Corneal Tomographic Changes After Modified Dresden Protocol Cross-Linking In Pediatric Keratoconus: A Long-Term Pentacam Study

To evaluate the long-term corneal tomographic changes after corneal collagen cross-linking (CXL) using a modified Dresden protocol in pediatric patients with progressive keratoconus.

Department of Ophthalmology, Alexandria University Hospitals, Faculty of Medicine, University of Alexandria, Egypt.

Retrospective, non-randomized interventional study including 30 eyes of 15 patients (<18 years) with keratoconus and minimum corneal thickness ≥400 μm. All eyes underwent epithelium-off CXL using transepithelial PTK-assisted epithelial removal followed by riboflavin 0.1% and UVA irradiation (3 mW/cm² for 30 minutes). Pentacam HR tomography was performed preoperatively and at 3, 6, and 12 months, then annually up to 5 years. Keratometry (K1, K2, Kmax), pachymetry, anterior/posterior elevation, Q value, and topographic indices were analyzed.

Mean age was 13.33±2.51 years with a mean follow-up of 2.9±1.27 years. Significant reduction in K1 and K2 was observed at 3 and 6 months (p≤0.044), with stabilization thereafter. Kmax showed early flattening (p=0.048) and remained stable long-term. Q value shifted toward less prolate corneas up to 2 years (p<0.001). Anterior elevation decreased significantly up to 3 years. Central and thinnest pachymetry showed significant early reduction at 3 months (p<0.001) without further significant progression. ISV and KI improved significantly early postoperatively.

Modified Dresden protocol CXL in pediatric keratoconus resulted in significant early corneal flattening and improvement in tomographic indices, followed by long-term stabilization. Despite an initial reduction in corneal thickness, no progressive thinning was observed. These findings support the safety and efficacy of epithelium-off CXL in halting disease progression in pediatric patients, emphasizing the importance of early intervention in this high-risk group.