Prevalence and causes of functional low vision in school-age children: results from standardized population surveys in Asia, Africa, and Latin America

Prevalence of visual impairment and associated factors among primary school children in Ambo Town, Ethiopia, 2021

Background

Visual impairment is a functional limitation of the eye(s) or the visual system manifested as reduced visual acuity. At least 2.2 billion people have visual impairment worldwide, and 90% of people with visual impairment have either preventable or treatable causes with cost-effective interventions.

Objectives

To assess magnitude of visual impairment and associated factors among primary school children in Ambo Town, Ethiopia, in 2021.

Methods

A cross-sectional study was conducted in selected primary schools of Ambo Town. A simple random sampling technique was used to select schools and study participants. Data were collected using an interviewer-administered structured questionnaire and entered into Epidata version 3.1 for analysis by using SPSS version 23. Binary logistic regression was adopted to identify statistically significant factors which were associated with visual impairment. The Hosmer-Lemeshow test was used to evaluate how well the logistic regression model fits to the data.

Results

About 780 out of 838 primary school children were enrolled in the study, yielding a response rate of 93.07%. The estimated prevalence of visual impairment was 8.8% with 95% CI: 6.81-10.79. The main risk factor for visual impairment among primary school children were Students' grade level, exposure to mobile screen, family history of visual problems, and family awareness about the status of their child's eye problems were significantly associated with visual impairments (AOR = 2.375, 95% CI: 1.079-5.226; AOR = 2.44, 95% CI: 1.401-5.01; AOR = 2.41, 95% CI: 1.071-5.42; and AOR = 4.503, 95% CI: 2.12-9.55, respectively).

Conclusion

A high prevalence of visual impairment was observed among primary school children. Attending higher grades, being exposed to mobile screen, and having a family history of visual problems were significantly associated with visual impairment.

Exploring Pediatric Vision Care: Insights from Five Years of Referral Cases in the UCI Eye Mobile and Implications of COVID-19

PURPOSE

To analyze referral rates, patient demographics, referral indications, and the impact of socioeconomic factors on ocular health from the University of California Irvine (UCI) Eye Mobile for Children, particularly during the coronavirus disease 2019 (COVID-19) pandemic.

METHODS

A retrospective chart review was performed on de-identified records of children examined on the UCI Eye Mobile. GraphPad Prism 10.0.0 and Python software were used for statistical analyses.

RESULTS

In the academic years from 2018 to 2022, 3,619 children received comprehensive eye examinations on the UCI Eye Mobile. Among them, 76 were referred to a pediatric ophthalmologist. The majority of these children were Hispanic (72.6%, 54 of 74), followed by Asian (10.9%, 8 of 74). A significant proportion (82.9%, 63 of 76) attended school districts with median incomes below that of Orange County. Statistically significant differences were found in age (P = .001; pre-COVID: 3.98 ± 1.08 years vs COVID: 5.75 ± 2.92 years) and gender (P = .023; pre-COVID female: 31 of 41 vs COVID female: 15 of 32) between the pre-COVID and COVID years. Additionally, there were significant differences in the proportion of children with hyperopia with astigmatism between the pre-COVID and COVID years (P = .044; pre-COVID: 23 of 40 vs COVID: 12 of 35). The most common indications for ophthalmologist referrals were for strabismus evaluation/treatment (28.9%, 22 of 76), followed by abnormal cup-to-disc ratio (21.1%, 16 of 76).

CONCLUSIONS

The study highlights the pivotal role of the UCI Eye Mobile for children in identifying ocular conditions needing referrals to subspecialty care. The majority of children needing these referrals attended schools in lower economic communities. Additionally, the COVID-19 pandemic appears to have influenced the demographic and clinical characteristics. [J Pediatr Ophthalmol Strabismus. 20XX:X(X):XXX-XXX.].

Citation Network Analysis on the Influence of Vision on Academic Performance

BACKGROUND

Proper vision is absolutely critical to children's academic performance, as vision problems can drastically affect learning ability. Currently, the existing literature in this field is somewhat inconsistent and carries several controversies about the influence of vision on academic performance. In this study, citation networks were utilized in order to analyze the relationship between publications and authors, the most-cited publication, and the different research areas. Additionally, the most commonly utilized publication sources along with the most common research areas were also pinpointed.

METHODS

The aforementioned search was executed in the Web of Science database, with a time range beginning in 1941 and ending in 2022. In order to scrutinize the publications, VOSviewer, CiteSpace software, and the Citation Network Explorer were utilized for analysis about the most-cited publication and the different research areas.

RESULTS

Overall, 1342 papers were found in all fields along with 2187 citation networks. Moreover, 2020 was the year with the most publications, including 127 publications and 4 citation networks. Bull et al., published in 2008, was the most-cited work, reaching a citation index of 975. The clustering function managed to identity four groups with the most engaging research topics from researchers: motor visual skills, visual memory, the influence of vision on the different learning styles, and abnormal development of the visual system.

CONCLUSIONS

In the end, the topic with the greatest interest was the influence of visual motor skills on academic performance. Ideally, this paper will assist fellow researchers in quickly noting which topics are of greatest interest and how research in this area has evolved.

Prevalence of refractive errors in Nepalese children and adults: a systematic review with meta-analysis

CLINICAL RELEVANCE

Country-specific estimates of the prevalence of refractive errors are important to formulate national eye health policies for refractive care services.

BACKGROUND

The purpose of this study was to systematically synthesise available literature and estimate the prevalence of refractive errors in the Nepalese population.

METHODS

PubMed, Scopus, and Web of Science databases were systematically searched for articles on refractive errors and presbyopia published in English language until 27 September 2022. Population and school-based quantitative, cross-sectional prevalence studies and Rapid Assessment of Avoidable Blindness survey repository data were included. The quality of the included studies was assessed using the Newcastle Ottawa scale adapted for cross-sectional studies. Data extraction was performed with consensus among the reviewers. Meta-analysis of the prevalence was performed using the Random effects model to estimate the pooled proportions.

RESULTS

A total of 38 studies with 101 701 participants were included: 18 studies in children (n = 31 596) and 20 in adults (n = 70 105). In children, the estimated pooled prevalence of overall refractive errors was 8.4% (95% CI: 4.8 to 12.9) with myopia, hypermetropia and astigmatism prevalent in 7.1% (95% CI: 3.7 to 11.4), 1.0% (95% CI: 0.7 to 1.3) and 2.2% (95% CI: 0.9 to 3.9), respectively. In adults, the prevalence of refractive errors, uncorrected refractive errors, and uncorrected presbyopia were 11.2% (95% CI: 8.0 to 14.9), 7.3% (95% CI: 5.4 to 9.5) and 78.9% (95% CI: 69.1 to 87.3), respectively.

CONCLUSIONS

The pooled prevalence of refractive errors is relatively low while uncorrected refractive errors and presbyopia are high in Nepalese population suggesting a need for better access to refractive care services in the country. The paucity of quality evidence on prevalence of refractive errors, particularly in children, indicates a need for a well-designed population-based study to accurately estimate the current prevalence of refractive errors.

Myopia and its associated factors among pregnant women at health institutions in Gondar District, Northwest Ethiopia: A multi-center cross-sectional study

Background

Myopia is the most common form of uncorrected refractive error with a growing burden worldwide. It is the principal complaint of most women during pregnancy. Although myopia has led to several consequences across the standard life of pregnant women, there is no previous study in Ethiopia regarding this topic. Thus, this study determined the prevalence of myopia and identifies its associated factors among pregnant women attending antenatal care units at governmental health institutions in Gondar City District, Northwest Ethiopia.

Methods

An institution-based cross-sectional study design was conducted from 08 February to 08 April 2021. From the selected health centres, study participants were recruited by systematic random sampling technique. A pre-tested, structured-interviewer-administered questionnaire consisting of socio-demographic variables, obstetric and clinical-related variables was used to collect the required data. Non-cycloplegic refraction was performed using trial lenses, trial frames, and retinoscopy in a semi-dark examination room. EpiData 3 and STATA 14 were used for data entry and statistical analysis respectively. Both bivariable and multivariable binary logistic regression analyses were executed to identify associated factors of myopia. Variables with a p-value ≤0.05 in the multivariable logistic regression analysis were declared as statistically significant with myopia. Model fitness was checked by Hosmer and Lemeshow goodness of test (at p > 0.05).

Results

A total of four-hundred and twenty-three pregnant women participated with a 100% response rate in this study. The overall prevalence of myopia among pregnant women was 26.48% (95% CI: 22.48-30.91). Eighty-Eight (20.81%) and Eighty-Four (19.85%) of the study participants had myopia in their right and left eyes respectively. The prevalence of myopia was significantly associated with age (AOR = 1.17; 95% CI: 1.09-1.28), the third trimester of gestation (AOR = 2.05, 95% CI: 1.08-3.90), multi & grand multipara (AOR = 3.15; 95% CI: 1.59-6.25), and history of contraceptive use (AOR = 3.30; 95% CI: 1. 50-7.28).

