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

Continued care and provision of glasses are necessary to improve visual and academic outcomes in children: Experience from a cluster-randomized controlled trial of school-based vision screening

OBJECTIVE

To assess the effectiveness of a kindergarten vision screening program by randomly assigning schools to receive or not receive vision screening, then following up 1.5 years later.

METHODS

Fifty high-needs elementary schools were randomly assigned to participate or not in a vision screening program for children in senior kindergarten (SK; age 5‒6 years). When the children were in Grade 2 (age 6‒7 years), vision screening was conducted at all 50 schools.

RESULTS

Contrary to expectations, screened and non-screened schools did not differ in the prevalence of suspected amblyopia in Grade 2 (8.6% vs. 7.5%, p = 0.10), nor prevalence of other visual problems such as astigmatism (45.1% vs. 47.1%, p = 0.51). There was also no difference between screened and non-screened schools in academic outcomes such as the proportion of children below grade level in reading (33% vs. 29%) or math (44% vs. 38%) (p = 0.86). However, more children were wearing glasses in screened than in non-screened schools (10.2% vs. 7.8%, p = 0.05), and more children reported their glasses as missing or broken (8.3% vs. 4.7%, p = 0.01), suggesting that SK screening had identified successfully those in need of glasses. Examination of individual results revealed that 72% of children diagnosed and treated for amblyopia in SK no longer had amblyopia in Grade 2.

CONCLUSION

The prevalence of amblyopia and other visual problems was not reduced in Grade 2 by our SK vision screening program, perhaps because of poor treatment compliance and high attrition. The results suggest that a single screening intervention is insufficient to reduce visual problems among young children. However, the data from individuals with amblyopia suggest that continuing vision care and access to glasses benefits children, especially children from lower socioeconomic class.

Vision screening outcomes of 4-5 year-olds reflect the social gradient

CLINICAL RELEVANCE

Children in socioeconomically disadvantaged communities often do not access follow-up eye care services when referred from vision screenings; whether this is due to lack of availability is not known. This paper highlights the need for vision and eye care for vulnerable children with practicing clinical optometrists well placed to provide vision care.

BACKGROUND

Vision impairments develop from a young age and may inhibit learning experiences and impact life outcomes. Vision screening to detect and refer vision abnormalities supports children in their education and prevents minor vision impairments from worsening. This research describes outcomes from a vision screening programme for 4- to 5-year-olds delivered in Queensland, Australia.

METHODS

The programme involved all prep children from participating schools in Queensland. Vision screening was conducted with the Parr 4 m Visual Acuity Test and Welch Allyn Spot Vision Screener. A cross-sectional study design was adopted. Descriptive data analyses explored the frequency of vision screening and referral outcomes. Inferential analyses examined associations between vision screening and referral outcomes with socio-economic indexes for areas (SEIFA) scores  .

RESULTS

Of 71,003 prep students screened, 4,855 (6.8%) received a referral recommendation. A higher proportion of children who received a referral recommendation was from more disadvantaged locations (?2 = 109.16, p < 0.001). Of the students referred, 3,017 were seen by an eye health professional. Further vision assessment of students by an eye health professional revealed that 43.3% of the referred children were diagnosed with a vision abnormality, 18.9% had no vision abnormality and 37.7% had an 'undetermined' diagnosis. A higher proportion of children confirmed with a vision abnormality were from more disadvantaged locations (?2 = 52.27, p < 0.001).

CONCLUSION

It is important that vision screening programmes target disadvantaged populations and support families of children who require further health assessment to access health services.

Prevalence of vision conditions in children in a very remote Australian community

CLINICAL RELEVANCE

Understanding the prevalence of vision conditions in a population is critical for determining the most appropriate strategies for detecting and correcting eye conditions in a community. This is particularly important in very remote regions where access to vision testing services is limited.

BACKGROUND

Although recent studies have provided detailed analyses of the prevalence of vision conditions in Aboriginal and/or Torres Strait Islander children in urban and regional areas of Australia, there is a paucity of research examining vision conditions in children in remote regions. Importantly, a significant proportion of the population in remote and very remote regions identify as Aboriginal and/or Torres Strait Islander people.

