Screening for amblyogenic factors using a volunteer lay network and the MTI photoscreener. Initial results from 15,000 preschool children in a statewide effort

Unveiling Visual Acuity in 58,712 Four-Year-Olds: Standardized Assessment Defined Normative Visual Acuity Threshold

The purpose was to define the threshold of normal visual acuity (VA), mean monocular and binocular VA, and interocular difference in the uniform cohort of healthy four-year-old children. All the children were recruited from the Croatian National Registry of Early Amblyopia Detection database. LEA Symbols® inline optotypes were used for VA testing at near and distance, binocularly and monocularly. The pass cut-off level was set to ≤0.1 logMAR. The final sample consisted of 58,712 four-year-old children. In total, 83.78% of the children had unremarkable results, and 16.22% of the children were referred to examination. Of those, 92% of the children were referred due to binocular, and 8% of the children due to monocular causes. The children referred due to binocular causes demonstrated a VA of 0.3 ± 0.24, while the children referred due to monocular causes 0.6 ± 0.21. The ROC curve analysis defined the uniform cut-off value for a normative VA of 0.78. We analyzed the largest uniform cohort of 58,712 children, and have determined normative data for binocular and monocular VA tested with gold standard logMAR chart in four-year-old children. The results presented here established no reasoning to further utilize historical protocols in testing VA in preschool children aged ≥ 4 years.

Prevalence of Visual Disorders among Urban Palestinian Preschool Children

Background:

Childhood blindness is a major public health concern since 40% of visual disorders that can cause blindness among children are preventable. Vision screening programs among preschool children have been implemented in several countries as a tool for early detection and intervention of visual disorders. In Palestine, there is a lack of scientific data on the prevalence of visual disorders among children. In addition, vision-screening programs that are currently implemented are neither validated nor effective.

Objective:

Using validated vision screening protocols, a cross-sectional study is conducted to determine the prevalence of visual disorders among urban Palestinian preschool children between the ages of 3 to 5 years in Nablus city.

Methods:

All children attending eight preschools selected using single-stage cluster sampling technique, underwent a validated vision screening administered by trained eye care professionals. The screening protocol was based on a combination of clinical assessment adopted from the Modified Clinical Technique and the Vision in Preschoolers studies, including assessment of visual acuity, ocular alignment, depth perception, color vision, non-cycloplegic retinoscopy, and ocular health. A pass-fail criterion was used to refer all children who did not attend the vision screening for comprehensive eye examination, including cycloplegic retinoscopy and a dilated fundus exam. A chi-squared test was used to determine any association between visual disorders and their independent risk factors.

Results:

A total number of 764 children underwent vision screening. Out of the 290 children who did not attend the vision screening, 127 children responded to the referral call for comprehensive eye examinations. Refractive error was the most prevalent visual disorder with a prevalence of (29.37%), followed by amblyopia (4.10%), color vision deficiency (1.24%), strabismus (1.24%), and ocular health abnormalities (0.70%). There was no age (p=0.35) and gender (p=0.32) variation in children having refractive errors. Anisometropia was the leading cause for amblyopia (1.32%, n=7), followed by significant refractive error (1.13%, n=6) and strabismus (0.37%, n=2).

Conclusion:

Refractive error was the most prevalent visual disorder affecting Palestinian preschoolers in Nablus. Anisometropia and significant refractive errors were found to be the major causes of amblyopia. Effective nationwide preschool vision screening programs should be implemented in Palestine to screen amblyogenic risk factors.

Community based vision screening in preschool children; performance of the Spot Vision Screener and optotype testing

BACKGROUND

Children's vision screening children commonly uses optotype-based visual acuity or instrument-based methods measuring amblyogenic risk factors (ARFs).

OBJECTIVE

To compare the performance of the Spot Vision Screener (SVS) (PediaVision, Welch Allyn, NY) and a nurse-administered visual acuity screen (NVAS) in identifying ARFs and decreased visual acuity.

METHODS

A prospective, cross-sectional population-based study of preschool children in South-East Queensland, Australia. Eligible participants had both forms of screening by trained community nurses. All children with an abnormal result by either method as well as a cohort of randomly selected children who passed both assessments were assessed at a tertiary paediatric ophthalmology clinic.

RESULTS

Over a 10 month period, 2237 children (mean age; 64.4 ± 4.0 months) were screened from 38 schools. 6.4% of children failed SVS and 8.3% failed NVAS (with 3.8% overlap, failing both). The positive predictive value (PPV) in identifying either ARFs and/or reduced VA for the SVS and NVAS was 70.4% (95% Confidence Interval (CI): 61.6%-78.2%) and 60.5% (95% CI: 52.6%-67.9%) respectively. Highest PPV to detect either ARFs and/or reduced VA was achieved by a 'hybrid' method by combining failed NVAS and failed SVS: 91.0% (95% CI: 82.4 to 96.3) but this would risk children with sight impairment being missed in the community.

CONCLUSION

To our knowledge, this is the first population-based study providing detailed comparative measures of diagnostic accuracy for NVAS and SVS in preschool children. One in ten preschool children failed one or both screens. A number of children who required ophthalmic intervention were missed if only one screening method was utilized.

Scope and costs of autorefraction and photoscreening for childhood amblyopia-a systematic narrative review in relation to the EUSCREEN project data

Background

Amblyopia screening can target reduced visual acuity (VA), its refractive risk factors, or both. VA testing is imprecise under 4 years of age, so automated risk-factor photoscreening appears an attractive option. This review considers photoscreening used in community services, focusing on costs, cost-effectiveness and scope of use, compared with EUSCREEN project Country Reports describing how photo- and automated screening is used internationally.

Methods

A systematic narrative review was carried out of all English language photoscreening literature to September 10th 2018, using publicly available search terms. Where costs were considered, a CASP economic evaluation checklist was used to assess data quality.

Results

Of 370 abstracts reviewed, 55 reported large-scale community photoscreening projects. Five addressed cost-effectiveness specifically, without original data. Photoscreening was a stand-alone, single, test event in 71% of projects. In contrast, 25 of 45 EUSCREEN Country Reports showed that if adopted, photoscreening often supplements other tests in established programmes and is rarely used as a stand-alone test. Reported costs varied widely and evidence of cost-effectiveness was sparse in the literature, or in international practice. Only eight (13%) papers compared the diagnostic accuracy or cost-effectiveness of photoscreening and VA testing, and when they did, cost-effectiveness of photoscreening compared unfavourably.

