Risk factors for amblyopia in the vision in preschoolers study

Feasibility of a school-based vision screening program to detect undiagnosed visual problems in kindergarten children in Ontario

BACKGROUND

Visual problems can negatively affect visual development and learning but often go undetected. We assessed the feasibility of scaling up a school-based screening program to identify and treat kindergarten children with visual problems.

METHODS

We conducted a prospective cohort study offering vision screening to junior (JK) and senior kindergarten (SK) children attending 43 schools in 15 Ontario communities. Screening comprised photoscreeners and tests of visual acuity, stereoacuity and eye alignment. Children who failed any test were referred for a comprehensive eye examination, with treatment as needed (e.g., glasses).

RESULTS

Using a passive consent model, 89% of children were screened compared with 62% using an active consent model (p < 0.001). Referral rates to an optometrist varied across schools (mean referral rate for children in JK 53%, range 25%-83%; mean referral rate for children in SK 34%, range 12%-61%). Among 4811 children who were screened, a visual problem was detected in 516 (10.7%), including 164 (3.4%) with amblyopia and 324 (6.7%) with clinically significant refractive errors. For 347 (67.2%) of the children with a visual problem, this was their first eye examination. Rescreening in Year 2 did not lead to detection of additional problems among children who passed screening in Year 1. Regardless of location (child's school or optometrist's office), 1563 (68.9%) of children attended the follow-up optometry examination. Most of the children who were surveyed (291 of 322, 90.4%) indicated that they enjoyed vision screening.

INTERPRETATION

Many children in Ontario with a visual problem were not being identified by the status quo in 2015-2017. We found that in-school vision screening with follow-up eye examinations is an effective strategy for identifying at-risk children and placing them in eye care before grade 1.

Influence of prenatal environment and birth parameters on amblyopia, strabismus, and anisometropia

PURPOSE

To report the prevalence of amblyopia, strabismus, and anisometropia in a young adult population at a single center in Australia and to investigate the underlying prenatal and early-life risk factors.

METHODS

Participants in the Raine Study have been followed from mid-gestation (n = 2,868 newborns) to young adulthood. At age 20 years, 1,344 participants had a comprehensive eye examination, including visual acuity and a detailed orthoptic assessment. Risk factors were determined from medical records and questionnaires completed by the mothers at 18 weeks' gestation. The main outcome measures were the proportions of participants with amblyopia, esotropia, exotropia, or anisometropia (defined as >1 D difference).

RESULTS

Of the 1,125 white participants, 12 (1.1%) had amblyopia, 39 (3.5%) had strabismus, and 33 (2.9%) had anisometropia. In multivariable logistic regression, amblyopia was associated with a maternal history of pregnancy-induced hypertension (OR = 3.80; 95% CI, 1.19-12.13); esotropia, with lower gestational age (OR = 0.97; 95% CI, 0.95-0.97) and a heavier placenta (OR = 1.02; 95% CI, 1.00-1.04); exotropia, with a maternal history of previously treated hypertension (OR = 4.00; 95% CI, 1.06-15.03) and maternal use of recreational drugs during early pregnancy (OR = 3.61; 95% CI, 1.06-15.03); and anisometropia, with older maternal age (OR = 1.07; 95% CI, 1.01-1.14) and an abnormal umbilical cord (OR = 2.39; 95% CI, 1.04-5.47).

CONCLUSIONS

The prevalence of amblyopia, strabismus, and anisometropia in this cohort was similar to that in other studies. Preterm birth and maternal health may have adverse effects on eye development.

Effect of Primary Occlusion Therapy in Asymmetric, Bilateral Amblyopia

PURPOSE

Many bilateral amblyopia patients have asymmetric visual acuity (VA). There is no standard treatment for these patients, and outcomes have not been well described. Our goal is to compare VA outcomes in this group based on timing of occlusion therapy.

DESIGN

Retrospective interventional comparative case series.

METHODS

Setting: Institutional practice. PatientPopulation: Patients diagnosed with amblyopia at Boston Children's Hospital between 2010 and 2014. InclusionCriteria: VA ≥ 0.3 logMAR bilaterally by objective optotype-based measures, interocular difference (IOD) ≥ 0.18 logMAR, age 2-12 years. ExclusionCriteria: Loss to follow-up, managed surgically, deprivation amblyopia. Patients had either primary or secondary occlusion (primary = initiated when VA ≥ 0.3 logMAR bilaterally; secondary = initiated to correct residual IOD once VA improved to ≤0.18 logMAR in the stronger eye). ObservationProcedure: Patient demographics, VA, IOD, and stereopsis were compared between groups. OutcomeMeasures: VA improvement at 12-18 months and at last visits.

RESULTS

Of 2,200 patients reviewed, 167 (7.6%) had asymmetric, bilateral amblyopia; 98 met inclusion and exclusion criteria. Patients were equally divided between primary (n = 50) and secondary (n = 48) occlusion groups. There were no differences in demographics, baseline VA, or IOD between groups (P ≥ .22), although the primary occlusion group had a higher proportion of strabismic amblyopia (P = .007). VA in both eyes, IOD, and stereopsis improved similarly between groups, even after stratifying by amblyopia subtype (P ≥ .48). The secondary occlusion group was more likely to achieve 20/30 bilaterally and IOD ≤ 1 line at 12-18 months (P ≤ .4), although this equalized by the last visit.

CONCLUSION

In patients with asymmetric, bilateral amblyopia, VA improved by 4 lines in the weaker eye and 2 lines in the stronger eye, while IOD improved by 2 lines, irrespective of occlusion status. Primary occlusion thus provided no further benefit over spectacle correction alone.

Accuracy of noncycloplegic photorefraction using Spot photoscreener in detecting amblyopia risk factors in preschool children in an Indian eye clinic

Purpose:

To evaluate the accuracy of Spot photoscreener (PS) as a noncycloplegic photorefractor in detecting amblyopia risk factors (ARFs) in preschool children in an Indian eye clinic setting. Also, to derive appropriate cutoff values for screening to obtain maximum sensitivity and specificity of the device in detecting ARF.

Methods:

This was a cross-sectional study conducted in the outpatient pediatric eye clinic at a tertiary eye care institute. A Spot PS was used to screen all the children between the ages of 6 months and 5 years that presented to the eye clinic from August 2018 to October 2018. This screening was followed by a complete eye examination, including cycloplegic refraction by a masked examiner. The 2013 American Association for Pediatric Ophthalmology and Strabismus (AAPOS) guidelines were considered the standard cutoff values for clinically significant refractive error in children younger than 5 years of age.

Results:

The study comprised of 219 children. The Spot PS diagnosed 135 (61.64%) children with ARF as compared with 124 (56.62%) children detected by clinic examination. For ARF detection, the Spot photoscreeneer had 85.48% sensitivity, 69.47% specificity, 78.52% positive predictive value and 78.57% negative predictive value. The sensitivity for detection of strabismus and hypermetropia was very low (42% and 36%, respectively). The 95% limits of agreement ranged from −5.48 to +5.59 diopters (D) with a bias of 0.06 D for spherical equivalent between noncycloplegic photorefraction and cycloplegic refraction.

Conclusion:

The Spot PS may be used as a screening tool to detect ARF in children younger than 5 years of age keeping its limitations in consideration. However, the performance can be improved by modifying the cutoff values for the referral.

Objective Assessment of the Effect of Optical Treatment on Magnocellular and Parvocellular-biased Visual Response in Anisometropic Amblyopia

Purpose

Optical treatment can improve visual function in anisometropic amblyopia, but there is no electrophysiological evidence, and the underlying change in visual pathway remains unknown. Our aims were to characterize the functional loss in magnocellular and parvocellular visual pathways in anisometropic amblyopia at baseline and to investigate the effect of optical treatment on the 2 visual pathways.

Methods

Using isolated-check visual-evoked potential, we measured the magnocellular- and parvocellular-biased contrast response functions in 15 normal controls (20.13 ± 3.93 years; mean ± standard deviation), 16 patients with anisometropic amblyopia (18.00 ± 6.04 years) who were fully refractive corrected before and 29 (19.41 ± 7.41 years) who had never been corrected. Twelve previously uncorrected amblyopes received optical treatment for more than 2 months and finished the follow-up measurement.

Results

Both the magnocellular- and parvocellular-biased contrast response functions in the amblyopic eye exhibited significantly reduced response and weaker contrast gains. We also found that the uncorrected amblyopes showed a more severe response reduction in magnocellular-biased, but not parvocellular-biased condition when compared with those corrected, with a weaker initial contrast gain and lower maximal response. After optical treatment, 12 uncorrected amblyopes demonstrated improved visual acuity of the amblyopic eye and a significant response gain to magnocellular-biased but not parvocellular-biased stimuli.

