Screening for amblyopia during primary care visits is more cost-effective than screening in school settings and optometric examinations in kindergarten-aged children in Toronto, Canada, data suggest.

Because of the low prevalence of amblyopia among young children, a population-based screening program may not warrant the resources required, despite the added health benefits of a universal program, according to the researchers.

Afua Oteng Asare, OD, PhD

“Amblyopia is a public health problem. For this reason, population-wide approaches to detect and treat amblyopia are critical, and approaches such as school screening and mandated optometry exams have been recommended and introduced in some jurisdictions,” study author Afua Oteng Asare, OD, PhD, a research assistant professor at the University of Utah in Salt Lake City, told Medscape Medical News. Asare conducted the study as a PhD student at the University of Toronto, Toronto, Ontario, Canada.

“With increasing budgeting constraints and limited resources, policymakers are relying more on economic analyses that measure value-for-money to inform their decisions on programming,” she said. “Evidence comparing the cost-effectiveness of vision-testing approaches to the status quo is, however, limited.”

The study was published January 4 in JAMA Network Open.

Analyzing Costs

Despite recommendations for routine testing, a notable percentage of children in Canada and the United States don’t receive an annual vision exam. The percentage is even higher among children from low-income households, said Asare. Universal screening in schools and mandatory optometric examinations may improve vision care. But the cost-effectiveness of these measures is unknown for certain conditions, such as amblyopia, the prevalence of which ranges between 3% and 5% in young children.

In Ontario, Canada’s largest province with about 3 million children, universal funding for children’s annual comprehensive eye exams and vision screening during well-child visits is provided through provincial health insurance.

In 2018, the Ontario Ministry of Health introduced guidelines for administering vision screening in kindergartens by public health departments. However, school-based screening has been difficult to introduce because of increasing costs and budgeting constraints, the authors wrote. As an alternative to underfunded programs, optometric associations in Canada have advocated for physicians to recommend early childhood optometric exams.

The investigators analyzed the incremental costs and health benefits, from the perspective of the Ontario government, of public health school screening and optometrist-based vision exams, compared with standard vision screening conducted during well-child visits with primary care physicians. They focused on the aim of detecting amblyopia and amblyopia-related risk factors in children between ages 3 and 5 years in Toronto.

For the analysis, the research team simulated a hypothetical cohort of 25,000 children over 15 years in a probabilistic health state transition model. They incorporated various assumptions, including that children had irreversible vision impairment if not diagnosed by an optometrist. In addition, incremental costs were adjusted to favor the standard screening strategy during well-child visits.

In the school-based and primary care scenarios, children with a positive or inconclusive test result were referred to an optometrist for diagnosis and treatment, which would incur the cost of an optometric evaluation. If positive, children were treated with prescription glasses and additional patching for amblyopia.

The research team measured outcomes as incremental quality-adjusted life-years (QALYs), and health utilities were derived from data on adults, because of the lack of data on children under age 6 years with amblyopia or amblyopia risk factors. The researchers also estimated direct costs to the Ontario government, including visits with primary care doctors, optometrists, public health nurses, and contract screeners, as well as prescription glasses for children with vision impairment who receive social assistance. Costs were expressed in Canadian dollars (CAD).

Overall, compared with the primary care screening strategy, the school screening and optometric examination strategies were generally less costly and had more health benefits. The incremental difference in cost was a savings per child of $84.09 CAD for school screening and $74.47 CAD for optometric examinations. Optometric examinations yielded the largest gain in QALYs, compared with the primary care screening strategy, producing average QALYs of 0.0508 per child.

However, only 20% of school screening iterations and 29% of optometric exam iterations were cost-effective, relative to the primary care screening strategy, at a willingness-to-pay threshold of $50,000 CAD per QALY gained. For instance, when comparing optometric exams with primary care screenings, if the cost of vision screening was $11.50 CAD, the incremental cost-effectiveness ratio would be $77.95 CAD per QALY gained.

Results ‘Make Sense’  

“We were initially surprised that the alternative screening programs were not cost-effective, compared to status quo vision screening in well-child visits,” said Asare. “However, the results make sense, considering the study’s universal approach (screening all children regardless of their vision status) and the study’s consideration only of amblyopia, and not of refractive errors, which are even more common in kindergarten children.”

Asare noted the lack of current data on the rate of vision screenings conducted in childhood by primary care practitioners and on referrals to eye care providers for children with abnormal screenings. Data on vision health disparities and barriers to accessing vision care in young children also are scarce.

“My ultimate research goal is to create and evaluate evidence-based, cost-effective interventions to be used at the point of care by pediatric primary care providers to improve the quality of vision care for children, especially those from socioeconomically deprived backgrounds,” she said. “The take-home message is that school vision screening and mandated eye exams are excellent programs, but they may not be suitable for all contexts.”

Additional studies are needed to look at the cost-effectiveness of the different screening strategies for other aspects included in childhood vision tests, including binocular vision problems, refractive disorders, myopia, allergies, and rare eye diseases.

Significant Underestimation?

Susan Leat, PhD

Commenting on the findings for Medscape, Susan Leat, PhD, a researcher and professor emerita at the University of Waterloo’s School of Optometry and Vision Science, Waterloo, Ontario, Canada, said, “This study only considers amblyopia, and not all eye diseases and disorders, which significantly underestimates the cost-effectiveness of optometric eye exams.”

Leat, who wasn’t involved with this study, has researched pediatric optometry and visual development. She and colleagues are developing new tools to test visual acuity in young children.

“If all disorders were taken into account, then optometric testing would be by far the most cost-effective,” she said. “Optometrists can detect all disorders, including more subtle disorders, which if uncorrected or untreated, can impact a child’s early learning.”

The study authors reported no funding for the study. Asare and Leat reported no relevant disclosures.

JAMA Network Open. Published January 4, 2023. Full text.

Carolyn Crist is a health and medical journalist who reports on the latest studies for Medscape, MDedge, and WebMD.

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