717.

RESULTS

A total of 11 studies published between 2013 and 2023 were included in this systematic review. Studies revealed a significant improvement in visual acuity with both single-step tPRK and two-step tPRK. Two studies showed that single-step tPRK not only offers a better UDVA but also a significant improvement in the manifest sphere, cylinder, and spherical equivalent at various follow-up periods compared to two-step tPRK. One study demonstrated the broad effectiveness of single-step tPRK for myopia correction across low-, moderate-, and high-severity groups. Rapid epithelial healing was a consistent finding. Complete epithelial healing within 72 h was noted in 100% of eyes treated with single-step tPRK in one of the studies. The incidence of corneal haze following tPRK was generally low across the studies. Post-tPRK pain scores were initially lower in the single-step tPRK group. One study reported that the maximum pain level within the first four days after surgery was significantly lower in the single-step tPRK group than in the two-step tPRK group.

CONCLUSION

Both two-step and single-step tPRK are safe refractive procedures. Single-step tPRK, because of less haze formation, lower pain scores, faster healing, and greater effectiveness in improving visual acuity, is superior to the two-step technique.

TRIAL REGISTRATION

The protocol of this systematic review was registered on PROSPERO with ID CRD42024494717.

The Burden of Blindness and Vision Impairment in the Middle East and North Africa: A Global Burden of Disease 2019 Perspective

PURPOSE

This study analyzes the prevalence, causes, and distribution of blindness and moderate-to-severe vision impairment (MSVI) in the Middle East and North Africa (MENA) using the Global Burden of Disease (GBD) 2019 dataset.

METHODS

The GBD 2019 dataset was used to analyze vision impairment across 21 countries in MENA according to the Snellen chart classification (moderate vision impairment with presenting visual acuity worse than 6/18, severe impairment worse than 6/60, blindness worse than 3/60). Age-standardized prevalence and regional variations were compared to global averages. An exponential linear regression model was used to forecast MSVI and blindness in the year 2050.

RESULTS

As of 2019, approximately 37.2 million people in MENA experienced blindness or vision loss. Although the age-standardized prevalence of vision impairment and blindness in MENA decreased from 1990 to 2019 due to improvements in healthcare, the absolute number has almost doubled (18.58 million in 1990 to 37.19 million in 2019) due to population growth and aging. Between 1990 to 2019, the population aged 70 and older in MENA grew from 7.2 million to over 19.2 million. Lastly, our predictions indicate an 86% increase in the number of individuals with vision loss by 2050.

CONCLUSION

The largest causes of moderate vision loss were refractive errors and cataracts, respectively, while the major causes of blindness were cataracts and glaucoma, respectively. The projection of increased vision impairment by 2050 underscores the urgent need for policy changes and efficient resource distribution to improve healthcare access and interventions.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Refractive error and vision related quality of life

BACKGROUND

To investigate and compare the vision-related quality of life (QOL) in different types of refractive error (RE).

METHODS

This cross-sectional study was performed on 200 subjects, categorized into four groups of 50 each, consisting of subjects with myopia, hyperopia, astigmatism, and emmetropia, the latter being the control group. The mean age of the participants was 23.88 ± 5.87 (range, 15 to 38: 110 females and 90 males). RE was defined as myopia, spherical equivalent (SE) < -0.25 diopters (D), hyperopia, SE > + 0.25 D, astigmatism, cylinder < -0.25 D, and emmetropia (-0.25 ≤ SE(D) ≤ + 0.25, cylinder ≥ -0.25). Groups are subdivided into very low magnitudes of RE (0.50 and 0.75) and significant RE (1.00 ≤). Vision-related QOL was assessed using the Persian version of the 25-item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25). The NEI-VFQ was scored as visual function and socioemotional scales using Rasch analysis.

RESULTS

Corrected myopia, astigmatism, uncorrected myopia, and hyperopia had a lower vision-related QOL than emmetropes. (P < 0.001). Vision-related QOL in myopic subjects was lower than that in astigmatic participants. Very low myopes, who often do not use correction, had a significantly lower QOL than other groups.