Conclusions

We demonstrated deficits to both magnocellular- and parvocellular-biased stimuli in subjects with anisometropic amblyopia. Optical treatment could produce neurophysiological changes in visual pathways even in older children and adults, which may be mediated through the magnocellular pathway.

Refractive Errors and Amblyopia Among Children Screened by the UCLA Preschool Vision Program in Los Angeles County

PURPOSE

To summarize the results of 5 years of vision screening with the University of California, Los Angeles (UCLA) Preschool Vision Program (UPVP).

DESIGN

Retrospective evaluation of a screening program.

METHODS

The UPVP performed visual acuity and undilated noncycloplegic refractive screening using an autorefractor on 93,097 children between 2012 and 2017. Of these, 79,451 children, who were between 3 and 5 years old, were screened for the first time, and 14,259 were referred for full cycloplegic examination if they met specific refractive criteria for myopia, hyperopia, astigmatism, or anisometropia. UPVP performed 6779 cycloplegic examinations on this population. Data from the right eye only were included in this analysis.

RESULTS

Of the examined population, hyperopia was found in 61% (4018), myopia in 20% (1336), and astigmatism in 93% (6122) of children. Latino children had higher rates of astigmatism and worse visual acuity compared to all other races/ethnicities. An astigmatism cutoff of ≥1.50 diopters (D) in either eye correctly predicted the need for glasses 93% of the time; increasing this cutoff to ≥1.50 D in both eyes increased the positive predictive value to 96%. Refractive amblyopia was found in 780 children (1.0% of the screened population and 11.5% of the examined population), and of these, 211 (27%) were bilaterally amblyopic.

CONCLUSIONS

These data represent the largest published sample of vision screening results on preschool-aged children, provide additional insight on the proportion of common refractive errors and their association with race/ethnicity, and can inform screening criteria to more accurately identify children who need intervention to prevent permanent vision loss.

The practise of paediatric optometry in a low-resource environment

BACKGROUND

The role of optometrists in paediatric visual assessment must compliment the role of other eye-care practitioners at all levels of care. This study was undertaken to determine if optometrists in Ghana screen, diagnose and manage paediatric ocular conditions (for example, strabismus, amblyopia), and further assessed if optometrists in Ghana have the requisite paediatric instrumentation in their practices.

METHODS

This was a cross-sectional descriptive survey involving optometrists in both public and private eye-care sectors in Ghana. A paediatric visual assessment questionnaire was sent to all registered optometrists in Ghana. The contents of the questionnaire evaluated areas of vision assessment, refraction, and previous diagnosis and management, which were matched with practice characteristics such as location, type of practice and type of employment. Chi-squared statistic was used to test associations between variables.

RESULTS

Responses were obtained from 140 optometrists out of the 326 registered optometrists, representing a response rate of 46 per cent. Overall, less than half of respondents (64 which represents 46 per cent) assessed themselves as practising full-scope paediatric eye care. These self-assessment views were more common among optometrists at the regional level (111: 79.3 per cent), followed by the district (20: 14.3 per cent) and sub-district levels (nine: 6.4 per cent) (χ² = 4.774, p < 0.05), but was not influenced by type of employment, type of practice and level of training (p > 0.05). In addition, the study revealed that many respondents were more likely to assess pre-schoolers' visual acuity (VA) (121: 96.0 per cent), do refraction (109: 88.6 per cent) and perform binocular vision (BV) assessment (93: 76.9 per cent) compared to the toddlers' VA (72: 55.4 per cent), refraction (57: 46 per cent) and BV assessment (68: 56.2 per cent).

CONCLUSION

Full-scope paediatric eye care services among optometrists in Ghana is limited.

Guide de pratique clinique fondé sur des données probantes pour l'examen périodique de la vue chez les enfants de 0 à 5 ans au Canada

CONTEXTE

Étant donné que les maladies oculaires avant l'âge de 5 ans sont courantes, une certaine forme de dépistage des troubles de la vision devrait être effectuée chez les enfants avant qu'ils ne fréquentent l'école primaire. Cependant, l'absence de recommandations nationales cohérentes crée de la confusion chez les patients, les professionnels des soins oculovisuels et les gouvernements. MéTHODES: L'objectif de ce document est de fournir des recommandations quant aux types d'examens oculaires à pratiquer chez les enfants en bonne santé de 0 à 5 ans ainsi que sur le moment et la périodicité de tels examens. Une recension des écrits a produit 403 articles. Un comité d'experts multidisciplinaire (composé de deux optométristes, d'un ophtalmologiste effectuant des examens complets de la vue, d'un ophtalmologiste pratiquant en pédiatrie, d'un médecin de famille et d'un pédiatre) a établi de façon indépendante les articles jugés essentiels à la question clinique. Les articles se prêtant à un classement [n = 16] ont ensuite été soumis à une évaluation critique indépendante par un groupe externe, lequel a fourni un profil « GRADE » des articles à utiliser et leur a attribué une cote.

RECOMMANDATIONS

En plus du dépistage de routine effectué par les professionnels de première ligne, un examen complet de la vue mené par un professionnel possédant l'expertise nécessaire à la détection des facteurs de risque de l'amblyopie (comme un ophtalmologiste ou un optométriste) est requis durant la petite enfance. Les conclusions confirment l'importance de la détection précoce de l'amblyopie avant 36 mois et au plus tard 48 mois par le dépistage assorti d'au moins un examen complet de la vue avant l'âge de 5 ans.

CONCLUSIONS

Le dépistage de la vue effectué chez les bébés et les enfants par les fournisseurs de soins de première ligne au cours des consultations de routine et des vaccinations périodiques est un élément essentiel de la détection des maladies oculaires. Toutefois, le potentiel de détection précoce est limité et un examen oculovisuel complet est également recommandé avant que l'enfant n'entre à l'école. Si l'amblyopie, le strabisme ou une autre pathologie oculaire est détecté ou soupçonné, et que le problème dépasse le champ de compétences du professionnel qui examine le patient, celui-ci peut être dirigé vers le spécialiste approprié, ce qui permet d'amorcer le traitement en temps opportun.

Evidence-based clinical practice guidelines for the periodic eye examination in children aged 0-5 years in Canada

BACKGROUND

As eye disease before age 5 years is common, some form of vision screening should be performed on children before attending primary school. However, the lack of consistent national recommendations creates confusion for patients, eye care professionals, and governments alike.

METHODS

The objective of this document is to provide guidance on the recommended timing, intervals, and types of ocular assessments for healthy children aged 0-5 years. A literature search yielded 403 articles. A multidisciplinary expert committee (comprising 2 optometrists, a comprehensive ophthalmologist, a pediatric ophthalmologist, a family physician, and a pediatrician) independently determined those articles deemed to be key to the clinical question. Articles that were gradable (n = 16) were then submitted for independent critical appraisal by an external review group, which provided a Grading of Recommendations Assessment, Development and Evaluation profile of the reviewed articles to use for assigning a grade of evidence.

RECOMMENDATIONS

In addition to routine screening by a primary health care professional, a comprehensive eye examination by an individual with the expertise to detect risk factors for amblyopia-such as an ophthalmologist or optometrist-is required in early childhood. The findings support the importance of early detection of amblyopia before 36 months and no later than 48 months of age via screening with at least 1 comprehensive eye examination before age 5 years.

CONCLUSIONS

Vision screening performed by primary health care providers during routine well-baby/child visits and scheduled vaccinations is an essential part of the detection of ocular disease. However, this early detection potential is limited, and a full oculovisual assessment is also recommended before the child entering the school system. If amblyopia, strabismus, or other eye pathology is detected or suspected that is beyond the scope of the eye care professional examining the patient, a referral to the appropriate specialist can be made, allowing treatment to be initiated in a timely fashion.

Global prevalence of amblyopia and disease burden projections through 2040: a systematic review and meta-analysis

Purpose

Amblyopia is a leading cause of vision impairment among children and young adults. Individual studies showed significant variations in the prevalence of amblyopia in different regions and age groups. This study is to estimate the global prevalence of amblyopia by pooling its prevalence from the previous studies and to project the number of people affected through 2040.

Methods

We performed a systematic review and meta-analysis on the prevalence of amblyopia using data published before 20 October 2018. We estimated the prevalence rate of amblyopia and its 95% CI globally and by subgroups (eg, region and age). The prevalence data were applied to United Nations World Population Prospects to derive the projected number with amblyopia through 2040.

