ESCRS - FP18.05 - One-Year Clinical Experience With Pace (Second Generation Customized Corneal Cross-Linking ) To Reduce Corneal Topographical Asymmetry And Improve Vision In Patients With Keratoconus And Ectasia After Lasik

One-Year Clinical Experience With Pace (Second Generation Customized Corneal Cross-Linking ) To Reduce Corneal Topographical Asymmetry And Improve Vision In Patients With Keratoconus And Ectasia After Lasik

Published 2024 - 42nd Congress of the ESCRS

Reference: FP18.05 | Type: Free paper | DOI: 10.82333/52xa-f538

Authors: Farhad Hafezi* 1 , Emilio A. Torres-Netto 2 , Shady Awwad 3 , Enes Aydemir 2 , Mark Hillen 2 , Léonard Kollros 2 , Nikki L. Hafezi 2 , Francesco Versaci 4

1Ophthalmology,ELZA Institute AG,Zurich,Switzerland;Ophthalmology,NYU Langone Health,New York,United States;Ophthalmology,ELZA Institute,Dietikon/Zurich,Switzerland, 2Ophthalmology,ELZA Institute AG,Zurich,Switzerland, 3Ophthalmology,American University of Beirut,Beirut,Lebanon, 4Ophthalmology,CSO Italia,Scandicci,Italy

Purpose

PTK-assisted customized epi-on (PACE) corneal cross-linking (CXL) in keratoconus corneas involves a PTK (phototherapeutic keratotomy) over the cone while avoiding any stromal tissue removal. Several gradients are created to achieve the customized effect: First, the PTK area is an epi-off CXL area as opposed to the rest of the cornea, which is treated in an epi-on fashion. Second, once riboflavin is applied, this generates a riboflavin gradient, with highest concentrations in the epithelium-denuded (cone) region. A differential UV gradient is also applied, where the highest fluences are delivered over the cone. PACE achieves substantial corneal flattening, several diopters greater than first-generation customized CXL protocols.

Setting

ELZA Institute, Dietikon, Zurich, Switzerland.

Methods

This prospective study involved PACE being performed on 122 eyes with ectasia (keratoconus, n=118; post-laser refractive surgery ectasia, n=4).

We report on the 1-year topographic, tomographic and visual outcomes of eyes with either stable or progressive corneal ectasia that underwent PACE cross-linking.

The procedure was performed by one of two surgeons (FH, ETN) at a single site (ELZA Institute, Zurich). All patients underwent a comprehensive assessment of corneal topography and tomography using (Pentacam, Oculus; MS-39, CSO Italia), corneal biomechanics (Corvis ST, Oculus) and conventional visual acuity assessments before PACE, and at regular intervals post-surgery, as well as at the one-year follow-up visit.

Results

We will show how PACE successfully reduces corneal topographical asymmetry by up to 12 D and will detail the changes in topographic and biomechanical parameters reflecting corneal flattening and asymmetry reduction. Subgroup analyses will reveal demographic and pre-procedural corneal characteristics linked to significant flattening and regularization effects, alongside visual outcomes. assess if these effects are consistent across progressive and non-progressive ectasias.

Conclusions

By exploiting both riboflavin and UV light gradients, PACE cross-linking can deliver greater corneal regularization effects than earlier customized cross-linking approaches, all without removing any stromal tissue. PACE improves the quality of vision by not only flattening the steep areas of the keratoconus, but also by a coupling effect that regularizes the astigmatism in the upper cornea.

The results after one year of follow-up will better characterize this effect and identify key anatomical and demographic factors that influence the extent of this effect.