Conclusion

The finding of our study shows that there is a higher prevalence of myopia among pregnant women in our study area. Further prospective analytical studies regarding visual systems among pregnant women, particularly as a result of pregnancy, are strongly recommended.

Visual impairment in Ethiopia: Systematic review and meta-analysis

WHO Prevention of Blindness Program launched ‘‘VISION 2020” in 1999 to reduce visual impairment and eradicate avoidable blindness by the year 2020. Ethiopia launched the “VISION 2020” initiative in 2002. This systematic review and meta-analysis aimed to present the national prevalence of visual impairment at the end of “VISION 2020”. Electronic search was conducted on the PubMed, SCOPUS, EMBASE, Web of Science, CINAHL, Google scholar databases for including articles. This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Endnote reference manager was used for downloading, organizing, and citing articles. Methodological quality was assessed using the Joanna Briggs Institute (JBI) quality appraisal tool for prevalence studies. Statistical analysis was done using the STATA™ software version 14. In this systematic review and meta-analysis, 18 studies involving 14,953 participants were included. The pooled prevalence of visual impairment in Ethiopia after correction for publication bias by Duval and Tweedie’s trim and fill analysis was estimated to be 6.24% (95% confidence interval [CI] = [2.66, 9.82]). The pooled prevalence of visual impairment among school children and adults in Ethiopia was 6.13% (95% CI = [4.27, 7.98]) and 19.89% (95% CI = [10.85, 28.93]), respectively. The most common causes of visual impairment in decreasing order of prevalence were refractive error, cataract, trachoma, glaucoma, and corneal opacity. Amblyopia was the cause of visual impairment among school-age child. The prevalence of visual impairment in Ethiopia was still significant at the end of “VISION 2020” program. Therefore, the program of “VISION 2020” should be extended and other large-scale programs were needed to reduce the prevalence of vision impairment in Ethiopia.

The prevalence and causes of pediatric uncorrected refractive error: Pooled data from population studies for Global Burden of Disease (GBD) sub-regions

Background

There are limited systematic reviews on the prevalence of uncorrected refractive errors in children. We aimed to summarize the prevalence and causes of pediatric uncorrected refractive error (URE) from studies in the Global Burden of Disease (GBD) sub-regions.

Methods

The pooled analysis used the individual participant data (ages less than 20 years old) from population-based studies around the world by regions. URE was defined as presenting VA < 6/18 and improving to ≥ 6/18 or ≥1 line on using a pinhole in either eye, with main causes of myopia, hyperopia or astigmatism. Each study provided data on any URE, myopia, hyperopia or astigmatism by age, gender, and ethnicity. Prevalence rates were directly age and gender standardized to the 2020 world population with all age groups. Estimates were calculated by study and sub-regions after pooling. Summary estimates included studies in which URE was assessed from a pinhole-corrected refraction in the better eye.

Results

The combined pooled data contained 302,513,219 patients including 8 963 URE cases individuals from 57 studies. Prevalence varied by age and GBD sub-regions and differed by gender. The age- and region-standardized prevalence of URE was 3.41 per 1000 (CI, 1.53~7.62) in Western Pacific region (12 studies), 2.26 per 1000 (CI, 0.85~6.01) in South-East Asia region (14 studies), 5.85 per 1000 (CI, 3.75~9.13) in Americans (11 studies) and 4.40 per 1000 (CI, 3.0~6.45) in Eastern Mediterranean region (13 studies). On the basis of these data, myopia was the first-leading cause in female children with 12~17 age group, with the prevalence rate 18.2 per 1000 (CI, 11.52~23.61). Astigmatism was detected in 27.2 per 1000 male children with 6~11 age group (CI: 19.12–30.68).

Conclusions

Prevalence of URE available data within these sub-regions are widely disparate. Myopia and astigmatism in young age children continue as the leading cause of URE worldwide. Providing appropriate refractive correction to those individuals whose vision can be improved is an important public health endeavor with implications for safety and quality of life.

Evaluation of the Blinq Vision Screener in the Detection of Amblyopia and Strabismus in Children

Purpose

Amblyopia is a major health problem with an estimated 2% to 4% of the population affected. Screening combined with corrective measures, such as correction of refractive error and occlusion of the dominant eye, could reduce this prevalence. A new pediatric vision scanner, the blinq (Rebion, Boston, MA), studies the foveolar quality of fixation of each eye during binocular viewing. Based on the initial premise that poor quality foveolar or non-foveolar fixation is indicative of strabismus and, potentially of amblyopia, this study evaluates the effectiveness of the blinq screening device in detecting these two conditions compared to a standard ophthalmic examination (Gold Standard) based on the recommendations of the American Association for Pediatric Ophthalmology and Strabismus.

Material and Methods

A prospective study was performed on a total of 101 children between 2 and 8 years of age. These children were offered a test by the blinq screening device before a standard ophthalmological examination in the ophthalmology department of the Erasmus Hospital in Brussels, Belgium. The two tests were then compared.

Results

In a pediatric population heightened with amblyopia and strabismus (prevalence of 33.4%) and based on the Gold Standard Examination, the blinq device showed a specificity of 73.1% (95% confidence interval [CI] = 60.9%–83.2%) with a sensitivity of 91.2% (95% CI = 76.3%–98.1) to detect these conditions. The positive and negative predictive values were 63.3% (95% CI = 53.4%–72.2%) and 94.2% (95% CI = 84.6%–98%) respectively. The positive likelihood ratio (LR+) was 3.39 (95% CI = 2.26–5.11) for a negative likelihood ratio of 0.12 (95% CI = 0.04–0.36).

Conclusions

The blinq device has good sensitivity, but insufficient specificity to be used alone in the first line of screening. Whereas other devices on the market detect risk factors that may lead to amblyopia, the blinq pediatric vision scanner detects poor foveolar fixation and strabismus, giving it a potential advantage in sensitivity to directly detect strabismus, including microstrabismus. The blinq does not detect refractive abnormalities, however, and will therefore need to be improved in the future to be used alone in pediatric vision screening.

Translational Relevance

The blinq device detects visual axis alignment abnormalities with potential impact in the early detection of strabismus and subsequent associated amblyopia.

Binocular versus standard occlusion or blurring treatment for unilateral amblyopia in children aged three to eight years

BACKGROUND

Current treatments for amblyopia, typically patching or pharmacological blurring, have limited success. Less than two-thirds of children achieve good acuity of 0.20 logMAR in the amblyopic eye, with limited improvement of stereopsis, and poor adherence to treatment. A new approach, based on presentation of movies or computer games separately to each eye, may yield better results and improve adherence. These treatments aim to balance the input of visual information from each eye to the brain.  OBJECTIVES: To determine whether binocular treatments in children, aged three to eight years, with unilateral amblyopia result in better visual outcomes than conventional patching or pharmacological blurring treatment.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register), MEDLINE, Embase, ISRCTN, ClinicalTrials.gov, and the WHO ICTRP to 19 November 2020, with no language restrictions.

SELECTION CRITERIA

Two review authors independently screened the results of the search for relevant studies. We included randomised controlled trials (RCTs) that enrolled children between the ages of three and eight years old with unilateral amblyopia. Amblyopia was classed as present when the best-corrected visual acuity (BCVA) was worse than 0.200 logMAR in the amblyopic eye, with BCVA 0.200 logMAR or better in the fellow eye, in the presence of an amblyogenic risk factor, such as anisometropia, strabismus, or both. To be eligible, children needed to have undergone cycloplegic refraction and  ophthalmic examination, including fundal examination and optical treatment, if indicated, with stable BCVA in the amblyopic eye despite good adherence with wearing glasses. We included any type of binocular viewing intervention, on any device (e.g. computer monitors viewed with liquid-crystal display shutter glasses; hand-held screens, including mobile phones with lenticular prism overlay; or virtual reality displays). Control groups received standard amblyopia treatment, which could include patching or pharmacological blurring of the better-seeing eye. We included full-time (all waking hours) and part-time (between 1 and 12 hours a day) patching regimens. We excluded children who had received any treatment other than optical treatment; and studies with less than 8-week follow-up.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. The primary outcome of the review was the change from baseline of distance BCVA in the amblyopic eye after 16 (± 2) weeks of treatment, measured in logMAR units on an age-appropriate acuity test.

