Photoscreening
What is it and why are we seeing more of it?
With back to school, many parents are getting their forms filled out and it has me thinking about a routine primary care practice - the vision screen. In recent years, this basic component of well child care has become more complicated.
Traditional vision screening uses a chart like this.
But the vision screening of the future, especially for kids younger than 5 may look more like this.
Before we discuss the newer technology, let’s review why we screen. Vision screening is probably one of the most important things that happens at the pediatrician, but few people discuss it.
Amblyopia is a condition where your brain recognizes that one eye is stronger than the other and essentially begins ignoring the bad eye. Once this happens around age 8, it can lead to irreversible vision problems, even if the “bad” eye is corrected, the brain will still ignore it’s input and the child will be left with vision from one eye leading to worse depth perception.
So early vision screening is important, we look at the eyes, the alignment, the movement, we ask about behavioral indicators of poor vision, and we test the child’s vision.
We try to pick up strabismus (ie. Lazy eye or alignment issues), astigmatism (irregular curvature of the eye), refractive troubles with vision (near or far sightedness), cataracts (cloudiness), and droopy eyelids because often these problems can be treated to prevent amblyopia and lead to more balanced, healthier eyesight.
Of course, a baby can’t identify letters on a chart, and normally it’s around 4 or 5 that a traditional “snellen” chart can be use, where a child identifies the letters or symbols in rows that get progressively smaller one eye at a time. But despite this in the US, 4-8% of pediatric vision abnormalities are missed, either children don’t get the screening or the screening fails to identify the problem.
Over the past 10 years photoscreening devices have become increasingly available. They use image analytics to check the alignment and shape of the eye and are very sensitive at picking up strabismus, astigmatism, and refractive issues. All the child has to do is look, not read or talk, so these devices can be used 12 months and up. In 2012, The American Academy of Pediatrics and the American Academy of Ophthalmology (and 2 other ophthalmology societies), put out a policy statement encouraging the use of photo screening before age 3 “electively” or between 3-5 as an alternative to conventional vision screening.
Despite this, the devices haven't been consistently used or rapidly embraced. Why? Use of the photoscreeners can lead to earlier identification that can lead to earlier intervention, improving vision sooner and sometimes more comprehensively. When we see conditions identified that wouldn’t otherwise be, it’s always seems that more testing is an obvious “win” and a must.
But the drawback to photoscreening is that the technology is very sensitive with a positive predictive value of about 0.6. This means that about 4 out of 10 patients who receive abnormal results and a referral to a qualified vision provider will not have a problem identified in comprehensive examination. These extra potentially unnecessary visits have costs, including the stress of extra intervention and parental missed work. Additionally, when we think about the 6 real problems identified, some or even most of those would have been identified with the traditional screening and we have to consider what is the added benefit of interventions occurring potentially a year earlier (if you are interested this seems low).
However, if your child is not on a developmental trajectory to be able to read a snellen chart or if your child is higher risk for vision problems (ie. preterm birth or genetic conditions), the technology is really useful. Some children will benefit from intervention earlier. Weighing the pro’s and con’s is more complex than it might seem at first.
All this to say, photoscreening is cool technology, but if your practice doesn’t offer it, I wouldn’t worry. In fact, the practice where I take my children does not offer photoscreening. Since the AAP recommends photoscreening, insurance reimburses it, but sometimes reimbursement is not sufficient to cover the cost, especially for small private practices. At the large hospital associated federally qualified health center in the Bronx where 50 doctors and 25,000 patients could share one device, it was feasible, but the small practice where my kids go they do not have one. I’ll be interested to see these devices hopefully improve over time, become cheaper, more accurate and more universally adapted. I am hopeful this is an area where technologic innovation will help children.
I am tired of talking about COVID-19, but I posted about it yesterday trying to spread some hope. Though it feels like it will never end, it will. Delta is leading to more cases because it’s inherently much more infectious (without precautions, 4 people get sick per case as opposed to 2.5 with the original strains). The vaccines are working to prevent hospitalization and severe illness, and highly vaccinated communities will see the pandemic end before places where adults choose not to vaccinate. It’s not too late to be a cart returner and get your vaccine to protect your community.
I just read Melinda Moyer’s new book “How to raise kids who aren’t assholes: Science-based strategies for better parenting from tots to teens” and I am so impressed! It offers great advice about how to foster kind children who are positive members of society, something that anchors a lot of parenting goals. I’d encourage you to check it out.
Also, I am excited to be hosting Emily Oster to celebrate the publication of her new book “The Family Firm: A data-driven guide to better decision making in the early school years.” If you are near the Hamptons on 8/11, consider joining us at 11a at the Hampton Library in Bridgehampton or at 2p at the Children’s Museum of the East End.
That’s all for now! Drop a comment and let me know what’s on your mind!