Increased diligence to testing kids’ vision greatly improves identification of amblyopia. Photo: Getty images.

Children’s vision screening generally uses optotype-based visual acuity (VA) and instruments to measure amblyopia risk. New research comparing the diagnostic accuracy of the Spot Vision Screener (SVS; PediaVision, Welch Allyn) with that of a nurse-administered optotype VA test found 10% of preschool children failed one or both tests. Additionally, the team of Australian researchers report that several children who required ophthalmic intervention were missed if only one screening method was used.

The investigation enrolled 2,237 children from 38 schools over 10 months. All children with an abnormal result by either method as well as a cohort of randomly selected children who passed both assessments were seen at a tertiary pediatric ophthalmology clinic. Participants were roughly five years old. Approximately 6% of children failed the SVS test, while about 8% failed the VA screen, with 4% failing both.

A total of 59 participants who failed SVS testing—but who passed the nurse-administered VA screening—had mostly minor refractive errors. On the other hand, of the 101 children who had an abnormal nurse-administered VA screen but normal SVS results, the vast majority had normal refractions when tested in-clinic. Still, there were three patients in this category who had optic nerve disorders (optic atrophy, optic nerve coloboma and optic nerve hypoplasia) and one who had cerebral vision impairment. VA screening therefore detected patients with potential, even life-threatening conditions who were all missed by SVS, the authors noted.

The SVS test was able to predict amblyopia risk factors and/or reduced VA about 70% of the time, while the nurse-administered VA screen was lower at about 61%. The best detection results occurred when a hybrid method was used by combining failed VA screens and failed SVS tests (91%). However, researchers cautioned that this approach may increase the risk of missing children with sight impairment in the community.

The most sensitive method would be when a referral is generated when one or both screens fail, the researchers suggested, while automated screening was valuable in children who were non-compliant with the nurse-administered VA tests.

“If only one screening method was utilized, a number of children, who required ophthalmic intervention, would have been missed,” the authors wrote in their paper.

This is the first population-based study providing detailed comparative measures of diagnostic accuracy for two commonly used childhood vision screening strategies in preschool children, says researcher Shaheen Shah, Senior Medical Officer, Department of Ophthalmology, Queensland Children’s Hospital, South Brisbane. 

Although the two methods aren’t directly comparable, both outcomes (reduced VA and suprathreshold amblyopia risk factors) require further professional ophthalmic assessment, Dr. Shah suggests.

The study had an enrollment rate of 98% at the schools and 89% attendance to the tertiary eye clinic at the Queensland Children’s Hospital in Brisbane of screen failures, making it one of the most robust population-based studies for eye screening in the literature, Dr. Shah says.

The study also summarized the published literature on the effectiveness of nurse-based vision screening and the SVS in pediatric vision screening.  

“Our study reports that a number of children who required ophthalmic intervention were missed by either screening method and thus the most sensitive screening method was found to be when a referral is generated when either/or both screens fail,” Dr. Shah says.

Kapoor V, Shah SP, Beckman T, Cole G. Community based vision screening in preschool children; performance of the Spot Vision Screener and optotype testing. Ophthalmic Epidemiol. August 21, 2021. [Epub ahead of print].