MAIN RESULTS

We identified one eligible RCT of conventional patching treatment versus novel binocular treatment, and analysed a subset of 68 children who fulfilled the age criterion of this review. We obtained data for the mean change in amblyopic eye visual acuity, adverse events (diplopia), and adherence to prescribed treatment at 8- and 16-week follow-up intervals, though no data were available for change in BCVA after 52 weeks. Risk of bias for the included study was considered to be low. The certainty of evidence for the visual acuity outcomes at 8 and 16 weeks of treatment and adherence to the study intervention was rated moderate using the GRADE criteria, downgrading by one level due to imprecision. The certainty of evidence was downgraded by two levels and rated low for the proportion of participants reporting adverse events due to the sample size.  Acuity improved in the amblyopic eye in both the binocular and patching groups following 16 weeks of treatment (improvement of -0.21 logMAR in the binocular group and -0.24 logMAR in the patching group, mean difference (MD) 0.03 logMAR (95% confidence interval (CI) -0.10 to 0.04; 63 children). This difference was non-significant and the improvements in both the binocular and patching groups are also considered clinically similar. Following 8 weeks of treatment, acuity improved in both the binocular and patching groups (improvement of -0.18 logMAR in the patching group compared to -0.16 logMAR improvement in the binocular-treatment group) (MD 0.02, 95% CI -0.04 to 0.08). Again this difference was statistically non-significant, and the differences observed between the patching and binocular groups are also clinically non-significant. No adverse event of permanent diplopia was reported. Adherence was higher in the patching group (47% of participants in the iPad group achieved over 75% compliance compared with 90% of the patching group).  Data were not available for changes in stereopsis nor for contrast sensitivity following treatment.

AUTHORS' CONCLUSIONS

Currently, there is only one RCT that offers evidence of the safety and effectiveness of binocular treatment. The authors are moderately confident that after 16 weeks of treatment, the gain in amblyopic eye acuity with binocular treatment is likely comparable to that of conventional patching treatment. However, due to the limited sample size and lack of long term (52 week) follow-up data, it is not yet possible to draw robust conclusions regarding the overall safety and sustained effectiveness of binocular treatment. Further research, using acknowledged methods of visual acuity and stereoacuity assessment with known reproducibility, is required to inform decisions about the implementation of binocular treatments for amblyopia in clinical practice, and should incorporate longer term follow-up to establish the effectiveness of binocular treatment. Randomised controlled trials should also include outcomes reported by users, adherence to prescribed treatment, and recurrence of amblyopia after cessation of treatment.

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.

Visual impairment and associated factors among pregnant women attending antenatal care units at health institutions in Gondar City Administration, Northwest Ethiopia

Background

Visual impairment is a major public health concern among women of reproductive age groups in Ethiopia, which is getting worse during pregnancy. Though visual impairment has lots of serious consequences across the life course of pregnant women, there is no previous study on this topic in Ethiopia. Thus, this study determined the prevalence of visual impairment and identified associated factors among pregnant women attending antenatal care units at the governmental health institutions in Gondar City Administration, Northwest Ethiopia.

Methods

An institution-based cross-sectional study was conducted. A systematic random sampling technique was used to recruit the study participants. We used an interviewer-administered questionnaire comprising of socio-demographic, clinical and pregnancy-related variables to collect the required data. Snellen’s illiterate “E” chart was used to determine visual impairment. EpiData 3 and Stata 14 were used for data entry and statistical analysis, respectively. Both bivariable and multivariable binary logistic regression analyses were executed to identify associated factors of visual impairment. Variables with a p-value ≤0.05 in the multivariable logistic regression analysis were declared as statistically significant with visual impairment.

Results

A total of 417 (response rate = 98.6%) participants were involved in this study, with a median age of 27 years. The overall prevalence of visual impairment was 22.5% (95% CI: 18.5–26.6). Thirty (7.2%) and thirty-two (7.7%) of the study participants had moderate to severe visual impairments in their right and left eyes, respectively. Participants aged from 31 to 49 years (AOR = 2.1; 95% CI: 1.1–4.0), being 3rd trimester (AOR = 2.4; 95% CI: 1.3–4.5), multi & grand multipara (AOR = 2.3; 95% CI: 1.2–4.6), and history of contraceptive use (AOR = 2.7; 95% CI: 1.2–6.3) had higher chance of visual impairment.

Conclusion

The magnitude of visual impairment among pregnant women was high in the study area. Therefore, routine screening and evaluation of pregnant women for visual condition during antenatal care visits is recommended. Further investigations of visual changes, particularly as a result of pregnancy, are warranted.

Refractive error, risk of amblyopia and eye care services utilisation among Nunavik Inuit in Northern Canada

CLINICAL RELEVANCE

Nunavik Inuit patients, in Northern Canada, have a significant burden of refractive error. The frequency at which they access eye care is insufficient. This exposes children of this population to a substantial risk of refractive amblyopia.

BACKGROUND

No data are available on eye health and services among Nunavik Inuit in Quebec, Canada. This study aims to describe the prevalence of ametropias, risk of refractive amblyopia, and eye health services uptake amongst a sample of Nunavik Inuit.

METHODS

Retrospective cohort using data from electronic records of the sole government-contracted eye team travelling to all 14 Nunavik villages, from 2006 to 2018.

RESULTS

Some 26,541 examinations were analysed, with data from 6,341 patients (median age 27 years (IQR 30); 32% aged under 19 years; 60.3% female) representing 48% of the census population. Population weighted prevalence of ametropias was myopia 46.5% (95% CI 45.3 - 47.6), hyperopia 17.1% (95% CI 16.2 - 18.1), astigmatism 39.6% (95% CI 38.4 - 40.8) and presbyopia 30.0% (95% CI 28.9 - 31.0). Some 5.9% of patients aged 0-9 years present a risk of refractive amblyopia. Mean frequency of examinations for all ages was once per 4 years (95% CI 4.0 - 4.0) and for children aged 5 - 19 years, frequency was once per 4.8 years (95% CI 4.8 - 5.0). In 2018, 74% of patients who were prescribed spectacles purchased them, with a median time of procurement of 21 days (IQR 247, skewness 2.7).

CONCLUSION

There is a high prevalence of ametropias amongst the clinical population of Nunavik Inuit. Most patients needing spectacles obtain them within a few weeks. Frequency of eye health services is insufficient to meet recommended guidelines, especially in children, for whom the risk of refractive amblyopia is pervasive.

Causes of Blindness and Visual Impairment in Early Childhood at a Low Vision Service in Mexico City: A 15-year Review

Purpose: To evaluate the causes of blindness and visual impairment in children aged 0-7 years attending a Low Vision Centre in Mexico City, Mexico.Methods: Clinical records for patients aged 0-7 years attending the Centre from 2001 to 2015 were retrospectively reviewed. Causes of blindness and visual impairment, affected anatomy, and suspected time period of insult were recorded.Results: 1487 patients were included, 45.9% girls and 54.1% boys. Mean age of presentation was 39 months (SD 27.9 months). 36.0% had associated co-morbidities in addition to their ophthalmic pathology. 39.7% presented with developmental or psychomotor delay. Leading diagnoses were Retinopathy of Prematurity (ROP) (19.6%), optic nerve atrophy (11.5%), and congenital cataract (9.5%). The most affected anatomical regions were retina (33.8%), optic nerve (16.6%), and lens (10.5%). Half of all cases (50.9%) had insults in the prenatal period. Children with developmental delay were more likely to present before the age of one. There is a significant difference in risk of delayed presentation according to diagnosis. Only 13.5% of children with optic nerve atrophy presented to the Centre before the age of one, compared to 28.4% of children with ROP and 23.4% of children with cataract.Conclusion: The most common diagnoses for blindness and visual impairment among children were ROP, optic nerve atrophy, and congenital cataract. Late presentation to the Centre was common. There were significant differences in risk of delayed presentation depending on diagnosis. Co-existing systemic conditions and developmental and psychomotor delay were also common among patients attending the Centre.

Prevalence and causes of vision loss in China from 1990 to 2019: findings from the Global Burden of Disease Study 2019

BACKGROUND

Vision loss is an important public health issue in China, but a detailed understanding of national and regional trends in its prevalence and causes, which could inform health policy, has not been available. This study aimed to assess the prevalence, causes, and regional distribution of vision impairment and blindness in China in 1990 and 2019.

METHODS

Data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 were used to estimate the prevalence of moderate and severe vision impairment and blindness in China and compare with other Group of 20 (G20) countries. We used GBD methodology to systematically analyse all available demographic and epidemiological data at the provincial level in China. We compared the age-standardised prevalences across provinces, and the changes in proportion of vision loss attributable to various eye diseases in 1990 and 2019. We used two different counterfactual scenarios with respect to population structure and age-specific prevalence to assess the contribution of population growth and ageing to trends in vision loss.

FINDINGS

In 2019, the age-standardised prevalence was 2·57% (uncertainty interval [UI] 2·28-2·86) for moderate vision impairment, 0·25% (0·22-0·29) for severe vision impairment, and 0·48% (0·43-0·54) for blindness in China, which were all below the global average, but the prevalence of moderate and severe vision impairment had increased more rapidly than in other G20 countries from 1990 to 2019. The prevalence of vision loss increased with age, and the main causes of vision loss varied across age groups. The leading causes of vision impairment in China were uncorrected refractive error, cataract, and macular degeneration in both 1990 and 2019 in the overall population. From 1990 to 2019, the number of people with moderate vision impairment increased by 133·67% (from 19·65 to 45·92 million), those with severe vision impairment increased by 147·14% (from 1·89 to 4·67 million), and those with blindness increased by 64·35% (from 5·29 to 8·69 million); in each case, 20·16% of the increase could be explained by population growth. The contributions to these changes by population ageing were 87·22% for moderate vision impairment, 116·06% for severe vision impairment, and 99·22% for blindness, and the contributions by age-specific prevalence were 26·29% for moderate vision impairment, 10·91% for severe vision impairment, and -55·04% for blindness. The prevalence and specific causes of vision loss differed across provinces.

