Scheimpflug imaging of corneas after collagen cross-linking

Tobias Koller, Hans Peter Iseli, Farhad Hafezi, Paolo Vinciguerra, Theo Seiler

Research output: Contribution to journalArticlepeer-review


PURPOSE: To compare geometrical shape factors of keratoconus corneas after cross-linking (CXL) by means of Scheimpflug imaging with those of untreated fellow eyes. SETTING: Institut für Refraktive und Ophthalmo-Chirurgie, Zürich, Switzerland. METHODS: Scheimpflug imaging of the anterior segments was performed with the Pentacam (Oculus, Wetzlar, Germany) in 21 patients with progressive keratectasia before and after CXL. Only 1 eye per patient was treated with corneal cross-linking using the riboflavin/UV-A approach, the fellow eye serving as control. The following corneal parameters and their postoperative evolution during 1 year after treatment have been evaluated: minimal curvature radius and its location, thickness at the thinnest point, location of the thinnest point, anterior and posterior elevation, conoid asphericity constants of the anterior and posterior surface, and 7 keratoconus indices. Statistical comparison was performed by means of the Wilcoxon test. RESULTS: None of the treated eyes showed topographic progression in contrast to the untreated group where 8 eyes experienced significant progression. Minimal curvature radius increased significantly after 1 year compared with preoperative (6.14-6.21 mm), whereas in the untreated fellow eye, it significantly decreased (6.94-6.86 mm). Minimal corneal thickness was significantly reduced after treatment (P <0.002 at 12 months). The cornea showed an evolution toward a more regular shape as indicated by a significant reduction in 4 of 7 keratoconus indices. No complications of CXL occurred in this small study group. CONCLUSIONS: After cross-linking, the corneal shape undergoes a process of regularization. This process is active during the first year after treatment and may continue. Longer follow-up is warranted to estimate the full amount of regression of the keratectasia after CXL.

Original languageEnglish
Pages (from-to)510-515
Number of pages6
Issue number5
Publication statusPublished - Jun 2009


  • Cross-linking
  • Keratoconus
  • Riboflavin
  • Scheimpflug imaging

ASJC Scopus subject areas

  • Ophthalmology


Dive into the research topics of 'Scheimpflug imaging of corneas after collagen cross-linking'. Together they form a unique fingerprint.

Cite this