Results

A meta-analysis of 60 studies (1 859 327 subjects) showed that the pooled prevalence rate of amblyopia was 1.44% (95% CI 1.17% to 1.78%). Prevalences in Europe (2.90%) and North America (2.41%) were higher than in Asia (1.09%) and Africa (0.72%). The highest prevalence was found in subjects over 20 years old (3.29%). There was no difference in the prevalence between genders. We estimated 99.2 (95% CI 71.7 to 146.1) million people with amblyopia in 2019 worldwide, increasing to 175.2 (95% CI 81.3 to 307.8) million by 2030 and 221.9 (95% CI 83.7 to 429.2) million by 2040.

Conclusions

The amblyopia is becoming a significant vision problem worldwide. It is of great importance to design and implement amblyopia screening, treatment and related public health strategies.

Electrophysiological and Psychophysical Studies of Meridional Anisotropies in Children With and Without Astigmatism

Purpose

We investigated the pattern of meridional anisotropies, if any, for pattern onset-offset visual evoked potential (POVEPs) responses and psychophysical grating acuity (GA) in children with normal letter visual acuity (20/20 or better).

Methods

A total of 29 children (aged 3-9 years), nine of whom were astigmatic (AS), were recruited. Orientation-specific monocular POVEPs were recorded in response to sinewave grating stimuli oriented along the subjects' principal AS meridians. Horizontal and vertical gratings were designated Meridians 1 and 2, respectively, for nonastigmatic patients (Non-AS). Binocular POVEPs in response to the same stimuli, but oriented at 45°, 90°, 135°, and 180°, were recorded. Psychophysical GAs were assessed monocularly and binocularly along the same meridians using the same stimuli by a 2-alternative-forced-choice staircase technique. The C3 amplitudes and peak latencies of the POVEP and GAs were compared across meridians using linear mixed models (monocular) and ANOVA (binocular).

Results

There were significant meridional anisotropies in monocular C3 amplitudes regardless of astigmatism status (P = 0.001): Meridian 2 (mean ± SE Non-AS, 30.13 ± 2.07 μV; AS, 26.53 ± 2.98 μV) was significantly higher than Meridian 1 (Non-AS, 26.14 ± 1.87 μV; AS, 21.68 ± 2.73 μV; P = 0.019), but no meridional anisotropies were found for GA or C3 latency. Binocular C3 amplitude in response to horizontally oriented stimuli (180°, 29.71 ± 3.06 μV) was significantly lower than the oblique (45°, 36.62 ± 3 .05 μV; P = 0.03 and 135°, 35.95 ± 2.92 μV; P = 0.04) and vertical (90°, 37.82 ± 3.65 μV; P = 0.02) meridians, and binocular C3 latency was significantly shorter in response to vertical than oblique gratings (P ≤ 0.001).

Conclusions

Meridional anisotropy was observed in children with normal vision. The findings suggest that horizontal gratings result in a small, but significantly lower POVEP amplitude than for vertical and oblique gratings.

Choosing appropriate tools and referral criteria for vision screening of children aged 4-5 years in Canada: a quantitative analysis

OBJECTIVES

To assess the diagnostic accuracy of five vision screening tools used in a school setting using sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

DESIGN

We compared the results of the five best evidence-based screening tools available in 2014 to the results of a comprehensive eye exam with cycloplegic refraction by a licenced optometrist. Screening included Cambridge Crowded Acuity Cards, Plusoptix S12 and Spot photoscreeners, Preschool Randot Stereoacuity Test and the Pediatric Vision Scanner (PVS). Referral criteria followed AAPOS (2013) guidelines and published norms.

SETTING

A large school in Toronto, Canada, with 25 split classrooms of junior kindergarten (JK: 4 year olds) and senior kindergarten (SK: 5 year olds) children.

PARTICIPANTS

Over 2 years, 1132 eligible children were enrolled at the school. After obtaining parental consent, 832 children were screened. Subsequently, 709 children had complete screening and optometry exam data.

MAIN OUTCOME MEASURES

The presence/absence of a visual problem based on optometrist's assessment: amblyopia, amblyopia risk factors (reduced stereoacuity, strabismus and clinically significant refractive errors) and any other ocular problem (eg, nystagmus).

RESULTS

Overall, 26.5% of the screened children had a visual problem, including 5.9% with amblyopia. Using all five tools, screening sensitivity=84% (95% CI 78 to 89), specificity=49% (95% CI 44 to 53), PPV=37% (95% CI 33 to 42), and NPV=90% (95% CI 86 to 93). The odds of having a correct screening result in SK (mean age=68.2 months) was 1.5 times those in JK (mean age=55.6 months; 95% CI 1.1 to 2.1), with sensitivity improved to 89% (95% CI 80 to 96) and specificity improved to 57% (95% CI 50 to 64) among SK children.

CONCLUSIONS

A school-based screening programme correctly identified 84% of those kindergarten children who were found to have a visual problem by a cyclopleged optometry exam. Additional analyses revealed how accuracy varies with different combinations of screening tools and referral criteria.

Prevalence of vision impairment and refractive error in school learners in Calabar, Nigeria

Background: Uncorrected refractive error could negatively affect learning and academic performance, there is still inadequate information for planning school health.Aim: To determine the proportion of students with vision impairment because of uncorrected refractive error, and prevalent types among learners aged 10–18 years.Setting: The study site included two of 18 local government areas of the Cross River State in Nigeria, with 23 public and mission secondary schools.Methods: A two-stage cluster sampling method was used to enrol 4241 study participants from eight selected secondary schools.Results: The prevalence of vision impairment (presenting visual acuity worse than 6/12) was 7.9% (95% confidence interval [CI]: 7.17% – 8.6%). The prevalence of vision impairment because of refractive error was 7.2% (95% CI: 6.41% – 7.96%) in the better eye. Astigmatism was the predominant type of refractive error with a prevalence of 4.2% (95% CI: 3.6% – 4.8%), followed by myopia (1.72%; 95% CI: 1.3% – 2.1%) and hyperopia (1.3%; 95% CI: 0.9% – 1.6%). There were statistically significant differences in proportions of female participants who presented with myopic astigmatism (30.8%; p 0.012). Statistically significant difference in proportions was found in older (33.3%; p 0.0004) and male (29.6%; p 0.0003) participants who presented with hyperopic astigmatism compared to younger and female participants, respectively. Myopia accounted for 4.8% (95% CI: 4.2% – 5.5%) and was significantly higher in female participants (5.5%; p 0.033).Conclusion: Refractive error was the major cause of vision impairment and myopic astigmatism was the predominant type of refractive error among secondary school children in Calabar.

Evidence-based preschool-age vision screening: health policy considerations

Background

There are many causes of visual impairment, and even blindness, which are treatable or at least preventable. Two such conditions are strabismus (crossed-eye, squint) and refractive error (visual image not focused on the most sensitive part of the retina). If these are not detected and corrected at an early age, they can lead to an irreversible impairment known as amblyopia (lazy eye). Pediatric vision screening and subsequent treatment for amblyopia and amblyogenic risk factors are thus key to preventing vision loss. Furthermore, vision screening can detect moderate to high hyperopia, which has been found to be associated with poor school readiness.

Evidence-based recommendations call for screening children at 3–5 years of age; they are old enough to cooperate, but still within the window of effective intervention. However, these recommendations have yet to be universally implemented as the standard of care.

Methods

This paper integrates a review of the literature and the international experience of preschool vision screening with the findings from a preliminary feasibility study of expanded screening in Israel to formulate a discussion of the current health policy challenge in Israel and the options for addressing it. The advantages and disadvantages of various venues for vision screening are discussed.

Findings

Screening by optometrists in Mother and Child Health Centers, as implemented in a recent pilot project in the Jerusalem District, would allow the most comprehensive testing. Photo-screening in preschools would reach the most children, but at the cost of missing hyperopia (farsightedness). Either approach would probably constitute improvements over the current situation. The relative strengths of the two approaches depends in part on the ability to purchase automatic screening equipment (and the efficacy of that equipment) vs. the ongoing cost of paying trained personnel.

Conclusions

Further research should be conducted in Israel to determine the prevalence of refractive errors, so that best practices can be established for Israel’s population and social needs. In the interim, the Ministry of Health should promptly implement the inclusion of preschool visions screening for children in the approved “basket of services” covered by the National Health Insurance Laws, using photo-screening, including collection of the clinical data.

Electronic supplementary material

The online version of this article (10.1186/s13584-019-0339-z) contains supplementary material, which is available to authorized users.

Analysis of the current preschool vision screening in Denmark

PURPOSE

To analyse the current vision screening programme for children attending school with respect to identifying children with significant refractive errors.

METHODS

A total of 950 children from the municipality of Roskilde, Denmark, were invited to participate in a cross-sectional study of vision screening. 447 children aged 4.5-7 years participated in the study. The children completed a vision screening and a full eye examination. The vision screening consisted of visual acuity at distance (VA), visual acuity at distance with +2.0 glasses (VA+2), visual acuity at near (VAnear) and Lang II stereotest. A LogMAR-based picture chart was used for the vision testing. Significant refractive errors were defined as hyperopia ≥+3.5 D, myopia >1.0 D, astigmatism ≥1.25 D and anisometropia >1.0 D.