INTERPRETATION

Although a comprehensive national policy to prevent blindness is in place, public awareness of visual health needs improving, and reducing the prevalence of moderate and severe vision impairment should be prioritised in future work.

FUNDING

China National Key Research and Development Programme and Beijing Municipal Special Funds for Medical Research on Public Welfare Development and Reform.

Trends in prevalence of blindness and distance and near vision impairment over 30 years: an analysis for the Global Burden of Disease Study

BACKGROUND

To contribute to the WHO initiative, VISION 2020: The Right to Sight, an assessment of global vision impairment in 2020 and temporal change is needed. We aimed to extensively update estimates of global vision loss burden, presenting estimates for 2020, temporal change over three decades between 1990-2020, and forecasts for 2050.

METHODS

We did a systematic review and meta-analysis of population-based surveys of eye disease from January, 1980, to October, 2018. Only studies with samples representative of the population and with clearly defined visual acuity testing protocols were included. We fitted hierarchical models to estimate 2020 prevalence (with 95% uncertainty intervals [UIs]) of mild vision impairment (presenting visual acuity ≥6/18 and <6/12), moderate and severe vision impairment (<6/18 to 3/60), and blindness (<3/60 or less than 10° visual field around central fixation); and vision impairment from uncorrected presbyopia (presenting near vision <N6 or <N8 at 40 cm where best-corrected distance visual acuity is ≥6/12). We forecast estimates of vision loss up to 2050.

FINDINGS

In 2020, an estimated 43·3 million (95% UI 37·6-48·4) people were blind, of whom 23·9 million (55%; 20·8-26·8) were estimated to be female. We estimated 295 million (267-325) people to have moderate and severe vision impairment, of whom 163 million (55%; 147-179) were female; 258 million (233-285) to have mild vision impairment, of whom 142 million (55%; 128-157) were female; and 510 million (371-667) to have visual impairment from uncorrected presbyopia, of whom 280 million (55%; 205-365) were female. Globally, between 1990 and 2020, among adults aged 50 years or older, age-standardised prevalence of blindness decreased by 28·5% (-29·4 to -27·7) and prevalence of mild vision impairment decreased slightly (-0·3%, -0·8 to -0·2), whereas prevalence of moderate and severe vision impairment increased slightly (2·5%, 1·9 to 3·2; insufficient data were available to calculate this statistic for vision impairment from uncorrected presbyopia). In this period, the number of people who were blind increased by 50·6% (47·8 to 53·4) and the number with moderate and severe vision impairment increased by 91·7% (87·6 to 95·8). By 2050, we predict 61·0 million (52·9 to 69·3) people will be blind, 474 million (428 to 518) will have moderate and severe vision impairment, 360 million (322 to 400) will have mild vision impairment, and 866 million (629 to 1150) will have uncorrected presbyopia.

INTERPRETATION

Age-adjusted prevalence of blindness has reduced over the past three decades, yet due to population growth, progress is not keeping pace with needs. We face enormous challenges in avoiding vision impairment as the global population grows and ages.

FUNDING

Brien Holden Vision Institute, Fondation Thea, Fred Hollows Foundation, Bill & Melinda Gates Foundation, Lions Clubs International Foundation, Sightsavers International, and University of Heidelberg.

Low vision evaluation training in Nigeria: Time to improve human resource in developing countries

Routine low vision care is a rarity in Nigeria and in most developing countries. The reason for the widespread apathy and lack of human resource development in this area is myriad. The Center for Vision, The Lens Rehabilitation Center for the Blind located in Portharcourt, Nigeria sought to correct this by working to revive interest and thus improve human resource available through provision of quality hands on training with world renowned scholars and faculty . Records of all who registered for two separate Low vision training courses at TLEC re(Hab) Nigeria between 2018 and 2019 were audited. Number of courses taught, participating faculty, gender and age distribution of trainees, previous training accessed by trainees, pretest scores and post test scores were compared. Numbers actually practicing low vision after 3 months of conclusion of the training and outcome of feedback questionnaires were also evaluated using a simple calculator. Fifty eyecare workers (42 in one day training and 8 over 2 weeks) with mean age of 33.6years and gender ratio of 1:2.3 were trained in two batches. There were 26 faculty available to teach both online and physically. Previous exposure to training was absent in the one day group while the two week group had just one. The courses taught were mainly on low vision evaluation(50% in the one day , 44.29% in the 2 week course) with additional courses on early intervention, rehabilitation of the blind and evaluation in special kids with additional problems. The hands on sessions were significantly better in the two week training with a third of the periods available dedicated to stepwise approach in low vision evaluation.

A comparison of pretest and post test scores showed there was an exponential improvement in understanding between the one day and the two week training of up to 50 % increase which reflected in the numbers able to refer appropriately and evaluate low vision patients in the country when the one day and 2 week groups were compared. There was a general consensus that the two week training was more preferred. Empowerment with relevant low vision charts and device equipment significantly improved the numbers still practicing 3 months after training ended when compared with those who were not given any by as much as 400%. In conclusion, low vision needs dedicated and well trained staff who compulsorily need to be empowered to function with provision of required equipment especially in developing countries where the majority of the need for low vision aids and assistive devices appear to be.

A profile of patients presenting at a low vision clinic in a resource-limited setting

Background: The university-based low vision clinic is one of the few low vision clinics in South Africa.Aim: To describe demographic and clinical profiles of patients who attended this clinic from 2010 to 2017.Setting: The university low vision clinic, South Africa.Methods: The record cards of all patients seen at the low vision clinic over 8 years were examined and the following information was extracted: age, gender, presenting visual acuity (VA), VA following low vision assessment, cause of visual impairment and types of low vision devices recommended.Results: A total of 621 patients were examined, comprising 45.1% males and 55.9% females aged 36.0 ± 18.2 years (range: 4–93 years). Many of these patients (33.7%) had presenting VA worse than 1.3 logarithm of the Minimum Angle of Resolution (logMAR) ( 6/120) at 4 m in the better eye, and 196 (31.6%) had presenting VA of worse than 1.3 logMAR at near distance. Following optical low vision assessment, 62.4% had distance VA of 0.9 LogMAR (6/48) to −0.2 logMAR (6/3.8) and 58.4% had near VA of 0.9 logMAR (6/48) to −0.2 logMAR (6/3.8). Albinism (22.7%), unknown causes (18.2%), cataract (15.5%) and macular diseases (12.2%) were the most common causes of low vision. Amblyopia (80.7%) was the most common cause of low vision in patients aged 20 years and younger, followed by albinism (68.1%) and corneal diseases (41%). Cataract (78.1%), macular diseases (64.4%) and glaucoma (55.9%) were the most common causes of low vision in patients aged more than 60 years. Telescopes (33.8%) were the most commonly recommended form of intervention, followed by magnifiers (29.6%) and protective measures (24.5%).Conclusion: Albinism, cataract and macular diseases are the predominant causes of low vision in patients attending this low vision clinic. There was a significant improvement in VA after low-vision assessment, particularly for patients with presenting VA of better than 1.3 logMAR (6/120).

Prevalence of Visual Impairment and Associated Factors Among Primary Schoolchildren in Addis Ababa, Central Ethiopia

BACKGROUND

Visual impairment (VI) refers to reduction of vision resulting in a lower than normal visual acuity (VA). Although school programs are recommended for early detection and timely interventions of VI, available information with regard to prevalence of VI and associated factors among primary schoolchildren near to the main city, Addis Ababa is inadequate. Thus, we assessed the prevalence of VI and the associated factors among children attending government primary schools of Lideta sub-city, Addis Ababa, Ethiopia.

METHODS

This was a school-based cross-sectional study conducted from April to May 2019, using a two-stage cluster sampling method in Lideta sub-city, Addis Ababa, Ethiopia. From the total 18 government primary schools in Lideta sub-city, six were selected using probability proportionate to size (PPS) method. The study population was primary schoolchildren aged 7 to 17 years in the selected six primary schools. A total of 816 eligible primary schoolchildren were identified to be included in the study. The selected children were examined for the presence of VI. Children's parents/guardians were interviewed using structured pre-tested questionnaires. In this study, myopia and hyperopia were defined as difficulty in viewing distant and near objects, respectively. Similarly, astigmatism was a refractive error which results from an uneven cornea surface, which results in distorted images. Epi-data 3.1 and SPSS version 20 were used for data entry and analysis, respectively. Binary logistic regression was performed to check association between dependent and independent variables. Significance was set at p-value <0.05.