METHODS

Comprehensive eye examinations were provided to 193 primary school children in a very remote Australian region. Ninety eight percent of children identified as Aboriginal and/or Torres Strait Islander. The eye examination included measures of visual acuity, cycloplegic autorefraction, binocular vision and accommodative function, ocular health and colour vision. Previous history of eye examinations and refractive correction were assessed through parental questionnaire.

RESULTS

Although the average unaided vision in the population was good (mean: 0.02 ± 0.13 logMAR) and the prevalence of reduced unaided visual acuity (>0.3 logMAR in either eye) was low (4%), vision conditions were detected in 32% of children. The most common conditions were clinically significant refractive errors (18% of children) and binocular vision or accommodative disorders (16%). Of the total population of children tested, 10% had previously had an eye examination, and 2% were reported to have previously been prescribed spectacles.

CONCLUSIONS

In this population of children in a very remote Australian region, up to 1 in 3 children had a vision condition, with many of these conditions being uncorrected and undetected. These findings highlight the important need for additional resources to be made available to very remote communities for the detection and correction of vision conditions in childhood.

Positive predictive value of dual-modality vision screening in school children 4-7 years of age-a retrospective review in Queensland, Australia

PURPOSE

To report the outcomes and positive predictive value (PPV) of vision screening in schoolchildren 4-7 years of age through the Primary School Nurse Health Readiness Program (PSNHRP) in Queensland, Australia.

METHODS

A retrospective review of schoolchildren who underwent vision screening between January 2017 and December 2020 was conducted. Vision screening was performed through a dual-examination method, using the Parr 4m letter-matching vision test with crowding bars and the Spot photoscreener. Children were referred to an optometrist or ophthalmologist for review as required and if they failed either screening modality. PPVs were calculated based on whether a visual abnormality was confirmed by an ophthalmologist or optometrist.

RESULTS

Of 185,685 eligible children, 176,164 (94.9%) consented to vision screening, 164,890 (93.6%) consented children underwent vision screening, and of those 12,148 (7.4%) were referred for an eye assessment. Of the 8,659 children with a known outcome (71.3% of referred), 6,011 (69.4% of known outcomes) had a confirmed visual abnormality and 2,648 (30.6%) children did not. The PPV was 0.73 when a referral was indicated by the photoscreener result, 0.76 when indicated by visual acuity testing, and 0.91 when indicated by both the photoscreener and visual acuity testing.

CONCLUSIONS

The PSNHRP vision screening program showed a high uptake, and the dual screening method was effective in identifying visual abnormalities, with higher PPV when both visual acuity and photoscreener results indicated a need for referral.

Cost-effectiveness of Universal School- and Community-Based Vision Testing Strategies to Detect Amblyopia in Children in Ontario, Canada

IMPORTANCE

Screening for amblyopia in primary care visits is recommended for young children, yet screening rates are poor. Although the prevalence of amblyopia is low (3%-5%) among young children, universal screening in schools and mandatory optometric examinations may improve vision care, but the cost-effectiveness of these vision testing strategies compared with the standard in primary care is unknown.

OBJECTIVE

To evaluate the relative cost-effectiveness of universal school screening and mandated optometric examinations compared with standard care vision screening in primary care visits in Toronto, Canada, with the aim of detecting and facilitating treatment of amblyopia and amblyopia risk factors from the Ontario government's perspective.

DESIGN, SETTING, AND PARTICIPANTS

An economic evaluation was conducted from July 2019 to May 2021 using a Markov model to compare 15-year costs and quality-adjusted life-years (QALYs) between school screening and optometric examination compared with primary care screening in Toronto, Canada. Parameters were derived from published literature, the Ontario Schedule of Benefits and Fees, and the Kindergarten Vision Testing Program. A hypothetical cohort of 25 000 children aged 3 to 5 years was simulated. It was assumed that children in the cohort had irreversible vision impairment if not diagnosed by an optometrist. In addition, incremental costs and outcomes of 0 were adjusted to favor the reference strategy. Vision testing programs were designed to detect amblyopia and amblyopia risk factors.