CONCLUSION

Individuals with refractive errors experience a lower QOL score than those without. Notably, the adverse impact on QOL score is significantly greater in myopic cases, particularly very low myopia, compared to other refractive errors. Therefore, it is strongly recommended not to neglect managing very low myopia since it may improve participants' QOL.

Prevalence of myopia in school-age children in Ethiopia: A systematic review and meta-analysis

Objective

This study aimed to estimate the pooled prevalence of myopia among school-age children in Ethiopia.

Methods

Eligible articles were searched from PubMed, Embase, and Web of Science databases. In addition, Google Scholar and reference lists of the retrieved articles were searched from 30 July 2022 to 02 January 2023. The preferred reporting of items for systematic reviews and meta-analysis was used to report the search results. Microsoft Excel was used to keep the data. The qualities of eligible studies were checked using the Joanna Briggs Institute critical appraisal checklist for prevalence studies. Analysis was held using STATA Version 11. The degree of heterogeneity was checked using I² statistics. The possible sources of heterogeneity were examined using meta-regression and subgroup analyses. The funnel plot and Egger's test were used to assess the potential publication bias. A correction was made for publication bias using Duval and Twee Die's trim-and-fill analysis. The systematic review registration number is PROSPERO (#CRD42022330541).

Results

We identified 21 eligible articles including 20,757 subjects. Of those participants, 10,601 (51.1%) and 10,156 (48.9%) were males and females, respectively. A total of 15,152 (73%) participants were urban residents. The estimated prevalence of myopia among school-age children in Ethiopia was found to be 5.26% (95% confidence interval: 4.09-6.42).

Conclusions

The prevalence of myopia among school-age children in Ethiopia is considerable, affecting one in 20 school-age children. Therefore, the authors recommend the stakeholders take extra steps to speed up the implementation of the school vision screening program and its integration plan into the existing school nutrition program.

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

PURPOSE

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

DESIGN

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The prevalence of refractive errors in college students in Israel

PURPOSE

To determine the prevalence of refractive errors in Jewish and Arab college students in Israel and associations with ethnicity and sex.

METHODS

In this retrospective cross-sectional study, first-year college students underwent non-cycloplegic autorefraction and answered a questionnaire to assess age, sex, and self-identified ethnicity. Spherical equivalent refractive error (SER) was calculated, and the prevalence of hyperopia (>+0.50 Diopter, D), emmetropia (>-0.50 to +0.50 D), myopia (≤-0.50D, low ≤-0.50 to >-3.0D, moderate <-3.0 to >-6.0D, high ≤-6.0D), and astigmatism (>0.50D) were determined. Groups were compared using Chi-square or Fisher test. Univariate and multivariate analyses were conducted to identify factors associated with refractive errors.

RESULTS

Participants (n = 807) had a mean age of 22.1 ± 2.6 years (range: 17-30 years) and SER of -1.7 ± 2.2D (range: -13.3 to +5.7D). The prevalence and 95% confidence internal of myopia was 66.3% (63.0-69.6). Jewish students had a higher prevalence than Arab students for myopia (69.2% vs 60.3%), moderate (18.5% vs 12.2%) and high myopia (5.9% vs 1.9%) and astigmatism (51.4% vs 43.9%, p<0.05 for all), but not low myopia or hyperopia. Females had a higher prevalence of myopia than males (68.1% vs 58.7%, p<0.03). Jewish ethnicity was associated with myopia (OR=1.48, p = 0.01) and moderate myopia (OR=1.72, p = 0.01), and studying optometry was associated with moderate myopia (OR=1.63, p = 0.02). Sex and age were not associated with myopia.

CONCLUSION

Myopia prevalence in Israeli college students is high, showing associations with Jewish, but not Arab, ethnicity, suggesting that ethnic factors may play a role in the refractive differences between Arabs and Jews.