Discussion

Evidence that photoscreening reduces amblyopia or strabismus prevalence or improves overall outcomes is weak, as is evidence of cost-effectiveness, compared to later VA screening. Currently, the most cost-effective option seems to be a later, expert VA screening with the opportunity for a re-test before referral.

Utilizing minicomputer technology for low-cost photorefraction: a feasibility study

Eccentric photorefraction is an objective technique to determine the refractive errors of the eye. To address the rise in prevalence of visual impairment, especially in rural areas, a minicomputer-based low-cost infrared photorefractor was developed using off-the-shelf hardware components. Clinical validation revealed that the developed infrared photorefractor demonstrated a linear working range between +4.0 D and -6.0 D at 50 cm. Further, measurement of astigmatism from human eye showed absolute error for cylinder of 0.3 D and high correlation for axis assessment. To conclude, feasibility was shown for a low-cost, portable and low-power driven stand-alone device to objectively determine refractive errors, showing potential for screening applications. The developed photorefractor creates a new avenue for telemedicine for ophthalmic measurements.

Identifying barriers to referrals in preschool-age ocular screening in Southern India

Purpose:

The aim of this study was to identify barriers to follow-up among children aged 0–5 years who failed ocular screening.

Methods:

A cross-sectional, descriptive study was conducted for screening children aged 0–5 years, covering three districts of South India from January 2012 to December 2012. Screening was performed under Lavelle Paediatric Eye Care Project, included under Integrated Child Development Services (ICDS) program. A survey was conducted within 60 days of the screening, with the parents of children who failed to follow up at base hospital. Family demographics, parental awareness of childhood eye diseases and eye care for children, and barriers to follow up eye care were assessed.

Results:

A total of 19,408 children were screened. Among them, 913 (4.7%) failed screening and were referred. 319 (35%) of those referred attended the base hospital, of which 133 (41.6%) had no abnormality on detailed examination. 111 (34.7%) had refractive errors, 10 (3%)) had strabismus, and three (1%) had amblyopia. 62 (19.4%) had other ocular conditions. Parents of 324/594 (65%) children who did not attend the base hospital were traced and completed the questionnaire. Low level of education, low income, types of occupation, and distance factors were the main barriers to follow-up of referral in preschool children. Factors such as cost of time taking off from work and monthly family income were statistically significant (P < 0.001).

Conclusion:

Education, financial status, and distance factors were the main barriers to follow up of referral in preschool children. Identification of these barriers to follow up and improving the referral services could help in detecting visual problem effectively.

Successes and shortfalls of community Plusoptix photoscreening: results from the iSee study in Southwestern Ontario

OBJECTIVE

The purpose of this work is to provide the final results from a community-wide photoscreening program in Southwestern Ontario for children aged 18 to 72 months, and to estimate the prevalence of amblyogenic risk factors in this population.

STUDY DESIGN

Prospective, multisite photoscreening program.

PARTICIPANTS

5959 children aged 18-72 months were recruited and screened in Southwestern Ontario at 210 locations over a period of 3 years and 4 months.

METHODS

Ophthalmic screening examinations were performed with the Plusoptix S12 photoscreener. The threshold for the referral criteria used was the manufacturer's criteria on receiver operating characteristics 4.

RESULTS

The screening was negative in 5386 children (90.4%), positive in 403 (6.8%), and unreadable in 170 (2.9%); 42% of all screened children were ≤36 months old. The estimated amblyogenic risk factor prevalence of anisometropia was 4.0%, astigmatism was 3.1%, hyperopia was 1.1%, myopia was 0.4%, and strabismus was 0.4%. Of the 403 referred children, 99 (24.5%) completed a formal eye examination based on the responses returned to the study site.

CONCLUSIONS

This is the first Canadian study that provides data on amblyogenic risk factors based on a volunteer-led photoscreening program. Photoscreening is an effective screening tool, particularly for pre-school-aged children; however, the lack of mandatory follow-up to ensure that children receive proper treatment based on cycloplegic refraction reduces the efficacy of screening.

A community-based effort to increase the rate of follow-up eye examinations of school-age children who fail vision screening: a randomized clinical trial

PURPOSE

To determine whether enhanced follow-up after failed vision screening, involving more communication with parents/guardians than occurs in a standard protocol, would result in a higher rate of post-screening examination by an eye care provider.

METHODS

In a study conducted from January through December 2017, 162 children in first- and third-grade who failed a vision screening in their Wayne County, Michigan, schools were randomly assigned to receive an enhanced or the standard follow-up protocol.

RESULTS

The average age of the children was 7.9 ± 1.1years; 84 (52%) were males. In the enhanced follow-up group, 52 of 80 (65%) had a documented eye examination within 16 weeks of their screening; the rate in those receiving standard follow-up was 48% (39/82). The intergroup difference in follow-up was 17.4% (95% CI, 2.4%-32.5%). The enhanced follow-up group's odds of obtaining a documented eye examination was twice that of the standard follow-up group (OR = 2.05; 95% CI, 1.09-3.85; P = 0.026).

CONCLUSIONS

In this study cohort, methods to enhance communication proved effective in increasing the likelihood that children who failed vision screenings would receive an examination by an eye care provider.

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.

Photoscreening for amblyogenic risk factors in 1-year-olds: results from a single center in Portugal over a 9-year period

PURPOSE

To report the experience of a single center in photoscreening 1-year-olds for amblyogenic risk factors over a 9-year period and to estimate amblyopia prevalence in this population.

METHODS

The records of 11,029 children 11-18 months of age who were screened for amblyogenic risk factors at Centro Hospitalar de Entre o Douro e Vouga between 2004 and 2012 were reviewed. Measurements were performed with MTI (until 2008) and plusoptiX S04 (from 2009). The screening results were evaluated according to criteria adapted from Donahue and colleagues.