MAIN OUTCOMES AND MEASURES

For each strategy, the mean costs per child included the costs of screening, optometric examinations, and treatment. The mean health benefits (QALYs) gained were informed by the presence of vision impairment and the benefits of treatment. Incremental cost-effectiveness ratios were calculated for each alternative strategy relative to the standard primary care screening strategy as the additional cost required to achieve an additional QALY at a willingness-to-pay threshold of $50 000 Canadian dollars (CAD) ($37 690) per QALY gained.

RESULTS

School screening relative to primary care screening yielded cost savings of CAD $84.09 (95% CI, CAD $82.22-$85.95) (US $63.38 [95% CI, US $61.97-$64.78]) per child and an incremental gain of 0.0004 (95% CI, -0.0047 to 0.0055) QALYs per child. Optometric examinations relative to primary care screening yielded cost savings of CAD $74.47 (95% CI, CAD $72.90-$76.03) (US $56.13 [95% CI, $54.95-$57.30]) per child and an incremental gain of 0.0508 (95% CI, 0.0455-0.0561) QALYs per child. At a willingness-to-pay threshold of CAD $50 000 (US $37 690) per QALY gained, school screening and optometric examinations were cost-effective relative to primary care screening in only 20% and 29% of iterations, respectively.

CONCLUSIONS AND RELEVANCE

In this study, because amblyopia prevalence is low among young children and most children in the hypothetical cohort had healthy vision, universal school screening and optometric examinations were not cost-effective relative to primary care screening for detecting amblyopia in young children in Toronto, Canada. The mean added health benefits of school screening and optometric examinations compared with primary care screening did not warrant the resources used.

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

Purpose

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

Material and Methods

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

Results

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

Conclusions

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

Translational Relevance

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

The UCI EyeMobile Preschool Vision Screening Program: Refractive Error and Amblyopia Results from the 2019-2020 School Year

Purpose

To introduce the University of California Irvine (UCI) EyeMobile for Children preschool vision screening program and describe the ophthalmic examination results of children who failed screening with the PlusoptiX S12C photoscreener during one school year.

Patients and Methods

Children aged 30-72 months were screened with the PlusoptiX using ROC mode 3 during the 2019-2020 school year. Children who failed screening were referred for comprehensive eye examination on the EyeMobile mobile clinic. Presence of amblyopia risk factors (ARFs), amblyopia, and refractive error was determined via retrospective review of records. 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. ARFs were defined using 2021 American Association for Pediatric Ophthalmology and Strabismus (AAPOS) instrument-based screening guidelines.

Results

5226 children were screened during the study period. Of the 546 children who failed screening, 350 (64%) obtained consent and were examined. Mean age of examined children was 4.45 years. Amblyopia was found in 8% of examined children, with unilateral amblyopia seen in 79% of amblyopic subjects. Glasses were prescribed to 246 (70.3%) children. Of the 240 children who received cycloplegic examinations, 43% had hyperopia and 30% had myopia. The positive predictive value (PPV) of the PlusoptiX screening for ARFs in children who received cycloplegic examinations was 70.4%.

Conclusion

A significant proportion of Orange County preschoolers with refractive errors and amblyopia have unmet refractive correction needs. The PlusoptiX S12C photoscreener is an adequate screening device for the UCI EyeMobile for Children program, although modification of device referral criteria may lead to increased PPV. Further research is necessary to understand and overcome the barriers to childhood vision care in our community.

A Comparative Study of Two Photoscreening Devices With Manual Vision Screening Involving Preschool Children

PURPOSE

To compare referral results from two photoscreening devices that are in wide use relative to a manual screening test protocol in preschool children.