Astigmatism profile in the elderly population: Tehran Geriatric Eye Study

PURPOSE

To determine the prevalence of astigmatism and its associated factors and examine astigmatism symmetry patterns in an elderly population.

STUDY DESIGN

Population based cross-sectional study.

METHODS

The present population-based cross-sectional study was conducted on an elderly population above 60 years of age in Tehran, Iran in 2019. The sampling was done using the stratified multistage random cluster sampling method. All study participants underwent a complete optometric examination and slit-lamp biomicroscopy.

RESULTS

The prevalence of astigmatism higher than -0.50, -1.00, and -2.00 D was 83% (95% CI: 81 -84), 52 % (95% CI: 50 -54), and 19% (95% CI: 17-20), respectively. These prevalence was 79%(95% CI: 77-81), 46(95% CI: 44-49) and 14(95% CI: 13-16) in subjects without a history of ocular surgery, respectively. Based on cylinder power worse than -1.00 D, 10% (95% CI: 9-12), 20% (95% CI: 18-22), and 21% (95% CI:19-23) of study participants had with the rule, against the rule, and oblique astigmatism, respectively. According to the results of the multiple regression model, male gender, older age, low education level, pure posterior subcapsular cataract, pseudophakia, and myopia were independent factors associated with astigmatism. The prevalence of anisorule astigmatism was 57 % (95% CI: 56-59), the most common anisorule astigmatism was against the rule-oblique type with a prevalence of 36% (95% CI: 34-38).

CONCLUSION

The prevalence of astigmatism was high in the elderly population of Tehran. More than half of the participants in this study had anisorule astigmatism, and against the rule-oblique combination was more prevalent than other types. A posterior subcapsular cataract, a history of cataract surgery, and myopia were the associated factors of astigmatism in this study.

Refractive errors in a large dataset of French children: the ANJO study

Undetected refractive errors (REs) in children can lead to irreversible vision loss. This study aimed to show the proportions of REs in French children using cycloplegic refraction. Multicentre cross-sectional retrospective study including children with cycloplegic refraction and without associated ocular conditions from 2015 to 2018 in French eye clinics. The following data were collected: age, symptoms of eye strain, best-corrected visual acuity (BCVA), cycloplegic refraction. The analysis included 48,163 children (mean age: 7.75 years, range: 2 to 12 years). The proportion of each RE was as follows: emmetropia (− 0.50 < Spherical Equivalent (SE) ≤  + 2.0; 58.3%), hyperopia (+ 2.0 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$<$$\end{document}< SE \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\le$$\end{document}≤+5; 17.2%), myopia (− 6 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\le$$\end{document}≤ SE \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\le$$\end{document}≤− 0.50; 15.5%), high myopia (SE < − 6; 0.5%), high hyperopia (SE >  + 5; 3.6%), mixed astigmatism (4.9%). Anisometropia (SE difference ≥ 1.5) was found in 5.0%. Functional amblyopia in children attending primary school (aged over 6 years) was encountered in 2.7%. Symptoms of eye strain were frequent (70%) but not specific to any RE. REs are frequently found in French children and may remain undetected in the absence of symptoms of eye strain. Few studies have investigated REs in children using cycloplegic refraction, which has been shown to be the gold standard for RE assessment.

Prevalence of refractive errors among school students in Ethiopia: A systematic review and meta-analysis

Objective:

Refractive errors are most common ocular disorders among children and adolescents. They remain as secondary causes of avoidable blindness in impoverished areas in Africa, most notably in Ethiopia. The problem worsens if it is not managed and addressed early. The aim of this systematic review and meta-analysis was to determine the prevalence of refractive errors among school students in Ethiopia.