RESULTS

From a total of 816 eligible primary schoolchildren, 773 children were examined for VI, making the response rate 94.7%. Out of the 773 children, 370 (47.9%) were male and 403 (52.1%) were female. The mean age of the participants was 11.69 years (SD 2.64 years). The prevalence of VI among schoolchildren was 4.4%. The causes of VI included myopia (43%), astigmatism with or without amblyopia (31%), hyperopia with or without amblyopia (20%), and others. The parents/guardians not being aware of their children's eye problem (AOR=2.2, 95% CI: 1.2-4.4) was the only significantly associated factor with VI.

CONCLUSION

In this study, the prevalence of VI among schoolchildren was high. The students being unaware about their eye problem was significantly associated with VI. Thus, close monitoring and regular screening for VI in schoolchildren are highly recommended to allow timely intervention.

Long-term visual and treatment outcomes of whole-population pre-school visual screening (PSVS) in children: a longitudinal, retrospective, population-based cohort study

BACKGROUND

This study reports the long-term visual and treatment outcomes in a whole-population, orthoptic-delivered pre-school visual screening (PSVS) programme in Scotland and further examines their associations with socioeconomic backgrounds and home circumstances.

METHODS

Retrospective case review was conducted on 430 children who failed PSVS. Outcome measures included best corrected visual acuity (BCVA), severity of amblyopia (mild, moderate and severe), binocular vision (BV) (normal, poor and none), ophthalmic diagnosis and treatment modalities. Parameters at discharge were compared to those at baseline and were measured against the Scottish index of multiple deprivation (SIMD) and Health plan indicator (HPI), which are indices of deprivation and status of home circumstances.

RESULTS

The proportion of children with amblyopia reduced from 92.3% (373/404) at baseline to 29.1% (106/364) at discharge (p < 0.001). Eighty percent (291/364) had good BV at discharge compared to 29.2% (118/404) at baseline (p < 0.001). Children from more socioeconomically deprived areas (OR 2.19, 95% CI 1.01-4.30, p = 0.003) or adverse family backgrounds (OR 3.94, 95% CI 1.99-7.74, p = 0.002) were more likely to attend poorly and/or become lost to follow-up. Children from worse home circumstances were five times more likely to have residual amblyopia (OR 5.37, 95% CI 3.29-10.07, p < 0.001) and three times more likely to have poor/no BV (OR 3.41, 95% CI 2.49-4.66, p < 0.001) than those from better home circumstances.

CONCLUSIONS

Orthoptic-delivered PSVS is successful at screening and managing amblyopia. Children from homes requiring social care input are less likely to attend and are more likely to have poorer visual outcomes.

Low availability of choline in utero disrupts development and function of the retina

Adequate supply of choline, an essential nutrient, is necessary to support proper brain development. Whether prenatal choline availability plays a role in development of the visual system is currently unknown. In this study, we addressed the role of in utero choline supply for the development and later function of the retina in a mouse model. We lowered choline availability in the maternal diet during pregnancy and assessed proliferative and differentiation properties of retinal progenitor cells (RPCs) in the developing prenatal retina, as well as visual function in adult offspring. We report that low choline availability during retinogenesis leads to persistent retinal cytoarchitectural defects, ranging from focal lesions with displacement of retinal neurons into subretinal space to severe hypocellularity and ultrastructural defects in photoreceptor organization. We further show that low choline availability impairs timely differentiation of retinal neuronal cells, such that the densities of early-born retinal ganglion cells, amacrine and horizontal cells, as well as cone photoreceptor precursors, are reduced in low choline embryonic d 17.5 retinas. Maintenance of higher proportions of RPCs that fail to exit the cell cycle underlies aberrant neuronal differentiation in low choline embryos. Increased RPC cell cycle length, and associated reduction in neurofibromin 2/Merlin protein, an upstream regulator of the Hippo signaling pathway, at least in part, explain aberrant neurogenesis in low choline retinas. Furthermore, we find that animals exposed to low choline diet in utero exhibit a significant degree of intraindividual variation in vision, characterized by marked functional discrepancy between the 2 eyes in individual animals. Together, our findings demonstrate, for the first time, that choline availability plays an essential role in the regulation of temporal progression of retinogenesis and provide evidence for the importance of adequate supply of choline for proper development of the visual system.-Trujillo-Gonzalez, I., Friday, W. B., Munson, C. A., Bachleda, A., Weiss, E. R., Alam, N. M., Sha, W., Zeisel, S. H., Surzenko, N. Low availability of choline in utero disrupts development and function of the retina.

Assistive technology for students with visual disability in schools for the blind in Delhi

Background: To understand the awareness and utilization of assistive technology in students at schools for the blind in Delhi.Methods: A cross sectional study was conducted among 250 students selected randomly from 10 blind schools in Delhi. Binocular distance presenting and pinhole vision acuity were assessed using Snellen "E" chart and a multiple pinhole occluder. Students were also interviewed using a questionnaire about 42 assistive devices to understand their awareness and use.Results: Male participants were 72.8%. Of the total, 27.6% students had best corrected visual acuity <6/18 to 1/60, and the rest had <1/60 vision. The awareness about tactile and sound-based technology was good among students: Braille books (98%), Braille slate and stylus (99.2%), handheld audio recorders (77.6%) and screen readers (77.2%). Good awareness was reported for abacus (88.8%), walking long canes (94.4%) and smart cane (89.6%), audible balls (96%), Braille chess (82.8%) and talking watch (98%). Among the students with <6/18 to 1/60 vision, the awareness of visual based technology ranged from 0.8% (typoscope) to 43.6% (video magnifiers). Braille technology was used for reading by 96.4% (books) and for writing by 96.8% (Braille slate and stylus) irrespective of visual status. Other devices were poorly used ranging from nil (typoscope) to 55% (screen readers). The use of math and science learning devices was poor (<20%). Walking canes were used by 59% of students whereas 87.2% students used audible ball for games.Conclusion: The results showed that majority of students used tactile based technology irrespective of visual status.Implications for rehabilitationStudents with visual disability need assistive technology for a wide range of activities including academic learning.Students in schools for the blind who have binocular best corrected vision acuity of 1/60 or better should be encouraged to use visual based assistive technology instead of tactile based.Students with binocular best corrected vision acuity less than1/60 should be encouraged to use other available tactile and sound-based assistive technologies as well as Braille books and Braille slate and stylus for their academic activities including maths and sciences.Teachers should be trained in the use of various assistive technologies for reading, writing, maths, sciences, sports, mobility and activities of daily living.

The key informant strategy to determine the prevalence and causes of functional low vision among children in South India

PURPOSE

To report the prevalence and causes of functional low vision (FLV) in school-age children in Coimbatore District, Tamil Nadu, India and to report our experience using the key informant (KI) method in this setting.

METHODS

Children suspected of having low vision were identified by KIs or Aravind Eye Hospital personnel in Coimbatore District. All identified children underwent a cycloplegic refraction and full eye exam. A primary cause of decreased vision was determined for each child. The prevalence of FLV was calculated for children 6-14 years old. Spectacles and low vision devices were provided free of charge.

RESULTS

345 children aged 6-14 years were referred and 231 had FLV. The positive-predictive value of KI referrals was 64.5%. The prevalence of FLV was 0.071% (7.1 per 10,000; 95% CI 0.062-0.080%) and ranged from 0.026% to 0.141% across the district's blocks. Older children (age 11-14 years; OR 1.41; 95% CI 1.09-1.82) and males (OR 1.52; 95% CI 1.16-1.98) had greater odds of being diagnosed with FLV. The most common causes of FLV were retinal disorders (30.0%) and amblyopia (25.5%). Low vision devices were provided to 169 children who had a mean near and distance visual acuity improvement of 0.31 and 0.63 logMAR, respectively (p < 0.001).

CONCLUSIONS

This study reports a moderate prevalence of FLV and demonstrates the ability of KIs to identify school-age children with FLV in South India. The provision of basic low vision services can improve visual outcomes in this population.

Comparative study of visual dysfunctions in 6-10-year-old very preterm- and full-term-born children

PURPOSE

To compare visual dysfunction between very preterm-born (VPB) children with no retinopathy of prematurity (no-ROP) at 6-10 years of age and age- and sex-matched full-term-born controls.

METHODS

This is an observational, prospective study that included 30 children, 6-10 years of age, born ≤ 32 weeks of gestation, with no-ROP, and 30 age- and sex-matched full-term-born controls, conducted from January 2015 until August 2015. All children underwent complete ophthalmic evaluation. Main outcome measures include visual functions (best corrected visual acuity (BCVA), color vision, and stereoacuity), ocular alignment, refractive errors, and the presence of amblyopia and nystagmus.

RESULTS

Mean BCVA of the right eyes was 0.04 ± 0.08 logMAR for VPB children and 0.02 ± 0.05 logMAR for the full-term children (P = 0.075). Mean BCVA for the left eyes was 0.07 ± 0.09 logMAR for VPB children and 0.02 ± 0.05 logMAR for the full-term children (P = 0.014). Refractive errors were slightly higher though not statistically significant in VPB children compared to full-term children (P = 0.125). The incidence of myopia and hypermetropia was 16.7 and 40%, respectively, in VPB children and 10 and 23.3%, respectively, in full-term children. Anisometropia found only in VPB children with an incidence of 16.7%. Amblyopia found in 10% of VPB children compared to 3.3% in full-term children. Strabismus was found equally in 10% of each group.