RESULTS

The screening was negative in 8,985 children (82%), positive in 519 (5%), unreadable in 201 (2%), and borderline in 1,324 (12%). The overall positive predictive value (PPV) for the presence of at least one amblyogenic risk factor was 56.8%. The estimated prevalence of meaningful refractive errors in this population was 2.2%; of strabismus, 0.3%.

CONCLUSIONS

The rate of unreadable screenings was low. The overall PPV was lower than other large studies, at older ages, but higher than those of the same-age children. Considering the potential benefits of early intervention in preventing the development of amblyopia, this study demonstrates the feasibility of screening 1-year-olds.

The Use of a Mobile Van for School Vision Screening: Results of 63 841 Evaluations

PURPOSE

To present data from an established mobile screening program for children in the amblyogenic age group using gold-standard examination techniques by eye care professionals.

DESIGN

Retrospective 12-year, cross-sectional study.

METHODS

setting: Single center.

STUDY POPULATION

All children enrolled in pre-kindergarten, kindergarten, and first grades in public schools in Cleveland, Ohio were eligible for evaluations. intervention procedure: An ophthalmic technician and/or optometrist examined children in a customized van that visits all elementary schools. The initial screening included testing of monocular near and distance visual acuity, stereoacuity, ocular alignment, motility, pupils, and external abnormalities. Children meeting the 2003 American Academy of Pediatrics vision screening referral criteria underwent cycloplegic retinoscopy and ophthalmoscopy by the on-site optometrist and received glasses. In addition, these children were referred to pediatric ophthalmology for ongoing care.

MAIN OUTCOME MEASURE

Determination of the proportion of children with refractive errors, amblyopia, and/or strabismus.

RESULTS

Between 2002 and 2014, 63 841 evaluations were performed, representing approximately 55% of eligible children. Overall, 6386 (10.0%) of children met 1 or more referral criteria: 5355 (8.39%) received glasses, 873 (1.37%) had amblyopia, and 1125 (1.76%) had strabismus. Over the 12-year period, there was no statistically significant change in the prevalence of strabismus (1.73%-2.24%, P = .91) or amblyopia (0.9%-2.08%, P = .13) among first grade students.

CONCLUSIONS

Amblyopia, strabismus, and refractive errors are common in young children. During the study period, the rates of amblyopia and strabismus remained stable, indicating the need for continued vision screening and treatment services. A van-based model, traveling directly to schools, appears to be effective in reaching young children in underserved communities.

The W.H.E.E.L.S. Preschool Vision Screening Program's Initial Outcomes for 12,402 Children Screened Using the Plusoptix Photoscreener

Objective. To report the results of the W.H.E.E.L.S. Prevent Blindness Mid-Atlantic vision screening program that targets preschoolers using the Plusoptix Photoscreener (Plusoptix Inc., Nuremburg, Germany). Methods. Trained program staff members conducted vision screenings at up to 113 preschool programs in the Richmond metropolitan area for four consecutive years; a cross-sectional analysis was performed. Results and Discussion. From September 2010 to March 2014, 15,075 preschoolers have been offered a free vision screening; 12,402 (82%) have been screened. A total of 3,018 (24%) have failed the screening and were recommended to follow up with an eye care specialist for a comprehensive examination; only 30% reported complying. Significant refractive errors were more frequently the cause for a failed screening. Conclusions. The W.H.E.E.L.S. program has identified a high number of preschoolers with significant amblyopic risk factors that were previously unknown to be present. Undesirably low follow-up reporting outcomes from children who fail a vision screening examination were consistent with other reports. Nevertheless, having a mobile vision screening program that uses photoscreening technology in targeting children prior to school entry is an efficient and cost-effective way to detect vision disorders in a timely manner.

Preschool vision screening: update on guidelines and techniques

PURPOSE OF REVIEW

To discuss the current preschool vision screening (PVS) guidelines and review some of the newest vision screening techniques. The different vision screening practices and barriers to screening are discussed.

RECENT FINDINGS

Vision screening guidelines, which have been developed in response to the advances in technology and increased understanding of the developing visual system, have been recently updated by some of the major medical organizations that endorse vision screening. With advances in vision screening technology, there is a growing trend for screening at younger ages.

SUMMARY

PVS has been widely endorsed by various medical organizations as an effective way to detect preventable and treatable vision problems of childhood. Although PVS is widely recommended, actual screening rates remain low. There are several real and perceived barriers to screening which often prevents successful screening programs. Current vision screening guidelines take into account the recent advances in technology. With the development of new devices, vision screening can effectively be performed at younger ages.

Results of a community vision-screening program using the Spot photoscreener

PURPOSE

To describe the results of vision screenings performed with the Spot photoscreener in the community setting.

METHODS

Low-income, predominantly Hispanic children in day care and preschool settings were screened by lay operators using the Spot photoscreener. Inclusion criteria were age 6-72 months and availability of a complete photoscreening record. Referral criteria were based on Vision Screening Committee of American Association for Pediatric Ophthalmology and Strabismus guidelines. Data were stratified by age group and analyzed for percentage of children referred for hyperopia, myopia, astigmatism, anisometropia, anisocoria, and ocular misalignment. Vision screening records were compared with comprehensive eye examination records from an optometrist or ophthalmologist to determine positive predictive value.

RESULTS

Vision screening examinations were performed on 8,317 subjects from September 2011 through May 2012. The mean age of the 7,814 subjects (3953 males) meeting inclusion criteria was 44.4 months. The Spot referred 2,393 (30.6%). Of the screened population, the suspected reason for referral was astigmatism in 1,863 (23.8%), ocular misalignment in 879 (11.3%), anisometropia in 90 (1.2%), myopia in 82 (1.1%), hyperopia in 63 (0.8%), and anisocoria in 16 (0.2%). Comprehensive examination reports, including a cycloplegic refraction, were available for 300 referred children (12.5%). The reason for referral was confirmed in 55.7%, with an overall positive predictive value of 65.7%.

CONCLUSIONS

The Spot photoscreener yielded a high overall referral rate. Although a high prevalence of astigmatism may be expected in this population, a high referral rate for suspected ocular misalignment led to a very high proportion of false positive referrals, suggesting that the software for this algorithm is in need of refinement.