METHODS

Children aged 3 to 5 years who attended preschools in two counties within the State of Michigan (N = 1,085) took part in the State's vision screening program, which included the Lea Symbols and Stereo Butterfly tests, during a 3-month period. All who failed this screening or were unable to be tested, and 20% of those who passed, were then invited to undergo testing with the Plusoptix Vision Screener Model S-12C (Plusoptix, Inc) and Welch Allyn SPOT Vision Screener Model VS-100 (Hill-Rom, Inc) photoscreening devices. Screening was conducted by State-trained technicians. With the State's test results considered the gold standard for screening, sensitivity and specificity of the two photo-screening devices were calculated. McNemar's test and logistic regression were used to evaluate the findings.

RESULTS

A total of 1,085 children took part in the State's screening program. Their mean ± standard deviation age was 48.8 ± 7.2 months, with a 51:49 female-to-male ratio, and a similar percentage were Black (34.1%) or White (33.3%). The sensitivity of the SPOT and Plusoptix screening was 61.0% and 65.2%, respectively. The specificity of the SPOT and Plusoptix screening was 92.9% and 82.4%, respectively. For 84 children who were unable to be tested by the State's screening, the SPOT and Plusoptix devices completed the screening on the majority (86.9% and 73.8%, respectively).

CONCLUSIONS

The photoscreening devices yielded numerous false-negative results and fewer false-positive results. Their ability to screen many children who could not be screened by manual testing indicates a useful application. [J Pediatr Ophthalmol Strabismus. 2022;59(1):46-52.].

Diagnostic accuracy of the Parr vision test, single crowded Lea symbols and Spot vision screener for vision screening of preschool children aged 4-5 years in Aotearoa/New Zealand

PURPOSE

Preschool children in New Zealand undergo vision screening to detect amblyopia at 4-5 years of age. The current test, the Parr vision test, does not meet international visual acuity chart guidelines and has not been validated against other commonly used paediatric vision tests. New Zealand vision screening protocols are also not targeted for detecting other eye conditions such as uncorrected refractive error, which may affect school performance. We compared the Parr vision test with the single crowded Lea symbols and the Spot vision screener for detecting ocular pathology, refractive error and amblyopic risk factors in preschool children.

METHODS

A cross-sectional diagnostic accuracy study recruited children aged 4-5 years via convenience sampling from the University of Auckland Optometry Clinic and through primary schools in Auckland, New Zealand. Participants received vision screening with the three different instruments administered by a lay screener. Comprehensive eye examinations were completed by a paediatric optometrist to determine the presence of vision disorders.

RESULTS

Of 197 children who received a comprehensive eye examination, 14 (7.1%) had amblyopic risk factors and 43 (21.8%) had significant refractive error (15.7% with astigmatism, 9.1% with hyperopia). The sensitivity for detecting any ocular condition did not differ significantly between the tests (50.0% for Parr, 43.5% for Lea, 42.5% for Spot). Specificity was significantly lower for the Parr vision test (80.8%) than for the Lea symbols (93.4%) and Spot vision screener (98.0%). Adding the Spot vision screener to measurements of visual acuity significantly improved sensitivity in detecting any ocular condition with the Parr vision test (67.5% for Parr/Spot vs 50% for Parr alone), but not with the Lea symbols (52.5% for Lea/Spot vs 43.5% for Lea alone).

CONCLUSION

The sensitivity of the Parr vision test for detecting ocular conditions in preschool children does not vary significantly from that achieved by the Lea symbols or the Spot vision screener. However, current New Zealand vision screening protocols could be improved by expanding the target conditions to include significant refractive error and incorporating the use of the Spot vision screener to increase the accuracy with which children with refractive error are identified. Future research should include longitudinal studies to determine the effect of preschool vision screening on later ocular and academic outcomes.

2020 Evaluation of Portable Vision Screening Instruments

Amblyopia is the most common cause of preventable visual impairment in children and occurs as a result of unilateral or bilateral impairment in best-corrected visual acuity. Early diagnosis and proper treatment are crucial to prevent poor visual outcomes in adulthood. Advances in technology have provided more objective diagnostic tools, which can now be used by a wide range of healthcare providers. Here, we highlight tools that have gained popularity in the past two decades and compare clinically relevant parameters to guide primary care providers seeking to incorporate instrumental vision screening in pediatric patient care.

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.

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.