CONCLUSION

VPB children with no-ROP are at an increased risk of developing decreased BCVA at least in one eye and anisometropia compared to age-matched full-term controls.

Vision-specific and psychosocial impacts of low vision among patients with low vision at the eastern regional Low Vision Centre

Purpose: To determine vision-specific and psychosocial implications of low vision among patients with low vision visiting the Low Vision Centre of the Eastern Regional Hospital in Ghana.Methodology: This was a descriptive case-control study of 41 patients with low vision and 41 patients with normal vision recruited from the Low Vision Centre of the Eastern Regional Hospital by simple random sampling. Data on vision-specific and psychosocial impacts of low vision was collected using the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25). Biographical and clinical characteristics such as age, gender, educational status, marital status, employment and income status were gathered from consenting patients. Mann–Whitney U analysis using Statistical Package for Social Scientists (SPSS) was conducted to compare scores on vision-specific and psychosocial subscales of the NEI VFQ-25 between patients with low vision and patients with normal vision.Results: Patients with low vision recorded the lowest score on the driving subscale (median = 8.33, IQR [interquartile range]: 8.33–41.67, n = 41, p < 0.001), as well as on distance activities (median = 35.42, IQR = 16.70–58.80). Psychosocial implications of low vision included high dependency (median = 33.33, IQR = 25.00–50.00), reduced mental health (median = 37.50, IQR = 25.00–50.00) and limitation in partaking in social activities (median = 50.00, IQR = 37.50–78.00).Conclusion: Low vision has both vision-specific and psychosocial implications for the patients. Low vision management and services should therefore be tailored to meet these psychosocial and vision-specific needs to enable patients better accept their visual changes and to be better prepared to use their remaining vision to achieve their daily goals.

Are children with low vision adapted to the visual environment in classrooms of mainstream schools?

Purpose:

The study aimed to evaluate the classroom environment of children with low vision and provide recommendations to reduce visual stress, with focus on mainstream schooling.

Methods:

The medical records of 110 children (5–17 years) seen in low vision clinic during 1 year period (2015) at a tertiary care center in south India were extracted. The visual function levels of children were compared to the details of their classroom environment. The study evaluated and recommended the chalkboard visual task size and viewing distance required for children with mild, moderate, and severe visual impairment (VI).

Results:

The major causes of low vision based on the site of abnormality and etiology were retinal (80%) and hereditary (67%) conditions, respectively, in children with mild (n = 18), moderate (n = 72), and severe (n = 20) VI. Many of the children (72%) had difficulty in viewing chalkboard and common strategies used for better visibility included copying from friends (47%) and going closer to chalkboard (42%). To view the chalkboard with reduced visual stress, a child with mild VI can be seated at a maximum distance of 4.3 m from the chalkboard, with the minimum size of visual task (height of lowercase letter writing on chalkboard) recommended to be 3 cm. For 3/60–6/60 range, the maximum viewing distance with the visual task size of 4 cm is recommended to be 85 cm to 1.7 m.

Conclusion:

Simple modifications of the visual task size and seating arrangements can aid children with low vision with better visibility of chalkboard and reduced visual stress to manage in mainstream schools.

Need for optical intervention in children attending a school for the blind in Eritrea

PURPOSE

To identify the need for optical intervention including spectacles and low vision devices (LVDs) in children attending the only school for the blind in Eritrea.

METHODS

A total of 92 children were examined using the World Health Organization Prevention of Blindness program form for the recording of children with blindness and vision impairment. Examination included distance and near visual acuity (VA), refraction, trial of LVDs and evaluation of anterior and posterior segments. All the children who showed at least one line improvement in distance or near VA with refractive correction and/or LVDs were provided with these devices.

RESULTS

Six children had distance VA of ≥6/18 (no vision impairment, NVI) at presentation and were excluded from analysis. For the remaining 86 children, male to female ratio was 1.2:1.0 with a mean age of 11.8 ± 2.8 years (range: 6-17 years). At presentation, 47 (54.7 per cent) children were blind (VA <3/60) and 24 (27.9 per cent) were severely visually impaired (VA <6/60-3/60), which reduced to 42 (48.9 per cent) and seven (8.1 per cent) children after refraction, respectively. A further 5.8 per cent (five children) achieved NVI with refractive correction. Using distance LVDs, 26 (30.2 per cent) and 16 (18.6 per cent) children had NVI and moderate vision impairment (VA <6/18-6/60), respectively. In terms of near vision, eight (9.3 per cent) children had near VA better than 1.00 M at presentation, which improved to 11 (12.8 per cent) with refractive correction and 19 (22.1 per cent) with near LVDs. A total of 29 spectacles and 42 LVDs were provided.

CONCLUSION

A significant number of children at the school for the blind benefited from refractive correction and LVDs. With such optical intervention, many of these children could study at mainstream schools with print media. A system including comprehensive vision examinations before admission to the school, refractive services and low vision rehabilitation is required to ensure that children with adequate residual vision do not have to be limited to learning in Braille media.

Tablet computers versus optical aids to support education and learning in children and young people with low vision: protocol for a pilot randomised controlled trial, CREATE (Children Reading with Electronic Assistance To Educate)

INTRODUCTION

Low vision and blindness adversely affect education and independence of children and young people. New 'assistive' technologies such as tablet computers can display text in enlarged font, read text out to the user, allow speech input and conversion into typed text, offer document and spreadsheet processing and give access to wide sources of information such as the internet. Research on these devices in low vision has been limited to case series.

METHODS AND ANALYSIS

We will carry out a pilot randomised controlled trial (RCT) to assess the feasibility of a full RCT of assistive technologies for children/young people with low vision. We will recruit 40 students age 10-18 years in India and the UK, whom we will randomise 1:1 into two parallel groups. The active intervention will be Apple iPads; the control arm will be the local standard low-vision aid care. Primary outcomes will be acceptance/usage, accessibility of the device and trial feasibility measures (time to recruit children, lost to follow-up). Exploratory outcomes will be validated measures of vision-related quality of life for children/young people as well as validated measures of reading and educational outcomes. In addition, we will carry out semistructured interviews with the participants and their teachers.

ETHICS AND DISSEMINATION

NRES reference 15/NS/0068; dissemination is planned via healthcare and education sector conferences and publications, as well as via patient support organisations.

TRIAL REGISTRATION NUMBER

NCT02798848; IRAS ID 179658, UCL reference 15/0570.

Childhood amblyopia: current management and new trends

INTRODUCTION OR BACKGROUND

With a prevalence of 2-5%, amblyopia is the most common vision deficit in children in the UK and the second most common cause of functional low vision in children in low-income countries.

SOURCES OF DATA

Pubmed, Cochrane library and clinical trial registries (clinicaltrials.gov, ISRCTN, UKCRN portfolio database).

AREAS OF AGREEMENT

Screening and treatment at the age of 4-5 years are cost efficient and clinically effective. Optical treatment (glasses) alone can improve visual acuity, with residual amblyopia treated by part-time occlusion or pharmacological blurring of the better-seeing eye. Treatment after the end of the conventional 'critical period' can improve vision, but in strabismic amblyopia carries a low risk of double vision.

AREAS OF CONTROVERSY

It is not clear whether earlier vision screening would be cost efficient and associated with better outcomes. Optimization of treatment by individualized patching regimes or early start of occlusion, and novel binocular treatment approaches may enhance adherence to treatment, provide better outcomes and shorten treatment duration.

GROWING POINTS

Binocular treatments for amblyopia.

AREAS TIMELY FOR DEVELOPING RESEARCH

Impact of amblyopia on education and quality of life; optimal screening timing and tests; optimal administration of conventional treatments; development of child-friendly, effective and safe binocular treatments.

Vision screening in children: a retrospective study of social and demographic factors with regards to visual outcomes

Background

Amblyopia and its risk factors have been demonstrated to be more common among children from low socioeconomic backgrounds. We sought to investigate this association in a region with orthoptic-delivered screening and whole population coverage, and to also examine the association of the Health Plan Indicator (HPI) with screening outcome.

Methods

Screening examination outcomes, postcodes and HPIs were extracted from the community child health database for every child who underwent preschool vision screening between March 2010 and February 2011 Tayside. We obtained the Scottish Index of Multiple Deprivation score for every child as a measure of area-based deprivation. We assessed the vulnerability/needs of the individual family through the HPI—‘Core’ (children and families receiving universal health visiting service), ‘Additional’ (receiving additional health/social support) and ‘Intensive’ (receiving high levels of support). The outcomes from follow-up examinations for those who failed screening were extracted from the orthoptic department database.