Identifying barriers to follow-up eye care for children after failed vision screening in a primary care setting

PURPOSE

To identify barriers to follow-up eye care in children who failed a visual acuity screening conducted by their primary care provider.

METHODS

Children aged 3-14 years who failed a visual acuity screening were identified. A phone survey with the parent of every child was conducted 4 months after the screening. Family demographics, parental awareness of childhood eye diseases and eye care for children, and barriers to follow-up eye care were assessed.

RESULTS

Of 971 children sampled, 199 (20.5%) failed a visual acuity screening. The survey was completed by the parents of 58 children (29.1%), of whom 27 (46.6%) presented for follow-up examination. The most common reason for failure to follow-up was parental unawareness of screening results (29.3%). Follow-up rates were higher in children with previous eye examinations than in those without (81% versus 17%; P = 0.005) and in children who waited <2 months for a follow-up appointment than in those who had to wait longer (100% versus 63%; P = 0.024). Child's sex, ethnicity, and health insurance status, parent's marital, education and employment status, household income, and transportation access were not associated with statistically significant different follow-up rates.

CONCLUSIONS

Parental unawareness of a failed visual acuity screening is an important barrier to obtaining follow-up. Strategies to improve follow-up rates after a failed visual acuity screening may include communicating the results clearly and consistently, providing education about the importance of timely follow-up, and offering logistic support for accessing eye appointments to families.

Unmet eye care needs among U.S. 5th-grade students

BACKGROUND

There is substantial evidence of a disparity in access to eye care services among adults in the U.S.; however, little is known about health disparities for children's eye care.

PURPOSE

The goal of the study was to assess the prevalence of and risk factors for 5th-grade students' unmet eye care needs.

METHODS

Data were collected from 5147 5th-grade students (aged 10-11 years) and their parents and primary caregivers (hereafter "parents") participating in the Healthy Passages study between fall 2004 and summer 2006 (analyzed in 2011). Logistic regression estimated the probability of inability to afford needed eyeglasses and absence of vision insurance coverage.

RESULTS

1794 5th-grade students wore eyeglasses or were told that they need eyeglasses; 13.7% of their parents were unable to afford needed eyeglasses (new prescription or replacement) for their children; 27.4% of their parents reported no vision insurance coverage for eye examinations and eyeglasses. After controlling for confounders, parents without general children's health insurance were more likely to report being unable to afford eyeglasses than those with health insurance (Medicaid, SCHIP, private/other insurance; adjusted percentages: 22.5% vs 10.9%, 9.6%, 12.5%; all p<0.05). Parents with lower income were more likely to report being unable to afford children's eyeglasses even after controlling for all other factors (17.6% with income <$15,000 vs 2.7% with income ≥$70,000; p<0.001).

CONCLUSIONS

SES and health insurance status are strongly associated with 5th-grade students' unmet eye care needs. Policies targeting socioeconomically disadvantaged groups and those without insurance may be needed to reduce disparities in access to appropriate eye care.

Retinoblastoma in a child after normal autorefraction and traditional vision screening

Retinoblastoma is an ocular malignancy that can put a patient's sight and, in some instances, life at risk. Here we report the case of a 2-year-old child who presented to her pediatrician with a 2-week history of left-sided leukocoria caused by retinoblastoma. Results of traditional office-based vision screening and automated vision screening, which often identify but are not specifically designed to detect rare diseases such as retinoblastoma, had been normal in the antecedent 7 months. She underwent enucleation of the left eye and has done well postoperatively. This case highlights the importance of assessing ocular media clarity by using red-reflex testing at multiple intervals during the preschool years, particularly in light of the recently published US Preventive Services Task Force guidelines for preschool vision screening, which gave an "insufficient evidence" level for vision screening in children younger than 3 years and failed to address red-reflex examination.

Vision and the achievement gap among urban minority youth

OBJECTIVES

To outline the prevalence and disparities of vision problems among school-aged urban minority youth, causal pathways through which vision problems adversely affects academic achievement, and proven or promising approaches for schools to address these problems.

METHODS

Literature review.

RESULTS

More than 20% of school-aged youth have some kind of vision problem. In a nationally representative sample of more than 48,000 youth under age 18, those from lower income families were less likely to have diagnosed eye conditions than White children and children living in higher income families. When diagnosed with eye care problems, Black youth living in poverty received fewer and less intensive services. Causal pathways through which vision problems adversely affect academic achievement include sensory perceptions, cognition, and school connectedness. Vision screening is widespread in the nation's schools, but the educational (and public health) benefits from these efforts are jeopardized by lack of follow-up and coordination of efforts.

CONCLUSIONS

Vision problems are highly and disproportionately prevalent among school-aged urban minority youth, have a negative impact on academic achievement through their effects on sensory perceptions, cognition, and school connectedness, and effective practices are available for schools to address these problems. School-based vision screening programs are a logical approach for the early detection and treatment of vision problems affecting youth and are widely implemented in the nation's schools. To more fully realize the educational (and public health) benefits of current investments in screening, programs will require improved follow-up and coordination between and among agencies conducting screening, school nurses, teachers and parents, and in some cases community resources.

A review of the evidence on the effectiveness of children's vision screening

Screening programmes enable health conditions to be identified so that effective interventions can be offered. The aim of this review was to determine: (1) the effectiveness of children's vision screening programmes; (2) at what age children should attend vision screening; and (3) what form vision screening programmes should take to be most effective. A literature review on the effectiveness of vision screening programmes in children aged 0-16 years was undertaken. Eligible studies/reviews were identified through clinical databases, hand searches and consultation with expert reviewers. The methodological quality of papers was rated using National Health and Medical Research Council (NHMRC) guidelines. Screening of children 18 months to 5 years, and subsequent early treatment, led to improved visual outcomes. The benefit was primarily through treatment of amblyopia, with improved visual acuity of the amblyopic eye. However, the overall quality of the evidence was low. The implication of improved visual acuity (e.g. any potential impact on quality of life) was not considered. Without consideration of 'quality of life' values, such as loss of vision in one eye or possibility of future bilateral vision loss, the cost-effectiveness of screening is questionable. Screening and treating children with uncorrected refractive error can improve educational outcomes. Evidence suggested that screening occur in the preschool years. Orthoptists were favoured as screening personnel; however, nurses could achieve high sensitivity and specificity with appropriate training. Further research is required to assess the effectiveness of neonatal screening. Most studies suggested that children's vision screening was beneficial, although programme components varied widely (e.g. tests used, screening personnel and age at testing). Research is required to clearly define any improvements to quality of life and any related economic benefits resulting from childhood vision screening. The evidence could be used to guide optimization of existing programmes.