RESULTS

Using receiver operating characteristic (ROC) curves, we could compare the efficiency of VA, VA+2, VAnear, VA in combination with VA+2 and VA in combination with VAnear. Area under the curve (AUC) for VA, VA combined with VA+2 and VA combined with VAnear was 0.841, 0.857 and 0.857, respectively, that is all classified as 'very good' screening tools, whereas VA+2 and VAnear as single screening tools were classified as 'good' with AUC of 0.704 and 0.775, respectively. Using the optimal cut-off limit from the ROC curves, VA above 0.05 LogMAR as cut-off limit showed a sensitivity of 85.2% with a specificity of 74.9%. A slightly higher sensitivity could be found when combining screening tests, but with declining specificities.

CONCLUSION

Visual acuity at distance with the use of LogMAR-based charts is the optimal screening tool of choice; only minor improvements can be obtained combining with other tests.

Longitudinal Changes in Spherical Equivalent of Moderate to High Hyperopia: 2- to 8-Year Follow-Up of Children at an Initial Age of 5.5 to 8.4 Years

Purpose

Moderate to high hyperopia is associated with visual deficits. Currently, to our knowledge no study has reported its longitudinal refraction change in a large sample of schoolchildren. We investigated the longitudinal changes in spherical equivalent (SE) refractive error among schoolchildren with moderate to high hyperopia.

Methods

Medical records of patients seeking refractions at Zhongshan Ophthalmic Center between 2009 and 2017 were reviewed retrospectively. Eligible criteria included hyperopia ≥+2.00 diopters (D) at an initial age of 6 to 8 years, at least three visits, and at least a 2-year follow-up. Individual pattern of refraction development was evaluated based on the mean rate of change in SE. Mixed-effect regression analysis was used to explore factors associated with the rate of change.

Results

A total of 1769 cases were identified. Median initial age was 6.4 (interquartile range [IQR], 5.9 to 7.1) years and median age at the final visit was 10.1 (IQR, 8.9 to 11.5) years. Median initial SE was +3.13 (IQR, +2.38 to +5.25) D. On average, participants experienced a myopic shift of -0.35 ± 0.27 D/year. A considerable number of eyes (721, 40.8%) demonstrated a longitudinal change of less than ±0.25 D/year and approximately 1 of 3 (611/1769) eyes demonstrated a change of >-0.50 and ≤-0.25 D/year. Children with greater initial hyperopia (β = -0.02, P < 0.001) experienced significantly faster reduction in hyperopic refraction. Age and sex had statistically significant but clinically insignificant impacts on the rate of hyperopia reduction.

Conclusions

Variation exists in the refraction development of schoolchildren with moderate to high hyperopia. A considerable percentage of eyes demonstrates longitudinally stable refraction.

Contralateral eye comparison of the long-term visual quality and stability between implantable collamer lens and laser refractive surgery for myopia

Purpose

To investigate the long‐term visual quality and stability of implantable collamer lens (ICL) and laser refractive surgery (LRS) for myopia.

Methods

This study comprised 52 eyes of 26 high‐myopia anisometropia patients who were suitable for surgical treatment. In each patient, the higher‐myopia eye was implanted with ICL and the lower‐myopia eye was treated with LRS. The patients were followed for 3 years. During that time period, uncorrected (UDVA) and corrected distance visual acuity (CDVA), refraction, wavefront aberration and visual quality were evaluated.

Results

The spherical equivalent refractive error changed from −14.11 ± 3.39 D preoperatively to −1.27 ± 1.05 D 3 years after ICL implantation and from −8.75 ± 2.76 D to −1.12 ± 1.30 D after LRS. The changes in refractive error from 1 month to 3 years were −0.52 and −0.77 D for the ICL and LRS groups, respectively. The safety indices (postoperative CDVA/preoperative CDVA) were 1.84 ± 1.00 and 1.32 ± 0.40, and the efficacy indices (postoperative UDVA/preoperative CDVA) were 1.40 ± 1.10 and 1.11 ± 0.44, respectively. The postoperative coma, spherical and total higher‐order aberrations in the ICL group were lower than those in the LRS group.

Conclusion

Both ICL implantation and LRS are safe and effective procedures for myopia with suitable indications, but ICL implantation is more stable. Fewer induced aberrations are gained after ICL implantation.

[Do children with strabismus receive ophthalmic treatment? : Results from the KiGGS (German Health Interview and Examination Survey for Children and Adolescents) baseline survey (2003-2006)]

INTRODUCTION

Strabismus is a common cause for amblyopia and affected children need regular ophthalmic care. This study evaluated the frequency of ophthalmic care in children suffering from strabismus and analyzed associated factors.

METHODS

The data of the German Health Interview and Examination Survey for Children and Adolescents from the Robert Koch Institute (KiGGS, baseline survey 2003-2006, N = 17,640) were analyzed. Details on the presence of strabismus and the frequency of ophthalmic care were documented from information provided by the parents. Children aged 1-6 years were included. The relationship between strabismus and ophthalmic care in the previous 12 months was analyzed using multivariable logistic regression analysis and adjusted for age, sex, socioeconomic status, migration background, region and participation in regular pediatric check-ups.

RESULTS

A total of 5247 children were included in this study of which 3.0% (N = 175) were reported by the parents as suffering from strabismus. Ophthalmic care within the last 12 months was reported by 66.9% of the parents (95% confidence interval [CI] 54.7-77.2%) of children with strabismus and was more frequent compared to those without strabismus (19.7%, 95% CI 18.2-21.3%). Of the children with strabismus 33.8% had visited an ophthalmologist in the last 12 months once, 33.1% twice, 12.6% three times, 13.3% four times and 7.2% more than four times. There was a relationship between strabismus (odds ratio [OR] = 9.21, 95% CI 5.44-15.6) and ophthalmic care during the preceding year.

CONCLUSION

In Germany approximately one third of children with strabismus did not receive ophthalmic care within the previous year. This underlines the need for improvements in ophthalmic care in children with strabismus.

A Randomized Clinical Trial of Immediate versus Delayed Glasses for Moderate Hyperopia in 1- and 2-Year-Olds

PURPOSE

Two strategies were compared for managing moderate hyperopia without manifest strabismus among 1- and 2-year-old children: (1) immediate prescription of glasses versus (2) observation without glasses unless reduced distance visual acuity (VA), reduced stereoacuity, or manifest strabismus.

DESIGN

Prospective randomized clinical trial.

PARTICIPANTS

A total of 130 children aged 1 to 2 years with hyperopia between +3.00 diopters (D) and +6.00 D spherical equivalent (SE) in at least 1 eye, anisometropia ≤1.50 D SE, and astigmatism ≤1.50 D based on cycloplegic refraction and no manifest strabismus.

METHODS

Participants were randomly assigned to glasses (1.00 D less than full cycloplegic hyperopia) versus observation and followed every 6 months for 3 years. Glasses were prescribed to those assigned to observation if they met prespecified deterioration criteria of distance VA or near stereoacuity below age norms, or development of manifest strabismus.

MAIN OUTCOME MEASURES

At the 3-year primary outcome examination, participants were classified as failing the randomized management regimen if distance VA or stereoacuity was below age norms or manifest strabismus was observed (each with and without correction in trial frames, confirmed by masked retest, irrespective of whether deterioration had occurred previously), or if strabismus surgery had been performed.

RESULTS

Of the 106 participants (82%) completing the 3-year primary outcome examination, failure occurred in 11 (21%) of 53 in the glasses group and 18 (34%) of 53 in the observation group (difference = -13%; 95% confidence interval [CI], -31 to 4; P = 0.14). Sixty-two percent (95% CI, 49-74) in the observation group and 34% (95% CI, 23-48) in the glasses group met deterioration criteria (requiring glasses if not wearing).

CONCLUSIONS

For 1- and 2-year-olds with uncorrected moderate hyperopia (+3.00 D to +6.00 D SE), our estimates of failure, after 3 years of 6-month follow-ups, are inconclusive and consistent with a small to moderate benefit or no benefit of immediate prescription of glasses compared with careful observation (with glasses only if deteriorated).

The prevalence of amblyopia in Iran: A systematic review

PURPOSE

The aim of this study was to determine the prevalence of amblyopia in the population of Iran.

METHODS

This article is a systematic review. A comprehensive search was conducted in PubMed, Scopus, Science Direct, Ovid, Web of Science, SID, Magiran, with appropriate terms. Information related to the sample size and the prevalence of amblyopia was extracted and summarized in tables. Analysis was performed using STATA software.