Methods:

We searched international databases such as PubMed/Medline, Web of Science, CINAHL, Embase, Scopus, Cochrane Library, Google Scholar, and Science Direct for relevant articles. Data were extracted using Microsoft Excel and exported to Stata version 14.0 software for analysis. The Cochrane Q and I2 tests were used to assess heterogeneity. Funnel plot, Egger’s, and Begg’s tests were used to assess reporting bias. Random effect meta-analysis model was employed to estimate pooled prevalence of refractive errors. A regional subgroup analysis was carried out.

Results:

We reviewed 22 qualified studies with 23,355 study participants. The overall prevalence of refractive errors among school students was 7.36% (95% confidence interval = 6.05, 8.67). The prevalence of myopia, hyperopia, and astigmatism was 5.10% (95% confidence interval = 3.79, 6.40), 0.95% (95% confidence interval = 0.59, 1.31), and 0.01% (95% confidence interval = 0.01, 0.04), respectively. From subgroup analysis, the highest prevalence of refractive errors was reported in Amhara Region (9.18%, 95% confidence interval = 6.63, 11.74), followed by Southern Nations, Nationalities, and Peoples’ region (6.78%, 95% confidence interval = 4.65, 8.92) while the lowest prevalence of refractive errors was reported in Addis Ababa (3.93%, 95% confidence interval = 3.30, 4.56).

Conclusion:

In Ethiopia, the prevalence of refractive errors among school students is higher (7.36%) compared to what it was 5 years (7.05%) ago. Amhara Region has the highest prevalence of refractive errors among school students in Ethiopia with myopia being the most common type of refractive error.

Prevalence and risk factors for myopia and high myopia: A cross-sectional study among Han and Uyghur students in Xinjiang, China

PURPOSE

This study aimed to investigate the prevalence and risk factors for myopia and high myopia among Han and Uyghur students in Xinjiang, China.

METHODS

This cross-sectional study with a multistage, stratified cluster sampling method was completed in Xinjiang, China. Visual acuity and noncycloplegic refraction were measured. The crude and sex- and age-adjusted prevalence of myopia and high myopia in Han and Uyghur students were compared. Multivariate logistic regression analyses were applied to identify risk factors associated with myopia and high myopia.

RESULTS

In total, 84,033 participants were included in the final analysis, comprising 64,110 Han and 19,923 Uyghur participants. The overall age- and sex-adjusted prevalence of myopia and high myopia were 47.70% (95% CI: 47.67-47.74) and 2.55% (95% CI: 2.54-2.56), respectively. Compared to the Uyghur population, the Han population had a higher prevalence of myopia (63.59% vs. 21.34%, p < 0.0001) and high myopia (4.68% vs. 0.6%, p < 0.0001). Han ethnicity, age, female sex, higher education level and living in urban areas were found to be positively associated with myopia and high myopia. Living in northern Xinjiang was found to be positively associated with myopia but negatively associated with high myopia.

CONCLUSIONS

Our study investigated the prevalence of myopia and high myopia among Han and Uyghur students aged 4-23 years in Xinjiang, China. The Han population had a higher prevalence of myopia and high myopia than the Uyghur population. However, the prevalence of myopia among the Uyghur population showed a more remarkable increasing trend than that among the Han population in Xinjiang.

Barriers and Perception Towards Spectacle Wear among a Student Population of University of Buraimi, Oman

Objectives

The study aimed to evaluate the barriers and perceptions towards spectacle wear among the student population of the University of Buraimi, Oman.

Methods

A descriptive, questionnaire-based and cross-sectional study was conducted between December 2017 and May 2018. Ophthalmic examination and a standard spectacle prescription protocol were used to identify those with inappropriate spectacle coverage. A self-designed and expert validated English-language questionnaire was utilised. A chi-square test was used to assess the association between the participants’ types of perceptions and sociodemographic and refractive error-related profiles.