Longitudinal follow-up of hypermetropic children identified during preschool vision screening

PURPOSE

Early childhood hypermetropia is an important risk factor for the development of amblyopia and esotropia. Understanding the natural history of these complications aids in management decisions.

METHODS

A retrospective observational review was undertaken of 149 patients referred from a preschool photoscreening program who were determined to have hypermetropia of >or=+3.75 D spherical equivalent on criterion standard examination and were treated/followed by one group of academic pediatric ophthalmologists. The prevalence and incidence of accommodative esotropia and amblyopia were determined.

RESULTS

At presentation 19% of hypermetropic children had amblyopia, 32% had esotropia, and 13% had both. Follow-up data of 108 patients during a mean of 40 months showed that 20 (24%) of 83 initially nonamblyopic patients developed amblyopia and that 22 (33%) of 67 initially nonstrabismic patients developed accommodative esotropia. Of patients initially managed with observation, 38% (6 of 16) developed amblyopia, and 31% (5 of 16) developed accommodative esotropia as compared with 21% (14 of 67) and 33% (17 of 51), respectively, for those given full or partial refractive correction. For patients without amblyopia or strabismus at presentation, only 20% developed amblyopia and 35% esotropia. Strabismic patients responded well to treatment, with no cases developing partially accommodative strabismus requiring surgery during follow-up.

CONCLUSIONS

In this case series we found a high prevalence of amblyopia and strabismus. The results support the importance of early preschool vision screening and spectacle correction of moderate to high hypermetropia (>+3.50 D) to reduce the risk of amblyopia, although more research is needed.

Receding and disparity cues aid relaxation of accommodation

PURPOSE

Accommodation can mask hyperopia and reduce the accuracy of non-cycloplegic refraction. It is, therefore, important to minimize accommodation to obtain a measure of hyperopia as accurate as possible. To characterize the parameters required to measure the maximally hyperopic error using photorefraction, we used different target types and distances to determine which target was most likely to maximally relax accommodation and thus more accurately detect hyperopia in an individual.

METHODS

A PlusoptiX SO4 infra-red photorefractor was mounted in a remote haploscope which presented the targets. All participants were tested with targets at four fixation distances between 0.3 and 2 m containing all combinations of blur, disparity, and proximity/looming cues. Thirty-eight infants (6 to 44 weeks) were studied longitudinally, and 104 children [4 to 15 years (mean 6.4)] and 85 adults, with a range of refractive errors and binocular vision status, were tested once. Cycloplegic refraction data were available for a sub-set of 59 participants spread across the age range.

RESULTS

The maximally hyperopic refraction (MHR) found at any time in the session was most frequently found when fixating the most distant targets and those containing disparity and dynamic proximity/looming cues. Presence or absence of blur was less significant, and targets in which only single cues to depth were present were also less likely to produce MHR. MHR correlated closely with cycloplegic refraction (r = 0.93, mean difference 0.07 D, p = n.s., 95% confidence interval +/-<0.25 D) after correction by a calibration factor.

CONCLUSIONS

Maximum relaxation of accommodation occurred for binocular targets receding into the distance. Proximal and disparity cues aid relaxation of accommodation to a greater extent than blur, and thus non-cycloplegic refraction targets should incorporate these cues. This is especially important in screening contexts with a brief opportunity to test for significant hyperopia. MHR in our laboratory was found to be a reliable estimation of cycloplegic refraction.

The value of serial personal photographs in timing the onset of unilateral cataracts in children

PURPOSE

To determine the value of serial personal photographs in timing the onset of unilateral cataracts in children over 6 months of age.

METHODS

Personal photographs from children with unilateral cataracts who underwent cataract extraction and intraocular lens implantation when > or =6 months of age were reviewed. Photographs were evaluated for changes in the red reflex, which might indicate the presence of a cataract.

RESULTS

Twelve children underwent cataract surgery at a mean age of 37 months. They were followed for a mean of 32 months. Ten children were diagnosed as having an acquired cataract by photographic review documenting a previously normal red reflex. The visual acuity in the affected eye of 4 of these children improved to > or =20/60. Cataracts were visible on photographs prior to clinical diagnosis in 6 patients, from 0.5 to 22 months prior to clinical diagnosis. Visual outcomes did not relate closely to the photographically documented duration of the cataract prior to treatment. Photographs were not helpful in timing the onset of cataract in 2 children due to the poor quality of the images.

CONCLUSIONS

Serial personal photographs are sometimes helpful in determining whether cataracts are acquired. However, the usefulness of personal photographs alone in predicting the visual outcome after cataract surgery was limited in this small, retrospective study.

Photo screening around the world: Lions Club International Foundation experience

PURPOSE

To describe the use of photoscreening for preschool vision screening in several diverse locations throughout the world.

METHODS

The MTI photo screener was used to screen pre-verbal children; photographs were interpreted using standard criteria.

RESULTS

The Tennessee vision screening program remains successful, screening over 200,000 children during the past 8 years. Similar programs modeled across the United States have screened an additional 500,000 children. A pilot demonstration project in Hong Kong, Beijing, and Brazil screened over 5000 additional children with good success and appropriately low referral rates.

CONCLUSION

Photoscreening can be an appropriate technique for widespread vision screening of preschool children throughout the world.

Field testing of the plusoptiX S04 photoscreener

PURPOSE

To evaluate the diagnostic accuracy of the plusoptiX S04 digital photoscreener in a school screening program.