RESULTS

From 551 articles that were originally extracted from the databases, 31 articles met the criteria for entering the review. These studies were conducted in different regions of Iran. The prevalence of amblyopia in different regions varied between 0.19 and 3.69%. Study results were heterogeneous (I2 = 99.7%), and therefore, a meta-analysis was not done.

CONCLUSIONS

The prevalence of amblyopia in Iran is very different. In addition to conducting national screenings, it is necessary to report the incidence of amblyopia and its related factors in different parts of the country.

Evaluation of a smartphone photoscreening app to detect refractive amblyopia risk factors in children aged 1-6 years

Purpose

To determine the specificity and sensitivity of a smartphone app (GoCheckKids [GCK] used as a photoscreening tool on the iPhone 7 to detect refractive amblyopia risk factors in children aged 1–6 years.

Participants and methods

A prospective, multicenter, 10-month evaluation of children aged 1–6 years old who underwent photoscreening with the GCK app to detect amblyopia risk factors. The first acceptable quality photograph of each study subject was evaluated by trained technicians using GCK’s proprietary automated image processing algorithm to analyze for amblyopia risk factors. Trained graders, masked to the cycloplegic clinical data, remotely reviewed photographs taken with the app and compared results to the gold standard pediatric ophthalmology examinations using the 2013 American Association for Pediatric Ophthalmology & Strabismus amblyopia risk factor guidelines. Primary outcome was the ability of the GCK app to identify amblyopia risk factors compared to the cycloplegic refraction.

Results

There were 287 patient images analyzed. The overall sensitivity and specificity in detecting amblyopia risk factors were 76% and 85%, respectively using manual grading. The overall automated grading results had a sensitivity and sensitivity in detecting amblyopia risk factors of 65% and 83%, respectively.

Conclusion

The GCK smartphone app is a viable photoscreening device for the detection of amblyopia risk factors in children aged 1–6 years.

Efficacy and outcomes of a summer-based pediatric vision screening program

PURPOSE

To investigate the prevalence of decreased visual acuity and uncorrected refractive error in school-aged children participating in summer programs.

METHODS

During the summers of 2014-2016, Wills Eye Hospital collaborated with summer programs in Philadelphia to provide vision screenings for underserved children. Parental consent was obtained prior to vision screening. Fail criteria included children in grades K-1 (ages 5-6) with visual acuity worse than 20/40 in either eye, children in grades 2-6 (ages 7-13) with visual acuity worse than 20/30 in either eye, or children with ≥2 lines of interocular difference. If decreased visual acuity was correctable to ≥20/30 by the onsite optometrist, two pairs of free eyeglasses were provided. Children with other ocular abnormalities were referred to pediatric ophthalmology.

RESULTS

Of 1,627 children screened, 360 children (22.1%) did not pass vision screening, and 64 (3.9%) were referred. The prevalence of decreased distance visual was 34.1%. Younger children were more likely to have worse visual acuity than older children (OR = 0.943; P = 0.023; 95% CI, 0.896-0.992). Myopia (73%), astigmatism (56.8%), hyperopia (15.5%), spherical anisometropia (12.5%), and cylindrical anisometropia (11.9%) presented in the 303 children who underwent a manifest refraction. Myopia increased with age (OR = 0.818; P = 0.001; 95% CI, 0.724-0.922), whereas astigmatism decreased (OR = 0.817; P < 0.001; 95% CI, 0.728-0.913) with age. Two pairs of glasses were provided to 301 children.

CONCLUSIONS

Partnership with summer programs and other community initiatives to provide vision screenings facilitates access to eye care ultimately aimed at improving social functioning and academic performance.

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

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

Association between mode of delivery and astigmatism in preschool children

PURPOSE

To determine whether mode of delivery has any impact on astigmatism.

METHODS

This case-control study was performed in the Department of Ophthalmology in 2015. Exposure was mode of delivery [vaginal delivery (VD) or caesarean section (CS), which here included both elective and emergency CS]. Outcome was astigmatism (≥2.5 D), which was determined by cycloplegic refraction. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were computed to assess the associations between mode of delivery and astigmatism from logistic regression models.

RESULTS

Of the 659 children studied here (341 boys; mean age, 4.37 years), 440 were born by CS and 219 by VD. The incidence of severe astigmatism (≥2.5 D) in the CS and VD groups was 22.06% and 13.24%, respectively. Children delivered by CS had a 77.9% higher risk of severe astigmatism compared with vaginally delivered children (OR = 1.779; 95% CI, 1.121 to 2.824). After dividing CS into elective CS and emergency CS, children delivered by elective CS had an 87.3% increased risk of severe astigmatism (OR = 1.873; 95% CI, 1.157 to 3.032), but children delivered by emergency CS did not differ from vaginally delivered children. In addition, the children whose mothers had histories of breastfeeding had a 44.6% lower risk of severe astigmatism than children whose mother did not breastfeed them (OR = 0.554, 95% CI, 0.335-0.914).

CONCLUSION

Birth by CS, especially elective CS, increases the risk of severe astigmatism (≥2.50 D) in childhood.

Investigating the Visual Status Of Preschool Children in Riyadh, Saudi Arabia

PURPOSE:

The purpose of the study was to explore the vision status of preschool children aged 3–6 years in Al Riyadh and to identify children at risk of amblyopia.

MATERIALS AND METHODS:

This was a cross-sectional population-based study. Visual acuity (VA) was measured using 15-line Lea symbols, refractive error was assessed using the Mohindra near retinoscopy technique, and peak contrast sensitivity (CS) was measured with the aid of the numerical CS test. We recruited 335 children, with their parents' written consent, from 14 kindergartens.

RESULTS:

A total of 335 children were recruited; 42 children (13%) exhibited reduced VA (Median [interquartile ranges (IQRs)], 0.00 [0.01]); most were emmetropic (87.7%). Myopia (4.2%), hyperopia (8.1%), and astigmatism (20%) were also observed. Most children had normal CSs. About 14% of children were at risk of amblyopia. It has been observed that 26% of families have some kind of refractive error.

CONCLUSIONS:

It is important to perform vision screening of preschoolers. Early detection of abnormalities in refractive errors could help to minimize the effect of visual impairment.

School-based assessment of amblyopia and strabismus among multiethnic children in rural China

We aimed to determine the prevalence and possible ethnic variations in strabismus and amblyopia among multiethnic school-aged children in rural China. A total of 9,263 children (4,347 Han, 3,352 Yi, 799 Dai and 765 Bai) aged 6 to 14 years were analyzed. Comprehensive eye examinations including monocular distance visual acuity, anterior segment examination, autorefraction, cover testing and ocular motility were conducted. Manifested strabismus was detected in 3.53% of the overall population. The prevalence of strabismus was 3.29% in Han, 4.12% in Yi, 2.25% in Dai, and 3.66% in Bai ethnic groups with marginally inter-ethnic differences (P = 0.046). There was an increasing trend in the prevalence of strabismus with increasing age (P < 0.001). Amblyopia affected 132 children (1.43%) overall, with no statistical differences in gender and age. The prevalence of amblyopia was highest in Dai ethnic group (2.00%) and lowest in ethnic Yi ethnic group (1.04%) with no significant difference being detected (P = 0.062). Refractive error and strabismus were the two major factors associated with amblyopia. No significant ethnic differences in strabismus and amblyopia among Chinese ethnic minorities were observed. Refractive error and strabismus were the major causes for amblyopia in rural Chinese children.

New pediatric risk factors for amblyopia: strabismic versus refractive

PURPOSE

To assess the role of risk factors for amblyopia, such as family history and neonatal background, for the prediction of either strabismic amblyopia or refractive amblyopia.

METHODS

In this retrospective case-control model, the study population included all children born at the Hospital de Braga during 1997-2012 (3 to 18 years old) with ophthalmologic consultation in 2014. Data collection was performed from the clinical database and through telephone questionnaire surveys.

RESULTS

A total of 298 (50%) controls and 298 (50%) cases (120 [40.3%] strabismic amblyopia and 178 [59.7%] refractive amblyopia) were analyzed. A significantly lower birthweight was detected in patients with strabismic amblyopia (mean 2,961 g [95% confidence interval (CI) 2,827-3,096]) compared to controls (mean 3,198 g [95% CI 3,125-3,271]) (p = 0.002). Five-minute Apgar was significantly lower in patients with strabismic amblyopia (mean 9.57 [95% CI 9.37-9.77]) than in controls (mean 9.83 [95% CI 9.77-9.90]) (p = 0.004) or patients with refractive amblyopia (mean 9.79 [95% CI 9.69-9.89]) (p = 0.031). Family history of either amblyopia or strabismus was associated with amblyopia (χ² [2, n = 562] = 12.66; p = 0.002; Cramer V = 0.150; χ² [2, n = 561] = 11.0; p = 0.004; Cramer V = 0.140), but was significantly more associated with strabismic amblyopia (p = 0.0023 and p = 0.0032) than with refractive amblyopia (p = 0.48 and p = 0.015, respectively). Multinomial logistic regression model explained 50.8% of the variance in amblyopia development. Low 5-minute Apgar had a relevant odds ratio (OR) for either strabismic amblyopia (OR 3.44; p = 0.066) or refractive amblyopia (OR 3.30; p = 0.077).

