Originally published in NKCF Update (November 2023).
Authors Drs. Liam Price and Daniel Larkin from London’s Moorfields Eye Hospital highlighted some differences between KC diagnosed in children (those <16 years old) and keratoconus in adults. The consensus among keratoconus experts has been that disease diagnosed in the very young is more profound and more likely to progress faster.
One significant distinction is delayed presentation. When the very young are diagnosed with KC, they are often at a much more advanced stage of disease. The authors suggest children (and especially special needs children) are less likely to complain about vision changes. Doctors hypothesize that a child’s ‘good’ eye compensates for vision loss or distortion in the fellow eye as KC progresses. Compare this to adults who are much more likely to notice and follow up changes to their binocular vision. Dr. Price notes that 28% of children are initially diagnosed with severe keratoconus, compared to 8% in adults.
Another issue that separates the pediatric from adult version of keratoconus is the increased prevalence and rapid rate of progression among children. Many believe this is the result of today’s better imaging technology. Tomography can detect subtle changes or signs of disease that would have been previously overlooked. The authors conclude the “true prevalence of keratoconus is difficult to assess as detection rates are dependent on access to corneal imaging.”
Monitoring KC relies on precise and reproducible imaging, and comparing images over time. At most follow-up visits, doctors will take several measurements: cornea thickness at different points, cornea steepness, or curvature of the front or back of the cornea. An out-of-the-ordinary measurement can raise a red flag, but because pediatric patients can be uncooperative, obtaining reliable data to make a diagnosis or evaluate progression can present a challenge.
The authors add that most information used by doctors to evaluate KC progression was compiled using adult data, with the assumption that corneas in children are identical to adult corneas. Without additional studies that establish normal and irregular measurements for the pediatric population, the predicted course of keratoconus is not fully understood. Price argues that “it is difficult to confidently recommend” procedures like cross linking to parents when the outcomes and long-term success of the procedure in young children is not fully known. The authors conclude that important knowledge gaps about pediatric keratoconus exist and should be addressed with additional research.
Reference: Diagnosis and management of keratoconus in the paediatric age group: a review of current evidence, Price LD, Larkin DFP, Eye (Lond) doi: 10.1038/s41433-023-02600-1. Online ahead of print. Jun 6 2023.