METHODS

Between 2006 and 2007, 1343 information pamphlets/consent forms were sent to all junior kindergarten students in a local school district. Assistants from a local public health unit photographed 307 children. Of these, 271 children received an independent ophthalmic examination by a physician. Photographic results were compared with the those of the ophthalmic examination. Amblyopia risk factors were defined as anisometropia >1 D (sphere or cylinder), astigmatism >1.25 D, myopia >3 D, hyperopia >3.5 D, any manifest strabismus, and any media opacity.

RESULTS

Photographic and examination results agreed in 94% of cases. Sensitivity in detecting amblyopia risk factors was 83%; specificity was 95%. The positive and negative predictive values were 73% and 97%, respectively. The untestable/unusable rate was 1%.

CONCLUSIONS

These results compare favorably with a previously reported (but no longer available) digital photoscreening camera and are superior to results obtained with other off-axis photoscreening devices that require human interpretation. On the basis of these results, in a real-world screening program, the camera would falsely refer 4% of those screened and would fail to correctly refer 2%. The accuracy of the plusoptiX S04 camera in detecting amblyopia risk factors appears sufficiently high to consider its further deployment in a widespread school screening program.

The age-dependent effect of anisometropia magnitude on anisometropic amblyopia severity

INTRODUCTION

Anisometropia is an important cause of amblyopia. The relationship between anisometropia depth and amblyopia magnitude is not well characterized, as previous studies have been limited to patients identified because of their amblyopia. We analyzed results from anisometropic patients identified with photoscreening to eliminate this selection bias.

METHODS

We performed a retrospective observational study of preschool children with anisometropia >1.0 D identified during a statewide photoscreening program. Nine hundred seventy-four children with anisometropia were detected over a 9-year period. Visual acuity, cycloplegic refraction data, and patient age from a formal follow-up examination were analyzed. Effect of anisometropia magnitude on amblyopia was measured by ordinal logistic regression, taking age into account.

RESULTS

Six hundred forty (65.7%) children had amblyopia > or =2 lines. Three hundred sixty-four (37.4%) had > or =4 lines amblyopia. There was a statistically significant increase in risk of amblyopia with increasing magnitude of anisometropia. Calculated odds ratios for amblyopia with maximal meridional anisometropia of > or =2 to <4 D compared with >1 to <2 D was 2.13 (95% CI [1.63, 2.78], p < 1 x 10(-7)), and 2.34 (95% CI [1.67, 3.28], p < 1 x 10(-6)) when comparing > or =4 D to > or =2 to <4 D. Odds ratios for spherical equivalent anisometropia were also highly statistically significant.

CONCLUSIONS

Children with higher magnitudes of anisometropia had higher prevalence and greater depth of amblyopia. Older children had an increased risk of amblyopia compared with younger children for moderate levels of anisometropia. Low magnitude anisometropia in young children may not predispose to amblyopia; these findings have implications for vision screening criteria at various ages.

Comparison of the MTI Photoscreener and the Welch-Allyn SureSight autorefractor in a tertiary care center

INTRODUCTION

The MTI photoscreener (MTI) and the Welch-Allyn SureSight autorefractor are commonly used for preschool vision screening. We compared both of these methods on 100 consecutive patients in a prospective, randomized, masked, clinical trial conducted at a tertiary care center.

METHODS

One hundred patients between 1 and 6 years of age were included in the study. All participants underwent a comprehensive eye examination with cycloplegic refraction. Examination failure analysis was done on the SureSight data using the manufacturer's referral criteria, the Vision in Preschoolers study (VIP) 90% specificity criteria, the VIP 94% specificity criteria, and the referral criteria proposed by Rowatt and colleagues.

RESULTS

Data were successfully obtained on 76% of children using the SureSight and 96% with the MTI. The sensitivity and specificity of the SureSight to detect clinically significant amblyogenic factors using the manufacturer's criteria was 96.6 and 38.1%, using the VIP 90% criteria was 79.3 and 64.3%, using the VIP 94% criteria was 67.2 and 69.0%, and using criteria proposed by Rowatt and colleagues was 62.1 and 73.8%. The sensitivity and specificity of the MTI photoscreener was 94.8 and 88.1%, respectively.

CONCLUSIONS

Using the manufacturer's referral criteria, the SureSight had a sensitivity equal to the MTI photoscreener; however, the specificity was low and over-referrals were anticipated. As specificity levels were increased, a substantial number of children with amblyogenic risk factors were not appropriately identified within our study population..

A comparison of photorefraction and retinoscopy in children

PURPOSE

To compare the results of photorefraction measurement obtained with a Plusoptix CR03 to those of cycloplegic retinoscopy as a standard refraction method in children.

METHODS

We assessed the refractive status of 204 eyes in 204 healthy children. The values acquired via photorefraction (noncycloplegic refraction) with a Plusoptix CR03 device were compared with those obtained via cycloplegic retinoscopy. Both methods were used in the same eyes and in all children. The paired tt-test and Pearson's correlation analysis were used for statistical analysis.

RESULTS

The mean age was 7.1 +/- 2.4 years (range, 9 months to 14 years). The average spherical refractive error was +0.05 +/- 0.65 D for photorefraction versus +0.75 +/- 0.77 D for cycloplegic retinoscopy (average difference, -0.70 D; p < 0.001), with moderate correlation between measures (r = 0.63). The average cylinder power was +0.43 +/- 0.38 D for photorefraction versus +0.29 +/- 0.38 D for cycloplegic retinoscopy (average difference, +0.14 D; p < 0.001), with moderate correlation between measures (r = 0.70). The average spherical equivalent was +0.26 +/- 0.63 D for photorefraction versus +0.90 +/- 0.76 D for cycloplegic retinoscopy (average difference, -0.64 D; p < 0.001), with moderate correlation between measures (r = 0.63).

CONCLUSIONS

The Plusoptix CR03 device tends toward minus overcorrection in children, resulting in overdiagnosis of myopia. Studies of a population of subjects with a larger range of ametropia will be required to validate this instrument as a screening tool.

Diagnosis and treatment of refractive errors in the pediatric population

PURPOSE OF REVIEW

The diagnosis and successful treatment of visually significant refractive errors in children are a subject of continued study and debate.

