At the 2025 Winter Meeting of the European Society of Cataract and Refractive Surgeons (ESCRS), Prof. Farhad Hafezi (ELZA Institute, Zurich) was featured in Ocular Surgery News (OSN) discussing a novel approach to keratoconus management. The technique—ELZA-PACE, or PTK-assisted customized epithelium-on cross-linking—was highlighted in a Healio Video Perspective as an evolving method that combines tissue preservation with spatially guided cross-linking.
ELZA-PACE is a second-generation approach to customized corneal cross-linking, aiming to regular the shape of corneas with ectasias (e.g. those with keratoconus or post-LASIK ectasia) without using the laser to reshape the structural part of the cornea, the stroma, with laser ablation. The protocol integrates full-surface epi-on cross-linking with topographically customized epithelial removal.
Prof. Hafezi told OSN how the initial cross-linking step employs an epithelium-on protocol developed at ELZA over the past decade. This protocol is calibrated to achieve a biomechanical stiffening effect comparable to standard 10-minute epi-off cross-linking, while preserving epithelial integrity. The epithelial thickness profile is then obtained using an OCT-based MS-39 device to generate a Gaussian map of the cone.
Using this data, a custom PTK is performed with the Schwind Amaris excimer laser, targeting only the epithelium over the cone apex. No stromal tissue is removed. Following this, cross-linking is carried out using EMAGine’s corneal cross-linking device, C-eye.
The localized stiffening at the cone apex may promote biomechanical flattening, while the global epi-on treatment contributes to overall corneal stabilization. Prof. Hafezi told OSN how this redistribution may support improved corneal symmetry and topographic regularity in selected cases.
Patients with central or paracentral cones, K-values between 50 and 55 diopters, and relatively regular astigmatic patterns may be particularly well suited to this approach. Early clinical experience has shown improvements in corneal regularity and visual function in a subset of cases. Notably, the optical effects are attributed to cross-linking alone—the excimer laser serves solely to remove epithelium with submicron precision.
An additional benefit of this staged strategy is the option for subsequent wavefront-guided stromal ablation, if appropriate, once corneal stability is achieved.
ELZA-PACE adds to the growing spectrum of tissue-preserving interventions for keratoconus, reflecting ongoing refinement in customized, gradient-guided cross-linking protocols.