CONCLUSIONS

This division in amblyopia subtypes gives a new perspective of the risk factors for amblyopia, with family history and some obstetrician/neonatal outcomes appearing to be more relevant in strabismic amblyopia. Educating health care providers to recognize these risk factors can result in an early ophthalmologic referral.

Prevalence of amblyopia and its association with refraction in Chinese preschool children aged 36-48 months

PURPOSE

To determine the prevalence of amblyopia and its association with refraction in Chinese preschool children.

METHODS

The Yuhuatai Pediatric Eye Disease Study, a cross-sectional, population-based study, was conducted in children aged 36-48 months in Yuhuatai District, Nanjing, China, in 2015. Visual acuity was measured in 1695 eligible children.

RESULTS

Of the 1695 subjects, manifested amblyopia was detected in 25 children (1.47%, 95% CI 0.90% to 2.05%), including 11 and 14 with bilateral and unilateral amblyopia, respectively. Amblyopia prevalence did not differ by gender (p=0.77). Significant refractive errors were found in 22 (88.0%) of children with amblyopia, and strabismus was found in 6 (24.0%) children with amblyopia. In multivariate analysis, amblyopia was significantly associated with hyperopia (≥+2.00 dioptres (D); OR 8.81, 95% CI 3.27 to 23.69, p<0.0001), astigmatism (≥2.00 D; OR 17.90, 95% CI 6.78 to 47.21, p<0.0001) and anisometropia (≥2.00 D; OR 5.87, 95% CI 1.52 to 22.77, p<0.05).

CONCLUSIONS

The prevalence of amblyopia in children 36-48 months old in Eastern China was 1.47%. The refractive error is a major risk factor for amblyopia.

Amblyopia and strabismus: trends in prevalence and risk factors among young adults in Israel

Aims

To estimate the prevalence of amblyopia, present strabismus and amblyopia risk factors (ARFs) among young adults in Israel and to analyse trends over time of prevalence rates.

Methods

We conducted a cross-sectional study including 107 608 pre-enlistees aged 17.4±0.6 years born between 1971 and 1994. Across the birth years, the following trends of prevalence rates among young adults were analysed: prevalence of amblyopia, prevalence of strabismus, severity of amblyopia and prevalence of ARFs (strabismsus, anisometropia and isoametropia). Unilateral amblyopia was defined as best corrected visual acuity (BCVA) of <0.67 (6/9) in either eye or as an interocular difference of two lines or more. Bilateral amblyopia was defined as BCVA of <0.67 (6/9) in both eyes. The severity of amblyopia was classified as mild (BCVA ≥0.5 [6/12]), moderate (BCVA <0.5 [6/12] and ≥0.25 [6/24]) or severe (BCVA <0.25 [6/24]).

Results

The prevalence of young adulthood amblyopia declined by 33%, from 1.2% to 0.8% (R2=0.87, p<0.001) across 24 birth years. This decline may be due to a drop in unilateral amblyopia from 1% to 0.6% (R2=0.93, p<0.001), while the prevalence of bilateral amblyopia remained stable (0.2%, p=0.12). The decline in amblyopia was apparent in mild and moderate amblyopia, but not in severe amblyopia. Strabismus and anisometropia were detected in 6–12% and 11–20% of subjects with unilateral amblyopia, respectively, without significant trends. Strabismic amblyopia remained constant in the entire population across years. Isoametropia was detected in 46–59% of subjects with bilateral amblyopia without a significant trend across birth years. Prevalence of strabismus in the study population decreased by 50%, from 1.2% to 0.6% (R2=0.75, p<0.001). In subjects with present strabismus, the prevalence of mild unilateral amblyopia increased, while moderate or severe unilateral amblyopia remained relatively stable.

Conclusion

Among young adults, the prevalence of unilateral amblyopia, as well as the prevalence of present strabismus, decreased significantly over a period of a generation. The prevalence of strabismic, bilateral or severe (both unilateral and bilateral) amblyopia remained stable. The establishment of the national screening programme for children and the improved utility of treatment for amblyopia and strabismus coincide with these trends. Thus, it is possible that these early interventions resulted in modification of the ‘natural history’ of these conditions and their prevalence in adolescence.

Comparative electrophysiological responses in anisometropic and strabismic amblyopic children

Purpose

To compare anisometropic hypermetropic amblyopic and strabismic amblyopic responses to pattern electroretinogram (PERG) and pattern visual evocated potential (PVEP).

Materials and methods

Fifty-six patients – 18 hypermetropic anisometropic amblyopic children (mean age 9.70±2.5 years), 19 strabismic amblyopic children (mean age 10.30±2.6 years) and 19 normal emetropic subjects (mean age 10.10±2.2 years) – were enrolled in this study. After routine ophthalmic examination, PERG and PVEP were recorded in response to checks reversed at the rate of two reversals/second stimulating macular area.

Results

The difference between hypermetropic anisometropic amblyopia and strabismus amblyopia with respect to P100/P50/N95 wave latencies (P=0.055/0.855/0.132) and P100/P50/N95 amplitudes (P=0.980/0.095/0.045) was not statistically significant. However, there was a significant statistical difference between strabismic amblyopia group and controls for P100/P50/N95 latencies (P=0.000/0.006/0.004).

Conclusion

Our findings indicated that despite clinical differences between anisometropic amblyopic and strabismic amblyopic patients, no differences were found in the responses of PVEP and PERG. The abnormal components of the PVEP and PERG in amblyopic subjects could reflect a retinal dysfunction in the visual pathway.

Inequities in visual health and health services use in a rural region in Spain

OBJECTIVE

To analyse perceived visual health and health services use in a rural population in relation to socioeconomic characteristics and compared with the general population in Spain.

METHOD

Cross-sectional study in a rural population using a structured questionnaire including questions comparable to the Spanish National Health Survey (2012). A descriptive analysis was carried out through the calculation of frequencies and prevalence, the χ² test for independent variables, contrasts of proportions and logistic regression to obtain associations between the rural and general populations and socioeconomic variables.

RESULTS

For the rural population studied, the prevalence of poor perceptions of visual health is 40.8% in men and 39.4% in women, and is strongly associated with age, employment situation, income and presence of chronic diseases (p ˂0.001). Compared with the general population, the rural population has a higher risk of presenting with serious difficulties related to farsightedness (OR: 2.56; 95% CI: 1.32-4.95) and make less use of optical correction (OR: 0.57; 95%CI: 0.44-0.74). The use of health services is not sufficient for adequate prevention, particularly in diabetics. For those affected by poor vision, the distance to travel to receive an eye exam, the belief that eyesight problems come with age and the cost of glasses are the principal reasons used to explain why eyesight problems are not resolved.

CONCLUSIONS

The rural population presents worse visual health that is influenced by social and economic factors. Improving accessibility and reducing barriers is essential to tackle avoidable visual disability and reduce health inequities.

Comparison of cycloplegic refraction between Grand Seiko autorefractor and Retinomax autorefractor in the Vision in Preschoolers-Hyperopia in Preschoolers (VIP-HIP) Study

PURPOSE

To evaluate the agreement of cycloplegic refractive error measures between the Grand Seiko and Retinomax autorefractors in 4- and 5-year-old children.

METHODS

Cycloplegic refractive error of children was measured using the Grand Seiko and Retinomax during a comprehensive eye examination. Accommodative error was measured using the Grand Seiko. The differences in sphere, cylinder, spherical equivalent (SE) and intereye vector dioptric distance (VDD) between autorefractors were assessed using the Bland-Altman plot and 95% limits of agreement (95% LoA).

RESULTS

A total of 702 examinations were included. Compared to the Retinomax, the Grand Seiko provided statistically significantly larger values of sphere (mean difference, 0.34 D; 95% LoA, -0.46 to 1.14 D), SE (mean, 0.25 D; 95% LoA, -0.55 to 1.05 D), VDD (mean, 0.19 D; 95% LoA, -0.67 to 1.05 D), and more cylinder (mean, -0.18 D; 95% LoA, -0.91 to 0.55 D). The Grand Seiko measured ≥0.5 D than Retinomax in 43.1% of eyes for sphere and 29.8% of eyes for SE. In multivariate analysis, eyes with SE of >4 D (based on the average of two autorefractors) had larger differences in sphere (mean, 0.66 D vs 0.35 D; P < 0.0001) and SE (0.57 D vs 0.26 D; P < 0.0001) than eyes with SE of ≤4 D.