Results

In total, 275 students participated in the study (response rate: 17.19%) and 170 (61.8%) were having inappropriate spectacle correction. Only 26% of them used spectacles since the majority (73.5%) had never had their eyes examined before this study. Most perceived spectacle wear positively (53.5%), followed by some having negative (36.5%) or neutral (10.0%) perceptions. Those from a health science background including Nursing and Optometry had a higher positive perception towards spectacle wear than others (P = 0.012). The difference in the perception scores between myopic and hypermetropic refractive error groups was statistically insignificant (P = 0.882).

Conclusion

The majority of the participants had had inappropriate vision corrections with spectacles and not undergone any prior ocular examinations. Few wore spectacles; however, these were inappropriate given their current refractive status. The reasons for spectacle non-wear were that either new spectacles had been ordered or spectacles were lost or broken. It is recommended that the school eye health initiative be extended to the university level. A holistic eye-health promotional approach toward integrating students, teachers and parents into this initiative can improve spectacle wear within the studied population.

Opportunities and threats to contact lens practice: A global survey perspective

AIM

To understand the views of contact lens (CL) practitioners across the globe regarding what they perceive as opportunities and threats in CL practice.

METHODS

A self-administered anonymised questionnaire, constructed in English and translated in six more languages, was distributed through reputed international professional bodies and academic institutions worldwide. The questionnaire included items on demographic characteristics, type of practice, and questions designed to explore practitioners' perspective on the future of their CL practice over the next five years.

RESULTS

A total of 2408 valid responses were analysed. Multifocal CLs for presbyopia, CLs for myopia control, use of daily disposable (DD) CLs for occasional wear, and biocompatible materials to improve comfort were identified as promising areas of opportunities by practitioners (all 8/10). Respondents from North America, and Europe valued DDCLs for occasional wear moderately more favourable (Median: 9/10 for all) as compared to colleagues in Asia (Median: 8/10, p < 0.001), South America (Median: 8/10, p < 0.01), and Africa (Median: 8/10p < 0.01). Multifocal CLs for presbyopia was perceived as a better opportunity by practitioners in North America and Europe (Median: 9/10 for both), as well as in Australasia (Median: 8/10), in comparison to Asia, Africa, and Middle East (for all Median: 6/10, p < 0.001). Practitioners expressed concerns about the availability of CLs and CL prescriptions online without direct professional involvement (both 9/10).

CONCLUSIONS

Overall, the most appealing opportunities for CL practice growth were identified in occasional use of DD CLs, biocompatible materials to reduce CL discomfort, multifocal CLs for presbyopia correction and management of myopia control with CLs. Lack of regulation in CL sales, especially online, seemed to be a constant threat. The insights from this study can be used to design targeted strategies to enhance CL practice across the globe and in specific geographical areas.

Prevalence of Prescription Glasses in the First-Grade Thai Students (7-8 Years Old)

PURPOSE

To study the prevalence of the prescription glasses given to first-grade students due to the "Good Sight for Thai Children" (GSTC) policy.

METHODS

This was a cross-sectional study that examined all prescription glasses given to first-grade students throughout Thailand, after visual screening due to the GSTC policy between 2016 and 2017. Trained class teachers screened their students' visual acuity and referred children who had less than 20/40 visual acuity in either eye to a hospital for an eye examination and prescription glasses.

RESULTS

A total of 786,729 students were screened. Of these, 20,401 (2.59%) students were referred to hospital. However, only 9867 (48.37%) students presented to a hospital. Glasses were prescribed for 5324 (53.96%) students following cycloplegic refraction by ophthalmologists or trained refractionists. The mean spherical equivalent was -1.08 (-19.00 to +10.00, SD 2.32) diopters. There were 1626 (30.54%) children at amblyopic risk without glasses. A 5.49% had high myopia (< -6 diopters), 5.22% had high hyperopia (> +5 diopters) and 27.82% had high astigmatism (>2 diopters). A cylindrical lens analysis showed that 81.53% had with-the-rule astigmatism, 4.07% had against-the-rule astigmatism, and 14.40% had oblique astigmatism.