Results

4365 children were screened during the year 2010–2011 of whom 523 (11.9%) failed. The odds of children from the least deprived socioeconomic group passing the visual screening test was 1.4 times higher than those from the most deprived socioeconomic group (OR 1.4, 95% CI 1.07 to 1.89, p=0.01). The odds of a child from a family assigned as ‘Intensive’ failing the preschool visual screening test was three times greater than the odds of a child from a family assigned as ‘Core’ (OR 3.59, 95% CI 1.6 to 7.8, p=0.001).

Conclusions

We found that children from the most deprived backgrounds and those from unstable homes were more likely to fail preschool vision screening.

Binocular versus standard occlusion or blurring treatment for unilateral amblyopia in children aged three to eight years

BACKGROUND

Current treatments for amblyopia in children, occlusion and pharmacological blurring, have had limited success, with less than two-thirds of children achieving good visual acuity of at least 0.20 logMAR in the amblyopic eye, limited improvement of stereopsis, and poor compliance. A new treatment approach, based on the dichoptic presentation of movies or computer games (images presented separately to each eye), may yield better results, as it aims to balance the input of visual information from each eye to the brain. Compliance may also improve with these more child-friendly treatment procedures.

OBJECTIVES

To determine whether binocular treatments in children aged three to eight years with unilateral amblyopia result in better visual outcomes than conventional occlusion or pharmacological blurring treatment.

SEARCH METHODS

We searched the Cochrane Eyes and Vision Group Trials Register (last date of searches: 14 April 2015), the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 3), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to April 2015), EMBASE (January 1980 to April 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials.

SELECTION CRITERIA

Two review authors independently screened the results of the search in order to identify studies that met the inclusion criteria of the review: randomised controlled trials (RCTs) that enrolled participants between the ages of three and eight years old with unilateral amblyopia, defined as best-corrected visual acuity (BCVA) worse than 0.200 logMAR in the amblyopic eye, and BCVA 0.200 logMAR or better in the fellow eye, in the presence of an amblyogenic risk factor such as anisometropia, strabismus, or both. Prior to enrolment, participants were to have undergone a cycloplegic refraction and comprehensive ophthalmic examination including fundal examination. In addition, participants had to have completed a period of optical treatment, if indicated, and BCVA in the amblyopic eye had to remain unchanged on two consecutive assessments despite reportedly good compliance with glasses wearing. Participants were not to have received any treatment other than optical treatment prior to enrolment. We planned to include any type of binocular viewing intervention; these could be delivered on different devices including computer monitors viewed with LCD shutter glasses or hand-held screens including mobile phone screens with lenticular prism overlay. Control groups were to have received standard amblyopia treatment; this could include occlusion or pharmacological blurring of the better-seeing eye. We planned to include full-time (all waking hours) and part-time (between 1 and 12 hours a day) occlusion regimens.

DATA COLLECTION AND ANALYSIS

We planned to use standard methodological procedures expected by The Cochrane Collaboration. We had planned to meta-analyse the primary outcome, that is mean distance BCVA in the amblyopic eye at 12 months after the cessation of treatment.

MAIN RESULTS

We could identify no RCTs in this subject area.

AUTHORS' CONCLUSIONS

Further research is required to allow decisions about implementation of binocular treatments for amblyopia in clinical practice. Currently there are no clinical trials offering standardised evidence of the safety and effectiveness of binocular treatments, but results from non-controlled cohort studies are encouraging. Future research should be conducted in the form of RCTs, using acknowledged methods of visual acuity and stereoacuity assessment with known reproducibility. Other important outcome measures include outcomes reported by users, compliance with treatment, and recurrence of amblyopia after cessation of treatment.

Assistive technology for children and young people with low vision

BACKGROUND

Recent technological developments, such as the near universal spread of mobile phones and portable computers and improvements in the accessibility features of these devices, give children and young people with low vision greater independent access to information. Some electronic technologies, such as closed circuit TV, are well established low vision aids and newer versions, such as electronic readers or off-the shelf tablet computers, may offer similar functionalities with easier portability and at lower cost.

OBJECTIVES

To assess the effect of electronic assistive technologies on reading, educational outcomes and quality of life in children and young people with low vision.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 9), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to October 2014), EMBASE (January 1980 to October 2014), the Health Technology Assessment Programme (HTA) (www.hta.ac.uk/), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 30 October 2014.

SELECTION CRITERIA

We intended to include randomised controlled trials (RCTs) and quasi-RCTs in this review. We planned to include trials involving children between the ages of 5 and 16 years with low vision as defined by, or equivalent to, the WHO 1992 definition of low vision. We planned to include studies that explore the use of assistive technologies (ATs). These could include all types of closed circuit television/electronic vision enhancement systems (CCTV/EVES), computer technology including tablet computers and adaptive technologies such as screen readers, screen magnification and optical character recognition (OCR). We intended to compare the use of ATs with standard optical aids, which include distance refractive correction (with appropriate near addition for aphakic (no lens)/pseudophakic (with lens implant) patients) and monocular/binoculars for distance and brightfield magnifiers for near. We also planned to include studies that compare different types of ATs with each other, without or in addition to conventional optical aids, and those that compare ATs given with or without instructions for use.

DATA COLLECTION AND ANALYSIS

Independently, two review authors reviewed titles and abstracts for eligibility. They divided studies into categories to 'definitely include', 'definitely exclude' and 'possibly include', and the same two authors made final judgements about inclusion/exclusion by obtaining full-text copies of the studies in the 'possibly include' category.

MAIN RESULTS

We did not identify any randomised controlled trials in this subject area.

AUTHORS' CONCLUSIONS

High-quality evidence about the usefulness of electronic AT for children and young people with visual impairment is needed to inform the choice healthcare and education providers and family have to make when selecting a technology. Randomised controlled trials are needed to assess the impact of AT. Research protocols should carefully select outcomes relevant not only to the scientific community, but more importantly to families and teachers. Functional outcomes such as reading accuracy, comprehension and speed should be recorded, as well as the impact of AT on independent learning and quality of life.

Prescribed computer games in addition to occlusion versus standard occlusion treatment for childhood amblyopia: a pilot randomised controlled trial

BACKGROUND

Amblyopia ("lazy eye") is the commonest vision deficit in children. If not fully corrected by glasses, amblyopia is treated by patching or blurring the better-seeing eye. Compliance with patching is often poor. Computer-based activities are increasingly topical, both as an adjunct to standard treatment and as a platform for novel treatments. Acceptability by families has not been explored, and feasibility of a randomised controlled trial (RCT) using computer games in terms of recruitment and treatment acceptability is uncertain.

METHODS

We carried out a pilot RCT to test whether computer-based activities are acceptable and accessible to families and to test trial methods such as recruitment and retention rates, randomisation, trial-specific data collection tools and analysis. The trial had three arms: standard near activity advice, Eye Five, a package developed for children with amblyopia, and an off-the-shelf handheld games console with pre-installed games. We enrolled 60 children age 3-8 years with moderate or severe amblyopia after completion of optical treatment.

RESULTS

This trial was registered as UKCRN-ID 11074. Pre-screening of 3600 medical notes identified 189 potentially eligible children, of whom 60 remained eligible after optical treatment, and were enrolled between April 2012 and March 2013. One participant was randomised twice and withdrawn from the study. Of the 58 remaining, 37 were boys. The mean (SD) age was 4.6 (1.7) years. Thirty-seven had moderate and 21 severe amblyopia. Three participants were withdrawn at week 6, and in total, four were lost to follow-up at week 12. Most children and parents/carers found the study procedures, i.e. occlusion treatment, usage of the allocated near activity and completion of a study diary, easy. The prescribed cumulative dose of near activity was 84 h at 12 weeks. Reported near activity usage numbers were close to prescribed numbers in moderate amblyopes (94 % of prescribed) but markedly less in severe amblyopes (64 %). Reported occlusion usage at 12 weeks was 90 % of prescribed dose for moderate and 33 % for severe amblyopes.

CONCLUSIONS

Computer-based games and activities appear acceptable to families as part of their child's amblyopia treatment. Trial methods were appropriate and accepted by families.

Optical reading aids for children and young people with low vision

BACKGROUND

Low vision in childhood is a significant barrier to learning and development, particularly for reading and education. Optical low vision aids may be used to maximise the child's functional vision. The World Health Organization (WHO) has previously highlighted the importance of the use of low vision aids in managing children with visual impairment across the world.

OBJECTIVES

To assess the effect of optical low vision aids on reading in children and young people with low vision.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 12), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to January 2015), EMBASE (January 1980 to January 2015), the Health Technology Assessment Programme (HTA) (www.hta.ac.uk/), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 8 January 2015.We also used manual searching to check the references listed in retrieved articles. Manufacturers of low vision aids were contacted to request any information about studies or research regarding their products.

SELECTION CRITERIA

We planned to include randomised controlled trials (RCTs) and quasi-RCTs where any optical low vision aid was compared to standard refractive correction in children and young people aged between 5 and 16 years of age with low vision as defined by the WHO. We planned to include within-person design studies where the order of presentation of devices was randomised.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed the search results for eligibility .