RECENT FINDINGS

Treatment of significant refractive errors is widely accepted to reduce lifelong vision loss from amblyopia. Children aged 3-5 years may be screened for unexplained vision loss, refractive errors and amblyogenic factors using traditional eye charts as well as newer modalities such as autorefractors and photoscreeners. The accuracy of various screening methods is variable throughout the literature. Debate remains as to who is best suited to administer vision screening tests. Compliance with follow-up with an eye-care professional once a child is identified with an amblyogenic factor remains suboptimal. Treatment of significant refractive errors in certain populations of pediatric patients with refractive surgery shows promise but requires further study.

SUMMARY

The timely diagnosis of significant refractive errors in children remains a significant challenge, especially for ages 3-5 years, but treatment may provide significant improvement of visual acuity and quality of life.

Comparing the effectiveness of vision screenings as part of the school entrance physical examination to comprehensive vision examinations in children ages 3 to 6: An exploratory study

PURPOSE

The purpose of this exploratory study was to investigate the effectiveness of vision screenings performed during school entrance physical examinations compared with comprehensive vision examinations in the state of Kentucky, which mandates comprehensive eye examinations for children, ages 3 to 6, who are entering the public school system.

METHODS AND SUBJECTS

In this exploratory study, 1,386 children had forms submitted from 36 optometrists and 1 ophthalmologist reporting on their vision and eye problems. Vision and eye problems were defined as the presence of strabismus, amblyopia, or a refractive error requiring an optical correction, as determined by the optometrists or ophthalmologist using cycloplegic refraction. Among these 1,386 children, there were 300 diagnosed with vision problems.

RESULTS

Sixty-six children were diagnosed with a vision problem who had not previously been to an eye doctor and had received a vision screening at their school entrance physical examination. In 56 of these 66 children, the vision problem was not detected by the vision screening, according to the parents.

CONCLUSION

The exploratory study suggests that comprehensive vision examinations may identify some vision problems that were not found in children's preschool physical examinations that included vision screenings. A larger randomized study is needed to determine the most appropriate method of timely diagnosis of vision problems in children that can be corrected with early intervention in order to ensure the vision health and well-being of children entering the public school system.

Barriers to follow-up eye care after preschool vision screening in the primary care setting: findings from a pilot study

Timely follow-up after an abnormal preschool vision screening test is necessary for the prevention of amblyopia. A previous large community-based preschool vision screening program found that only approximately half of those children who were referred were documented to have received follow-up care. No similar data are available regarding follow-up from the primary care setting. We present findings from a pilot study designed to identify barriers to follow-up care faced by families screened by pediatricians and family physicians. These data will be used in larger studies to measure rates of follow-up and to develop interventions to improve the detection of amblyopia and conditions associated with the development of amblyopia.

Relationship between anisometropia, patient age, and the development of amblyopia

PURPOSE

Previous studies evaluating the effect of anisometropia on amblyopia development have been biased because subject selection occurred as a result of decreased acuity. Photoscreening identifies anisometropic children in a manner that is not biased by acuity, and allows an opportunity to evaluate how patient age influences the prevalence and depth of amblyopia.

DESIGN

Retrospective observational study of preschool children with anisometropia.

METHODS

A statewide preschool photoscreening program screened 119,311 children and identified 792 with anisometropia >1.0 diopters. We correlated age with visual acuity and amblyopia depth. Results were compared with 562 strabismic children similarly identified.

RESULTS

Only 14% (six of 44) of anisometropic children aged 1 year or younger had amblyopia. Amblyopia was detected in 40% (32 of 80) of 2-year-olds, 65% (119 of 182) of 3-year-olds, and 76% of 5-year-olds. Amblyopia depth also increased with age. Moderate amblyopia prevalence was 2% (ages 0 to 1), 17% (age 2), and rose steadily to 45% (ages 6 to 7). Severe amblyopia was rare for children aged 0 to 3, 9% at age 4, and 14% at age 5. Children with strabismus had a relatively stable prevalence (30% ages 0 to 2; 42% ages 3 to 4; and 44% ages 5 to 7) and depth of amblyopia.

CONCLUSIONS

Younger children with anisometropia have a lower prevalence and depth of amblyopia than older children. By age 3, when most children undergo traditional screening, amblyopia has usually already developed. New vision screening technologies that allow early detection of anisometropia provide ophthalmologists an opportunity to intervene early, perhaps retarding or even preventing the development of amblyopia.

Validation of the PowerRefractor for measuring human infant refraction

PURPOSE

Eccentric photorefraction provides an opportunity to gather rapid and remote estimates of refraction and gaze position from infants. The technique has the potential for extensive use in vision screenings and studies of visual development. The goal of this study was to assess the refraction calibration of the PowerRefractor (Multichannel Systems) for use with uncyclopleged infants.

METHODS

The defocus measurements from the instrument were compared with the results of simultaneous retinoscopy in one analysis and with known amounts of defocus induced with trial lenses in another. Data were collected from infants 1 to 6 months of age and adults.

RESULTS

The PowerRefractor typically read < 1 D of myopia when the retinoscopy reflex was judged to be neutral at the same working distance in both infants and adults. The slopes of both infant and adult validation functions (trial lens power vs. measurement of induced defocus) were close to 1 over a 4D range. The infant slopes were significantly greater than those of the adults, however.

CONCLUSIONS

The results suggest that the instrument is capable of detecting large amounts of defocus but needs individual calibration for detailed studies of accommodative accuracy and absolute levels of defocus, as has been recommended previously for adult subjects.

Lions Clubs International Foundation Core Four Photoscreening: results from 17 programs and 400,000 preschool children

INTRODUCTION

Photoscreening programs for preschool vision screening have been promoted by Lions Clubs International Foundation (LCIF) via their 17 Core Four grant project awards since 1999. Results from 15 Core Four grant programs in the United States and one in Taiwan are presented here.

METHODS

Photoscreening was modeled after the Tennessee program and instituted statewide in each area. Programs were given latitude with respect to screening instrument and referral criteria, but a partnering academic institution and medical director were expected. Preschool children were screened by volunteers; referred children were examined by community optometrists and ophthalmologists who returned results to each program's coordinating center. Outcome data included number of children screened, referral rate, follow-up rate, and positive predictive value, which was generally determined using AAPOS-defined vision screening criteria.