CONCLUSIONS

Under cycloplegia, the Grand Seiko provided higher measures of sphere, more cylinder, and higher SE than the Retinomax. Higher refractive error was associated with larger differences in sphere and SE between the Grand Seiko and Retinomax.

Sensitivity and Specificity of Preschool Vision Screening in Iran

BACKGROUND

To determine the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the National Vision Screening Program for 7 yr old children in Iran.

METHODS

In this cross-sectional study, eight cities in Iran were selected through multistage cluster sampling. Selected cities were Sari, Birjand, Ardabil, Mashhad, Bandar Abbas, Dezful, Yazd, and Arak, in Iran in 2013. Totally, 4614 schoolchildren were selected, 4106 of which participated in the study. An optometrist at the school site conducted all vision tests. Results were compared against those recorded on each child's health card. Those with an uncorrected visual acuity worse than 20/25 in at least one eye screened positive for a vision problem.

RESULTS

8.49% [95% confidence interval, 7.65 to 9.39] of the examinees had a vision problem. The sensitivity rate of the school entry screening was 38.15% (95% CI, 33.01 to 43.50) and the specificity rate was 93.11 (95%CI 92.25 to 93.90). The positive and negative predictive values were 33.93 (29.24 to 38.88) and 94.19 (93.39 to 94.93), respectively. Sensitivity and specificity rates did not significantly differ between boys and girls. For the uncorrected visual acuity tested by public health care workers compared to optometrists, the area under the ROC surface was 0.741 (P<0.001). The best-associated criterion was an uncorrected visual acuity more than 0.05 LogMAR with 67.3% sensitivity and 74.7% specificity.

CONCLUSION

The validity of the school entry vision screening by health workers is low. To reduce false negative rates, some supplementary examinations such as refraction and near visual acuity measurements as well as further training of screeners should be considered.

Refractive Errors and Amblyopia in the UCLA Preschool Vision Program; First Year Results

PURPOSE

To report the outcomes of full ophthalmic examination for preschool children in LA County who failed screening with the Retinomax Autorefractor.

DESIGN

Retrospective, cross-sectional study.

METHODS

Between August 2012 and May 2013, the University of California Los Angeles (UCLA) preschool vision program screened 11 260 preschool children aged 3-5 years in Los Angeles County using the Retinomax Autorefractor only. Of those, 1007 children who failed the screening were examined by an ophthalmologist on the UCLA Mobile Eye Clinic. Data from the eye examination were recorded for all children. Amblyopia was defined as unilateral if there was ≥2 line interocular difference in the best-corrected visual acuity (BCVA) and as bilateral if BCVA was <20/50 for children <4 years old and <20/40 for children ≥4 years old.

RESULTS

Glasses were prescribed for 740 (74%) of those examined. Uncorrected visual acuity for all examined children was 0.4 ± 0.2 (logMAR mean ± SD), and BCVA was 0.2 ± 0.1. Of the 88% who underwent cycloplegia, 58% had hyperopia (spherical equivalent [SE] ≥+0.50 diopter [D]), mean of +2.50 D, and 21% had myopia (SE ≤-0.50 D), mean of -1.40 D. A total of 69% had astigmatism ≥1.50 D, mean of 1.97 D (range 0-5.75). Spherical and cylindrical anisometropia ≥1.00 D were each found in 26% of those examined. Refractive amblyopia was found in 9% of those examined, or 0.8% of the original population. Of the amblyopic subjects, 77% were unilateral.

CONCLUSIONS

Screening of preschoolers with the Retinomax led to diagnosis and early treatment of uncorrected refractive errors and amblyopia. By treating children early, amblyopia may be prevented, quality of life improved, and academic achievements enhanced.

Zagreb Amblyopia Preschool Screening Study: near and distance visual acuity testing increase the diagnostic accuracy of screening for amblyopia

AIM

To present and evaluate a new screening protocol for amblyopia in preschool children.

METHODS

Zagreb Amblyopia Preschool Screening (ZAPS) study protocol performed screening for amblyopia by near and distance visual acuity (VA) testing of 15 648 children aged 48-54 months attending kindergartens in the City of Zagreb County between September 2011 and June 2014 using Lea Symbols in lines test. If VA in either eye was >0.1 logMAR, the child was re-tested, if failed at re-test, the child was referred to comprehensive eye examination at the Eye Clinic.

RESULTS

78.04% of children passed the screening test. Estimated prevalence of amblyopia was 8.08%. Testability, sensitivity, and specificity of the ZAPS study protocol were 99.19%, 100.00%, and 96.68% respectively.

CONCLUSION

The ZAPS study used the most discriminative VA test with optotypes in line as they do not underestimate amblyopia. The estimated prevalence of amblyopia was considerably higher than reported elsewhere. To the best of our knowledge, the ZAPS study protocol reached the highest sensitivity and specificity when evaluating diagnostic accuracy of VA tests for screening. The pass level defined at ≤0.1 logMAR for 4-year-old children, using Lea Symbols in lines missed no amblyopia cases, advocating that both near and distance VA testing should be performed when screening for amblyopia.

Visual Function of Moderately Hyperopic 4- and 5-Year-Old Children in the Vision in Preschoolers - Hyperopia in Preschoolers Study

PURPOSE

To compare visual performance between emmetropic and uncorrected moderately hyperopic preschool-age children without strabismus or amblyopia.

DESIGN

Cross-sectional study.

METHODS

setting: Multicenter, institutional. patient or study population: Children aged 4 or 5 years. intervention or observation procedures: Visual functions were classified as normal or reduced for each child based on the 95% confidence interval for emmetropic individuals. Hyperopic (≥3.0 diopters [D] to ≤6.0 D in the most hyperopic meridian; astigmatism ≤1.50 D; anisometropia ≤1.0 D) and emmetropic status were determined by cycloplegic autorefraction.

MAIN OUTCOME MEASURES

Uncorrected monocular distance and binocular near visual acuity (VA); accommodative response; and near random dot stereoacuity.

RESULTS

Mean (± standard deviation) logMAR distance visual acuity (VA) among 248 emmetropic children was better than among 244 hyperopic children for the better (0.05 ± 0.10 vs 0.14 ± 0.11, P < .001) and worse eyes (0.10 ± 0.11 vs 0.19 ± 0.10, P < .001). Mean binocular logMAR near VA was better in emmetropic than in hyperopic children (0.13 ± 0.11 vs 0.21 ± 0.11, P < .001). Mean accommodative response for emmetropic children was lower than for hyperopic subjects for both Monocular Estimation Method (1.03 ± 0.51 D vs 2.03 ± 1.03 D, P < .001) and Grand Seiko (0.46 ± 0.45 D vs 0.99 ± 1.0 D, P < .001). Median near stereoacuity was better in emmetropic than in than hyperopic children (40 sec arc vs 120 sec arc, P < .001). The average number of reduced visual functions was lower in emmetropic than in hyperopic children (0.19 vs 1.0, P < .001).

CONCLUSIONS

VA, accommodative response, and stereoacuity were significantly reduced in moderate uncorrected hyperopic preschool children compared to emmetropic subjects. Those with higher hyperopia (≥4 D to ≤6 D) were at greatest risk, although more than half of children with lower magnitudes (≥3 D to <4 D) demonstrated 1 or more reductions in function.

Crowded letter and crowded picture logMAR acuity in children with amblyopia: a quantitative comparison

Aims

Clinically, picture acuity tests are thought to overestimate visual acuity (VA) compared with letter tests, but this has not been systematically investigated in children with amblyopia. This study compared VA measurements with the LogMAR Crowded Kay Picture test to the LogMAR Crowded Keeler Letter acuity test in a group of young children with amblyopia.

Methods

58 children (34 male) with amblyopia (22 anisometropic, 18 strabismic and 18 with both strabismic/anisometropic amblyopia) aged 4–6 years (mean=68.7, range=48–83 months) underwent VA measurements. VA chart testing order was randomised, but the amblyopic eye was tested before the fellow eye. All participants wore up-to-date refractive correction.

Results

The Kay Picture test significantly overestimated VA by 0.098 logMAR (95% limits of agreement (LOA), 0.13) in the amblyopic eye and 0.088 logMAR (95% LOA, 0.13) in the fellow eye, respectively (p<0.001). No interactions were found from occlusion therapy, refractive correction or type of amblyopia on VA results (p>0.23). For both the amblyopic and fellow eyes, Bland-Altman plots demonstrated a systematic and predictable difference between Kay Picture and Keeler Letter charts across the range of acuities tested (Keeler acuity: amblyopic eye 0.75 to −0.05 logMAR; fellow eye 0.45 to −0.15 logMAR). Linear regression analysis (p<0.00001) and also slope values close to one (amblyopic 0.98, fellow 0.86) demonstrate that there is no proportional bias.