CONCLUSION

Although the reliable prevalence of refractive error cannot be estimated, the prevalence of visual impairment may be estimated. There were a number of students who required glasses. The astigmatism was the most common refractive error on prescription glasses for first-grade children. With-the-rule astigmatism was the most prevalent. The visual screening program of school children proved to be valuable and should be continued and developed.

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.

Analysis of Tear Ferning Patterns in Young Female Subjects with Refractive Errors

To evaluate the dry eye symptoms and ocular tear film in young female subjects with refractive errors (RE) using the ocular surface disease index (OSDI), phenol red thread (PRT) and tear ferning (TF) tests. Methods. A group of 50 young female subjects (mean ± standard division = 20.3 ± 1.1 years) with RE (−0.25 to −6.00D) completed the study. An age-matched control group consisting of 50 healthy normal eye female subjects (22.2 ± 1.5 years) was recruited for comparison. The OSDI was completed first, followed by PRT and TF tests. Results. Median OSDI and TF scores were significantly higher (Mann–Whitney test; P < 0.001) among the study group subjects [median (interquartile range (IQR)) = 13.5 (15.3) and 1.6 (1.3), respectively] compared to the control group [6.0 (4.0) and 0.9 (0.8), respectively], whereas the median PRT score was significantly lower (Mann–Whitney test; P=0.003) in the study group [(27.5 (6.3) mm] compared to the control group [29.5 (5.0) mm]. For subjects within the mild RE group (N = 30), significant differences (Mann–Whitney test, P < 0.001 to 0.005) were found between the median OSDI, PRT, and TF scores and those recorded within the control group. For the subjects with moderate RE (N = 20), significant differences (Mann–Whitney test, P < 0.001 to 0.002) were found between the median OSDI and TF scores, and those recorded within the control group. Conclusion. The presence of RE in young females has a negative effect on tear film in terms of dry eye symptoms, tear volume, and TF grades. Dry eye symptoms experienced by subjects with RE and the TF grades were significantly higher compared with the control group. In addition, the tear volume was significantly lower in the study group. Clearly, RE has a risk factor for dry eye.

Types and Presentation of Refractive Error among Individuals Aged 0-30 Years: Hospital-Based Cross-Sectional Study, Yemen

BACKGROUND

Refractive errors are the most common cause of visual impairment worldwide. Its proportion varied among societies and is considered as a public health challenge. Symptoms and signs associated with refractive errors are the most worrisome and common presentations in the general practice in eye clinics.

AIM

The goal of this study was to determine the types and presentations of refractive error among the 0-30-year-old Yemeni population to aid early identification, diagnosis, referral, and treatment. Methodology. A cross-sectional study including 1,500 out-patients aged from 0 to 30 years attending the ophthalmology clinic in Sanaa, Yemen (between 2012 and 2015). All patients underwent visual acuity examination, autorefractometer, and anterior and posterior segment examination and were grouped according to type, that is, myopia, hyperopia, and astigmatism.

RESULTS

Hyperopia was the most common single diagnosis (53.3%) followed by myopia (33.3%). Astigmatism was uncommon as a single diagnosis (13.4%) but commonly associated with hyperopia or myopia. Myopia was more common in males (42.9%) than in females (25%). Hyperopia was more in females (62.5%) than in males (42.9%). Age groups most affected by refractive errors were 13-18 years (27.7%), 19-24 years (24.8%), and 25-30 years (24.6%), respectively. Decreased vision (53%) was a common presentation in myopia and astigmatism (41.5%) and less in hyperopia (39.6%). Headache was common in astigmatism (56%), hyperopia (28.8%), and myopia (17.8%). Muscle imbalance, namely, exotropia (27.2%), is mainly found in myopia and esotropia (24.3%) in hyperopia.

CONCLUSIONS

In addition to decreased vision, our patients with refractive errors mostly complain of headaches with clear variations with age and type of refractive error. Early identification and proper categorization of refractive errors by age, gender, and other demographics by general physicians in primary care can better deduce and make useful referrals to eye specialists.