RESULTS

All but one program used the MTI photoscreener (it chose not to participate); photoscreening referral criteria were standard for 13 programs. Through December 2004, more than 400,000 preschool children had been screened. The referral rate for programs using the MTI photoscreener averaged 5.2% (range, 3.7-12.6%). The predictive value of a positive photoscreen was 80%. Overall, 54% of referred children received follow-up examinations. Follow-up rate was the largest variable: 4 programs, screening nearly 250,000 children, had follow-up rates 70% or greater; 10 programs had follow-up data from fewer than 40% of referred children.

CONCLUSIONS

Volunteer-led photoscreening programs can be instituted in other locations, including overseas, with high levels of effectiveness. Limitations include the possibility of poor success and variable attention to follow-up.

Pediatric Amblyopia Risk Investigation Study (PARIS)

PURPOSE

To assess the learning curve, testability, and reliability of vision screening modalities administered by pediatric health extenders.

DESIGN

Prospective masked clinical trial.

METHODS

Two hundred subjects aged 3 to 6 underwent timed screening for amblyopia by physician extenders, including LEA visual acuity (LEA), stereopsis (RDE), and noncycloplegic autorefraction (NCAR). Patients returned for a comprehensive diagnostic eye examination performed by an ophthalmologist or optometrist.

RESULTS

Average screening time was 5.4 +/- 1.6 minutes (LEA), 1.9 +/- 0.9 minutes (RDE), and 1.7 +/- 1.0 minutes (NCAR). Test time for NCAR and RDE fell by 40% during the study period. Overall testability was 92% (LEA), 96% (RDE), and 94% (NCAR). Testability among 3-year-olds was 73% (LEA), 96% (RDE), and 89% (NCAR). Reliability of LEA was moderate (r = .59). Reliability of NCAR was high for astigmatism (Cyl) (r = .89), moderate for spherical equivalent (SE) (r = .66), and low for anisometropia (ANISO) (r = .38). Correlation of cycloplegic autorefraction (CAR) with gold standard cycloplegic retinoscopic refraction (CRR) was very high for SE (.85), CYL (.77), and moderate for ANISO (.48).

CONCLUSIONS

With NCAR, physician extenders can quickly and reliably detect astigmatism and spherical refractive error in one-third the time it takes to obtain visual acuity. LEA has a lower initial cost, but is time consuming, moderately reliable, and more difficult for 3-year-olds. Shorter examination time and higher reliability may make NCAR a more efficient screening tool for refractive amblyopia in younger children. Future study is needed to determine the sensitivity and specificity of NCAR and other screening methods in detecting amblyopia and amblyopia risk factors.

Predictive value of photoscreening and traditional screening of preschool children

PURPOSE

To compare the usefulness of traditional vision screening and photoscreening of 3- and 4-year-old children in the pediatrician's office.

METHODS

Following training of pediatricians and office staff, six pediatric clinics used both the MTI PhotoScreener (Medical Technology Industries, LLC, Riviera Beach, FL) and traditional acuity and stereopsis screening materials (HOTV charts/Random Dot E tests as recommended by established AAP-MCHB-PUPVS guidelines) during well-child exams. Clinics used one testing method for a 6-month period and switched to the other for the following 6 months, in a randomized manner. Referred children received a complete eye examination with cycloplegic refraction by local ophthalmologists or optometrists who forwarded the results to Vanderbilt Ophthalmology Outreach Center. Amblyogenic factors were defined using standardized published criteria.

RESULTS

Six hundred five children were screened with the photoscreener and 447 were screened with traditional techniques. Mean time for screening was less with the photoscreener: 2.5 versus 5.9 minutes ( P < 0.01). Untestable rates were similar (18% vs 10%, respectively P = NS), but higher with the photoscreener due to one clinic's 70% unreadable rate. Referral rates were also similar: 3.8% versus 4.5%. The positive predictive value (PPV) rate differed greatly. With follow-up results obtained from 56% of referred children, 73% of photoscreening referred children (8/11 examined) had amblyogenic factors confirmed on formal eye exams, whereas all children referred using traditional screening methods (10/10 examined) were normal.

CONCLUSION

Photoscreening is more time efficient than traditional screening and has a significantly higher PPV in 3- and 4-year-old children. This study was unable to validate traditional screening techniques in this preschool age group. If these results can be replicated, support for traditional vision screening must undergo intense scrutiny, and attention should be turned toward making photoscreening feasible for widespread implementation.

The cost and yield of photoscreening: impact of photoscreening on overall pediatric ophthalmic costs

BACKGROUND

Approximately 5% of preschool-age children suffer from amblyopia. Many of them have high or unequal hyperopia. Amblyogenic risk factors frequently can be detected by photoscreening.

METHODS

Free photoscreening was offered to Alaskan children ages 1 to 5 from urban and rural screening hubs. Screened images were mailed to the Alaska Blind Child Discovery coordinating center for physician photoscreen interpretation, specifically seeking latent or anisometropic hyperopia. Parents and screeners then were mailed results and information about amblyopia. Follow-up examination data were tallied, and a cost-consequence analysis was developed for various vision screening paradigms and eye care.

RESULTS

From 1996 through 2003, a total of 13,255 screenings were performed with a positive interpretation rate of 4.7%. Penetrance of screening was 22% in urban and 44% in rural communities. Positive predictive value was estimated to be more than 90%. Average cost to screen and inform an Alaskan preschooler was approximately 10.67 dollars, and cost to detect amblyogenic risk factors by photoscreening in an Alaskan was approximately 206 dollars. Compared to American Academy of Pediatrics (AAP) 1995 guidelines, implementing photoscreening added 9%, while mandating complete prekindergarten examination added 49% to overall eye care.

CONCLUSIONS

MTI photoscreening achieved high community penetrance and high positive predictive value for latent hyperopia and other amblyogenic factors. When follow-up costs are considered, adding photoscreening to current AAP guidelines may add 112 dollars per child over 10 years, but probably would assist in the reduction of amblyopia. Penetrance of urban photoscreening likely will remain low unless pediatric vision screening guidelines and reimbursement are revised.