Conclusions

The Kay Picture test consistently overestimated VA by approximately 0.10 logMAR when compared with the Keeler Letter test in young children with amblyopia. Due to the predictable difference found between both crowded logMAR acuity tests, it is reasonable to adjust Kay Picture acuity thresholds by +0.10 logMAR to compute expected Keeler Letter acuity scores.

Vision Screening of Younger School Children by School Teachers: A Pilot Study in Udaipur City, Western India

PURPOSE

To assess the reliability of school teachers for vision screening of younger school children and to study the pattern of vision problems.

METHODS

In this cross-sectional study, trained school teachers screened 5,938 school children aged 3 to 8 years for vision and ocular disorders. Children were cross screened by professionals to assess the reliability of the teachers in vision screening and detecting ocular disorders in these children. The pattern of visual acuity, ametropia and ocular disorders was studied.

RESULTS

Sensitivity and specificity of the vision screening by school teachers was 69.2% (95% CI: 66.8-71.5%) and 95.3% (95% CI: 94.5-95.8%), respectively. The positive predictive value was 83.5% (95% CI: 81.4-85.6%) and negative predictive value was 89.8% (95% CI: 88.8-90.6%). The kappa statistic was 0.68 (95% CI: 0.66-0.7).

CONCLUSION

School teachers could effectively screen younger school children for vision assessment and ocular disorders.

Amblyopia Prevention Screening Program in Northwest Iran (Ardabil)

BACKGROUND

The aim of this study was to evaluate the results of amblyopia screening in Ardabil Province in three examination levels by kindergarten teacher, optometrist, and ophthalmologist.

METHODS

In a cross-sectional study, the results of the national amblyopic prevention program in 2-6 years old children in Ardabil Province were investigated in 2012. The results pertained to the examinations of children participating in this research were collected in the national approved forms. The data were entered into the computer and were analyzed using statistical methods in SPSS 18.

RESULTS

Around 38,844 children (51.7%) out of 75173 with 2-6 years old qualified children participated in the screening program in Ardabil Province. In the first stage of screening, 1068 children (33.1%) are visually impaired in one eye and 2160 children (66.9%) are visually impaired in two eyes. In the second stage, the results related to the examinations by optometrists indicated that the prevalence of refractive errors, strabismus, and others were 70%, 27.8%, and 2.2%, respectively. Refractive errors problem was most prevalent in Ardabil city (72.6%).The prevalence of refractive errors, strabismus, and other reasons in amblyopic children was 51.3%, 23.9%, and 24.8%; respectively.

CONCLUSIONS

The present investigation showed that coverage of amblyopia screening program was not enough in Ardabil Province. To increase the screening accuracy, standard instruments and examination room must be used; more optometrists must be involved in this program and increasing the validity of obtained results for future programming.

Prevalence and causes of reduced visual acuity among children aged three to six years in a metropolis in China

PURPOSE

To determine the prevalence and possible causes for reduced visual acuity (VA) in preschool children in a metropolis in China.

METHODS

A school-based paediatric eye survey including 5862 preschool children aged three to 6 years was conducted from 2011 to 2012 in Yuhuatai District, Nanjing, China, using an age-stratified random sampling procedure. Clinical examinations including ocular alignment, ocular motility, visual acuity, prism cover test, cycloplegic refraction, stereopsis screening, slit lamp examination and fundus examination were performed by trained study ophthalmologists and optometrists. Reduced VA was defined as presenting VA of worse than 0.30 logMAR (Snellen 6/12 or 20/40), for both better and worse eyes.

RESULTS

5667 (94.8%) children with complete VA data were included in the data analyses. Among them, 208 and 93 had reduced VA in the worse and better eye, respectively. Reduced VA was detected in 3.7% (95% confidence interval [CI] 3.2%-4.2%) in the worse eye and 1.6% (95% CI 1.3%-2.0%) in the better eye. No significant age and gender differences in reduced VA were observed (p > 0.05). Refractive errors and amblyopia were the principal causes for reduced VA in the worse eye which accounted for 66.8% and 32.7% of the total cases with reduced VA, respectively. Astigmatism and hyperopia were the major types of refractive errors causing reduced VA.

CONCLUSIONS

The burden of reduced VA in preschool children in China was similar to that of Asian children of similar ages in the United States. Uncorrected refractive error and amblyopia were the principal causes for reduced VA among preschoolers (aged three to 6 years) in China.

Subjective versus objective accommodative amplitude: preschool to presbyopia

PURPOSE

This study compared subjective and objective accommodative amplitudes to characterize changes from preschool to presbyopia.

METHODS

Monocular accommodative amplitude was measured with three techniques in random order (subjective push-up, objective minus lens stimulated, and objective proximal stimulated) on 236 subjects aged 3 to 64 years using a 1.5-mm letter. Subjective push-up amplitudes were the dioptric distance at which the target first blurred along a near-point rod. Objective minus lens stimulated amplitudes were the greatest accommodative response obtained by Grand Seiko autorefraction as subjects viewed the stimulus at 33 cm through increasing minus lens powers. Objective proximal stimulated amplitudes were the greatest accommodative response obtained by Grand Seiko autorefraction as subjects viewed the stimulus at increasing proximity from 40 cm up to 3.33 cm.

RESULTS

In comparison with subjective push-up amplitudes, objective amplitudes were lower at all ages, with the most dramatic difference occurring in the 3- to 5-year group (subjective push-up, 16.00 ± 4.98 diopters [D] vs. objective proximal stimulated, 7.94 ± 2.37 D, and objective lens stimulated, 6.20 ± 1.99 D). Objective proximal and lens stimulated amplitudes were largest in the 6- to 10-year group (8.81 ± 1.24 D and 8.05 ± 1.82 D, respectively) and gradually decreased until the fourth decade of life when a rapid decline to presbyopia occurred. There was a significant linear relationship between objective techniques (y = 0.74 + 0.96x, R2 = 0.85, p < 0.001) with greater amplitudes measured for the proximal stimulated technique (mean difference, 0.55 D).

CONCLUSIONS

Objective measurements of accommodation demonstrate that accommodative amplitude is substantially less than that measured by the subjective push-up technique, particularly in young children. These findings have important clinical implications for the management of uncorrected hyperopia.

Contrasting effects of strabismic amblyopia on metabolic activity in superficial and deep layers of striate cortex

To probe the mechanism of visual suppression, we have raised macaques with strabismus by disinserting the medial rectus muscle in each eye at 1 mo of age. Typically, this operation produces a comitant, alternating exotropia with normal acuity in each eye. Here we describe an unusual occurrence: the development of severe amblyopia in one eye of a monkey after induction of exotropia. Shortly after surgery, the animal demonstrated a strong fixation preference for the left eye, with apparent suppression of the right eye. Later, behavioral testing showed inability to track or to saccade to targets with the right eye. With the left eye occluded, the animal demonstrated no visually guided behavior. Optokinetic nystagmus was absent in the right eye. Metabolic activity in striate cortex was assessed by processing the tissue for cytochrome oxidase (CO). Amblyopia caused loss of CO in one eye's rows of patches, presumably those serving the blind eye. Layers 4A and 4B showed columns of reduced CO, in register with pale rows of patches in layer 2/3. Layers 4C, 5, and 6 also showed columns of CO activity, but remarkably, comparison with more superficial layers showed a reversal in contrast. In other words, pale CO staining in layers 2/3, 4A, and 4B was aligned with dark CO staining in layers 4C, 5, and 6. No experimental intervention or deprivation paradigm has been reported previously to produce opposite effects on metabolic activity in layers 2/3, 4A, and 4B vs. layers 4C, 5, and 6 within a given eye's columns.

A 1-Year Review of Amblyopia and Strabismus Research

PURPOSE

This current review highlights some of the literature published in the past year from April 2013 to May 2014.

DESIGN

Literature Review.

METHODS

The present review is based on an extended search for pertinent articles on amblyopia and strabismus published during the specified period.

RESULTS

Many articles are often not very comparable to one another because of a lack of randomized clinical trials with most of the studies being retrospective in nature. There is often disagreement on some terminology. Typically, the definition of binocular vision is rarely related to the tests used for evaluating it.

CONCLUSIONS

The authors conclude that adult strabismus patients seem to gain benefits from corrective surgery not only for their ocular misalignment, but also for social anxiety levels that may be associated with improvements in their quality of life and disability levels.