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Results with photoscreener shown comparable to comprehensive exam
One ophthalmologist advocates standardized vision screening programs.
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In Omaha, as with many other cities across the country, we continue to have a significant number of school-age children who are not receiving any type of eye screening for a combination of reasons that include language barriers, a lack of transportation and, of course, financial problems.
Although Nebraska and Iowa recommend vision screening along with hearing tests and immunization for school-age children, many children fall through the cracks.
Realizing there was a huge need, I have always wanted to initiate a vision screening program to break down these barriers. This passion was also shared with nonprofit group Building Healthy Futures (BHF). The group was already providing dental and mental health services in the community. We convened the Omaha Child Vision Collaborative in 2015. Our mission was: To create a coordinated system for vision care that includes education, screening, diagnosing and treatment for underserved children in our city’s most impoverished communities by maximizing resources through cross-sector and interdisciplinary partnerships.
We proceeded to recruit volunteers and send them into the schools in low-income areas to perform vision screening in children. Originally, our program used the traditional visual acuity chart to screen children; if they failed, they were referred to an eye care provider. We soon found that, with 52,000 children in Omaha Public Schools, it would be impossible to screen them all. The test was inefficient, and we did not have enough volunteers.
Study: Eye chart vs. device
We then initiated a study to compare vision screening with an eye chart to a vision screening device-based method. For our purposes in the study, we adjusted the referral criteria, modifying them slightly and adding a stereopsis test. We also sought to include patients’ complaints plus those of parents, guardians or teachers. So, for example, if a patient passed the screening with the chart or the device and passed the depth perception test, but there were concerns, that would be a fail and the child would be referred.
Our data showed that the sensitivity and specificity as well as the positive and negative predictive values between the two methods was comparable, if not leaning more in favor of the device. Importantly, we could screen more efficiently, reaching more students.
During the study, 219 children (438 eyes) were screened using the photoscreener, and the results were compared to the gold standard comprehensive ophthalmic examination (Williams et al.). The mean age of the patients screened was 6 years. The photoscreener referred 46% for potential amblyopia. The standard examination identified 40% who were deemed to have amblyopia or amblyogenic risk factors (based on American Association of Pediatric Ophthalmology and Strabismus guidelines.)
When compared to the comprehensive exam, the device was shown to have an overall testability rate of 84.47% (34 failed readings), a sensitivity of 93.02%, specificity of 84.96%, false positive rate of 9.13%, false negative rate of 2.74%, positive predictive value of 80.00% and a negative predictive value of 94.96%.
Two years ago we began incorporating the device’s results along with patients’, parents’ and teachers’ concerns as referring criteria to an eye doctor.
Vision critical to learning
Researchers estimate that as much as 80% to 85% of learning, cognition and perception is mediated through vision. Significantly lower achievement test scores (Rosner), reduced letter and work recognition, receptive vocabulary, emergent orthography (Shankar et al.), and verbal and performance intelligence quotients (Williams et al.) among children with uncorrected hyperopia have been observed.
Amblyopia left undetected and untreated at an age early enough to improve it is the largest cause of preventable vision loss in children (Jonas et al.). The National Center for Children’s Vision Health shows that 10 states have no preschool or school-age vision screening requirements, and only 17 include preschoolers.
In our program, 25% fail the screening and require a referral to an eye care provider, highlighting that we have a significant number of children who require further evaluation and treatment. To ensure we identify more of these children, we need to be their advocate and push for the child to be evaluated further if there is an issue.
In Omaha, we now have a visionmobile that travels into low-income areas and provides the follow-up eye exam and treatment to children at their school.
Vision is critical to a child’s ability to learn, especially as they begin school. It is also integral to their ability to develop the eye-hand coordination needed for sports. Many children, however, are not being screened appropriately, so standardized vision screening programs are needed.
- References:
- Jonas DE, et al. JAMA. 2017;doi:10.1001/jama.2017.9900.
- Rosner J. J Am Optom Assoc. 1997;68:648-650.
- Shankar S, et al. Optom Vis Sci. 2007;doi:10.1097/OPX.0b013e318157a67a.
- Williams SM, et al. Dev Med Child Neurol. 1988;30:735-742.
- Williams T, et al. J Pediatr Ophthalmol Strabismus. 2018;doi:10.3928/01913913-20170703-18.
- For more information:
- Donny W. Suh, MD, is chief of pediatric ophthalmology and strabismus at Children’s Hospital and Medical Center and is associate professor at the University of Nebraska Medical Center, Omaha. He can be reached at: Donny.Suh@unmc.edu.
Disclosure: Suh reports no relevant financial disclosures.