MAIN RESULTS

No studies met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

There is a lack of good quality evidence regarding the use of optical low vision aids in children and young people. As such, no implications for practice can be drawn. We believe future research should include functional outcome measures such as reading speed, accuracy and comprehension, as well as the effect of low vision aids on quality of life, in order to truly assess and compare the effect of these devices on a child's life and development.

A lack of vision: evidence for poor communication of visual problems and support needs in education statements/plans for children with SEN

OBJECTIVE

Visual dysfunction is more common in children with neurological impairments and previous studies have recommended such children receive visual and refractive assessment. In the UK, children with neurological impairment often have educational statementing for Special Educational Needs (SEN) and the statement should detail all health care and support needs to ensure the child's needs are met during school life.

STUDY DESIGN

This study examined the representation of visual information in statements of SEN and compared this to orthoptic visual information from school visual assessments for children in a special school in Northern Ireland, UK.

METHODS

The parents of 115 school children in a special school were informed about the study via written information. Participation involved parents permitting the researchers to access their child's SEN educational statement and orthoptic clinical records.

RESULTS

Statement information was accessed for 28 participants aged between four and 19 years; 25 contained visual information. Two participants were identified in their statements as having a certification of visual impairment. An additional 10 children had visual acuity ≥ 0.3 logMAR. This visual deficit was not reported in statements in eight out of these 12 cases (67%). 11 participants had significant refractive error and wore spectacles, but only five (45%) had this requirement recorded in their statement. Overall, 10 participants (55%) had either reduced visual acuity or significant refractive error which was not recorded in their statement.

CONCLUSIONS

Despite additional visual needs being common, and described in clinical records, the majority of those with reduced vision and/or spectacle requirements did not have this information included in their statement. If visual limitations are not recognized by educational services, the child's needs may not be met during school life. More comprehensive eye care services, embedded with stakeholder communication and links to education are necessary to improve understanding of vision for children with neurological impairments.

The status of childhood blindness and functional low vision in the Eastern Mediterranean region in 2012

Childhood blindness and visual impairment (CBVI) are major disabilities that compromise the normal development of children. Health resources and practices to prevent CBVI are suboptimal in most countries in the Eastern Mediterranean Region (EMR). We reviewed the magnitude and the etiologies of childhood visual disabilities based on the estimates using socioeconomic proxy indicators such as gross domestic product (GDP) per capita and <5-year mortality rates. The result of these findings will facilitate novel concepts in addressing and developing services to effectively reduce CBVI in this region. The current study determined the rates of bilateral blindness (defined as  Best corrected visual acuity(BCVA)) less than 3/60 in the better eye or a visual field of 10° surrounding central fixation) and functional low vision (FLV) (visual impairment for which no treatment or refractive correction can improve the vision up to >6/18 in a better eye) in children <15 years old. We used the 2011 population projections, <5-year mortality rates and GDP per capita of 23 countries (collectively grouped as EMR). Based on the GDP, we divided the countries into three groups; high, middle- and low-income nations. By applying the bilateral blindness and FLV rates to high, middle- and low-income countries from the global literature to the population of children <15 years, we estimated that there could be 238,500 children with bilateral blindness (rate 1.2/1,000) in the region. In addition, there could be approximately 417,725 children with FLV (rate of 2.1/1,000) in the region. The causes of visual disability in the three groups are also discussed based on the available data. As our estimates are based on hospital and blind school studies in the past, they could have serious limitations for projecting the present magnitude and causes of visual disabilities in children of EMR. An effective approach to eye health care and screening for children within primary health care and with the available resources are discussed. The objectives, strategies, and operating procedures for child eye-care are presented. Variables impacting proper screening are discussed. To reach the targets, we recommend urgent implementation of new approaches to low vision and rehabilitation of children.

Amblyopia screening in Bulgaria

PURPOSE

To determine the prevalence of amblyopia and the average age at first ophthalmological examination of school-aged children from northwestern Bulgaria.

METHODS

Visual acuity testing, stereopsis, orthoptics, ocular motility, non-cycloplegic refraction, direct ophthalmoscopy, and external ocular inspection were performed. Cycloplegic refraction and indirect ophthalmoscopy were done as necessary. A total of 2,054 children (1,020 girls and 1,034 boys) were divided into three age groups: 6 to 8 years (803 children), 8 to 10 years (719 children), and 10 to 12 years (530 children).

RESULTS

A total of 1,861 children (90.6%) received their first examination: 754 (93.9%) aged 6 to 8 years, 638 (88.7%) aged 8 to 10 years, and 469 (88.2%) aged 10 to 12 years. Amblyopia was detected in 88 children (4.3%): 42 (5.2%) aged 6 to 8 years, 27 (3.8%) aged 8 to 10 years, and 19 (3.6%) aged 10 to 12 years. The first group had higher prevalence compared to countries with well-developed screening programs. Refractive errors were detected in 403 children (19.7%): 125 (15.6%) aged 6 to 8 years, 146 (20.3%) aged 8 to 10 years, and 132 (24.8%) aged 10 to 12 years. The estimated prevalence increases with age. Strabismus was detected in 24 children (1.2%): 8 (1.0%) aged 6 to 8 years, 7 (1.0%) aged 8 to 10 years, and 9 (1.7%) aged 10 to 12 years.

CONCLUSIONS

The lack of screening programs in Bulgaria is the main reason for late diagnosis of amblyopia. The "Do Good "project provided eye examination of school-aged children aged 6 to 12 years, when amblyopia is curable. This model could be used in establishing a Bulgarian national screening program.

The relationship between anisometropia and amblyopia

This review aims to disentangle cause and effect in the relationship between anisometropia and amblyopia. Specifically, we examine the literature for evidence to support different possible developmental sequences that could ultimately lead to the presentation of both conditions. The prevalence of anisometropia is around 20% for an inter-ocular difference of 0.5D or greater in spherical equivalent refraction, falling to 2-3%, for an inter-ocular difference of 3D or above. Anisometropia prevalence is relatively high in the weeks following birth, in the teenage years coinciding with the onset of myopia and, most notably, in older adults starting after the onset of presbyopia. It has about one-third the prevalence of bilateral refractive errors of the same magnitude. Importantly, the prevalence of anisometropia is higher in highly ametropic groups, suggesting that emmetropization failures underlying ametropia and anisometropia may be similar. Amblyopia is present in 1-3% of humans and around one-half to two-thirds of amblyopes have anisometropia either alone or in combination with strabismus. The frequent co-existence of amblyopia and anisometropia at a child's first clinical examination promotes the belief that the anisometropia has caused the amblyopia, as has been demonstrated in animal models of the condition. In reviewing the human and monkey literature however it is clear that there are additional paths beyond this classic hypothesis to the co-occurrence of anisometropia and amblyopia. For example, after the emergence of amblyopia secondary to either deprivation or strabismus, anisometropia often follows. In cases of anisometropia with no apparent deprivation or strabismus, questions remain about the failure of the emmetropization mechanism that routinely eliminates infantile anisometropia. Also, the chronology of amblyopia development is poorly documented in cases of 'pure' anisometropic amblyopia. Although indirect, the therapeutic impact of refractive correction on anisometropic amblyopia provides strong support for the hypothesis that the anisometropia caused the amblyopia. Direct evidence for the aetiology of anisometropic amblyopia will require longitudinal tracking of at-risk infants, which poses numerous methodological and ethical challenges. However, if we are to prevent this condition, we must understand the factors that cause it to develop.

Profile of patients presenting at a low vision clinic in a developing country

Background

Low vision is an important public health problem; however, very few low vision clinics are available to address the needs of low vision patients in most developing countries. The purpose of this study was to describe the characteristics of patients attending the low vision clinic of a Nigerian tertiary hospital.

Methods

This was a prospective cross sectional study of all new patients seen at the low vision clinic over a 36 month period. Patients were administered with a structured questionnaire, and were examined and tested with low vision devices by the attending low vision specialist. Information on the demographic and clinical characteristics of the patients was recorded.

Results

A total of 193 new patients seen during the period were studied. The mean age was 41.4 years, and their ages ranged between 6 and 90 years with a male to female ratio of 1.9:1. Majority (58%) were aged below 50 years, 23.3% were children (≤15 years), while 21.8% were elderly patients (≥65 years). The commonest cause of low vision was retinitis pigmentosa (16.6%); 14.5% had age related macular degeneration (ARMD); 9.8% had albinism; while only 1% had diabetic retinopathy. ARMD (45.2%) was the commonest cause in the elderly patients, while albinism (24.4%) and optic atrophy (24.4%) were the commonest in children.

Conclusion

The demographic and clinical characteristics of low vision patients seen in this clinic are similar to that of patients in other developing countries, but different from those in developed countries. Elderly patients and females may be under-utilising low vision services. There is a need for further research into the determinants of low vision service utilisation in developing countries. This would further aid the planning and delivery of services to low vision patients in these countries.