Pediatric Keratoconus and the Effectiveness of Cross Linking, With Gerald Zaidman, MD

At the 2025 New York State Ophthalmological Society Envision annual meeting, Gerald W. Zaidman, MD, professor of clinical ophthalmology and vice-chair of ophthalmology at New York Medical College, attended by Jeremy Applebaum, BA, a medical student at New York Medical College, presented their findings from a retrospective study investigating pediatric keratoconus (KCN) to identify topographic indicators for Collagen Cross-Linking (CXL) to halt or lessen disease progression.1

“Everybody with keratoconus is basically nearsighted,” Zaidman told HCPLive. “So, if you think about what a 12 or 13 year old does, unless they are some sort of athlete, they’re not looking at far things in the distance. They’re just looking up close at their iPad or their iPhone and he has no trouble seeing that. So, the nearsightedness doesn’t bother them.”

Keratoconus is a bilateral, asymmetric disease that often escalates to progressive thinning and steepening of the cornea. This results in decreased visual acuity and irregular astigmatism. Recent studies have connected keratoconus to ocular inflammation, despite historically being noted as noninflammatory.2

Corneal topography is typically used to detect and diagnose keratoconus early; however, incipient cases render a single parameter measurement insignificant, leading to the adopting of corneal pachymetry and higher order aberration data to confirm the disease’s presence. Severe cases of keratoconus are treated with corneal transplant surgery, while mild and moderate can be offset with spectacles or contact lenses.2

However, mild and moderate cases can also be treated through corneal cross-linking, a process using riboflavin and ultraviolet-A light to create covalent bonds in the corneal stroma. This increases stiffness of the corneal tissue, which withstands or prevents keratoconic progression. After its introduction in 2002, the procedure has proven its effectiveness to the point that some advocate for its immediate use in keratoconus cases to avoid unnecessary delays.3

Zaidman and Applebaum conducted a retrospective study of 31 patients aged 12-18, all of whom were diagnosed with KCN based on slit-lamp findings, vision loss, and corneal topography. Of these 62 eyes, 38 treated and 19 untreated were compared at initial presentation, while 5 were excluded on account of being too severe for CXL and instead required corneal transplant surgery.1

The team compared eyes based on anterior mean keratometry (AKm), posterior mean keratometry (PKm), and thinnest pachymetry (TTP) using a 2-tailed t-test. The same parameters were used to compare treated eyes before and after CXL for those who completed a 12-month follow-up visit.1

Zaidman and colleagues found that treated eyes had a mean AKm of 48.6 D, mean PKm of -7.3 D, and mean TTP of 453.3 µm, while untreated eyes had means of 44.5 D, -6.6 D, and 494.1 µm, respectively. The mean difference of AKm was 4.15 D (95% CI +/- 2.92 D; P = .006), mean difference of PKm was -.744 D (95% CI, +/- .51 D; P = .005) and TTP was -40.74 µm (95% CI, +/- 35.11 µm; P = .024).1

By the 12 month mark, 14 treated eyes from 13 patients were included in the post-CXL comparison; the remainder either failed to complete a 12-month post-op visit or were lost to follow-up. The team compared pre- and post-CXL topography, noting a statistically significant decrease in AKm (1.61 D; 95% CI, +/- 1.25 D; P = .015). Additionally, logMAR visual acuity in eyes with CXL improved by .06 between the first and last visit. None of the cross-linked eyes progressed to CTS.1

Zaidman and Applebaum concluded that any pediatric patient with KCN who presented with steeper AKm and PKm, as well as thinner corneas, should be considered for CXL treatment.1

“All children should get their eyes checked once a year by somebody,” Zaidman said. “And then if the child has less than perfect vision, they should immediately be sent to an eye care provider. Check their eyes, and then if they have an odd refractive error, something that doesn’t seem to be reasonable, or if they have a lot of astigmatism, then have some corneal topography done to determine if they have possible keratoconus. And if they do, then you go on to cross linking.”

References

1. Zaidman G, Applebaum J, Grimes K. Topographic Findings in the Eyes Of Children Treated with Collagen Cross-linking (CXL) for Keratoconus (KCN). Abstract presented at Envision in New York, NY on May 16th, 2025.

2. Santodomingo-Rubido J, Carracedo G, Suzaki A, Villa-Collar C, Vincent SJ, Wolffsohn JS. Keratoconus: An updated review. Cont Lens Anterior Eye. 2022;45(3):101559. doi:10.1016/j.clae.2021.101559

3. Angelo L, Gokul Boptom A, McGhee C, Ziaei M. Corneal Crosslinking: Present and Future. Asia Pac J Ophthalmol (Phila). 2022;11(5):441-452. Published 2022 Sep 1. doi:10.1097/APO.0000000000000557