Pediatric keratoconus prevalence higher than believed, may change care approach

March 6, 2024
Sensitive screening in pediatric populations can help promote early diagnosis and intervention, ultimately saving vision, improving patients’ quality of life and preventing the need for corneal transplantation surgery.
Pediatric Eye Exam with Young Girl - Keratoconus

Comprehensive pediatric eye examinations should routinely screen for keratoconus and keratoconus suspects, researchers say, after a landmark report suggests significantly higher keratoconus prevalence than commonly believed. 

Published in the journal Eye and Contact Lens, the study, supported by the International Keratoconus Academy of Eye Care Professionals (IKA) and the Illinois College of Optometry, found that by utilizing Scheimpflug tomography during a comprehensive eye examination clinicians identified keratoconus in a limited pediatric population at a far greater prevalence (1 in 334) than commonly accepted even among adults (1:2000). Although even this adult prevalence is considered an underestimate, with literature reporting a range between 1:50 to 1:750, the pediatric prevalence is not well established. Such is the case: the study results not only help further the profession’s understanding of pediatric keratoconus prevalence but also emphasize the importance of earlier screening for timely diagnosis, monitoring and treatment. 

Characterized by a thinning, irregularly shaped cornea, keratoconus distorts vision, increases light sensitivity, creates irritation and may lead to scarring over time. With typical onset in adolescent years and progressing into the second or third decade of life, keratoconus progression can be halted with corneal collagen cross-linking (CXL). However, CXL is most beneficial when intervention comes as early as possible and before measurable vision loss. 

“When pediatric populations are diagnosed with keratoconus, it tends to be more severe and progressive, so if we can diagnose them earlier on then we have the chance to intervene quickly and hedge against that progression,” notes Jennifer Harthan, O.D., study lead author and chief of the Cornea Center for Clinical Excellence at the Illinois Eye Institute. 

“We can see here that prevalence is higher in this (pediatric) population, especially in a U.S.-based population, than has been previously published, so it’s a huge responsibility for us to start looking for it when we have these patients in our chairs.” 

What did the study find? 

The prospective observational study of subjects ages 3 to 18 years old in the Chicago Public School system, presenting for a comprehensive eye examination at the Princeton Vision Clinic between 2017 and 2019, assessed the results of Scheimpflug corneal tomography to determine corneal thickness. 

Researchers found that of these 2,007 children: 

  • Six were classified as keratoconus for a prevalence of 1:334. 
  • Three were classified as keratoconus suspects for a prevalence of 1:669. 
  • Nine were classified as keratoconus or keratoconus suspects for a prevalence of 1:223. 

The average age of children with keratoconus was about 14.8 years old; the average age of keratoconus suspects was 11.3 years old; and the average age of keratoconus or keratoconus suspects was 13.7 years old. 

Researchers note that patients often maintain good binocular vision but become symptomatic when their dominant eye deteriorates, reducing binocularity. Ocular aberrations in the cornea can also be partially compensated by the high accommodative power of younger patients, researchers write. These factors may contribute to why patients only receive care once significantly impacted and why they may be more advanced at time of diagnosis. 

But early intervention is the key. In at least one prospective study of CXL, researchers found that the procedure not only halted the disease progression but also significantly improved uncorrected and best-corrected visual acuity and stabilized thinnest pachymetry over a three-year period. 

As Dr. Harthan explains, the findings of pediatric keratoconus prevalence in this population are significantly beneficial. While little literature is available on pediatric prevalence in the U.S., the most cited prevalence study among U.S. adults shows a prevalence of 1 in 1835. This outdated study used only retinoscopy or keratometry, subjectively looking only for scissors motion of light in the central 3 millimeters of the cornea, whereas recent developments in corneal diagnostics, such as Scheimpflug tomography, have helped to show significantly higher prevalence.  

“The fact that this is just one population in the U.S. is already showing a higher prevalence than in adults—this is huge,” Dr. Harthan says. “We weren’t expecting this but there’s certainly an opportunity for more work to be done and an opportunity to do great work for these patients.” 

Toward that end, Dr. Harthan suggests that sensitive diagnostic testing, such as corneal tomography, could be added as part of comprehensive pediatric eye examinations to help detect patients earlier. Also, she suggests the prevalence findings should be used to help educate caregivers and pediatricians to ensure these children aren’t slipping through the cracks. Doctors need to know that keratoconus is not a rare disease as was previously believed. This is even more important for pediatric optometrists, pediatric ophthalmologists, pediatricians and school health care workers to be aware of because their practices and clinics are dedicated to taking care of this population. Increased prevalence must translate to increased awareness. 

“We want to detect it and be able to intervene as early as possible so ultimately patients can have the best quality of life,” Dr. Harthan says. 

Learn more about keratoconus 

Dr. Harthan is set to present the comprehensive results of the study, encompassing all diagnostic criteria and clinical results during the forthcoming IKA Keratoconus Symposium on May 18-19, in Bethesda, Maryland. This symposium, dedicated to keratoconus, is a joint event uniting optometrists and ophthalmologists, and will be accessible both in-person and online. The symposium will also feature presentations from the most eminent keratoconus experts worldwide. Registration is free for active-duty service members, veterans, federal service doctors, students, residents and fellows. There will be 10 hours of COPE credits awarded for attending this event.  

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