Evaluation of biomechanical changes and corneal stiffening after corneal cross-linking in progressive keratoconus: a prospective follow-up study using an air-puff applanation Scheimpflug analyser

Session Details

Session Title: Presented Poster Session: Corneal Cross-Linking

Venue: Poster Village: Pod 3

First Author: : R.Herber GERMANY

Co Author(s): :    M. Francis   E. Spoerl   L. Pillunat   F. Raiskup   A. Roy           

Abstract Details

Purpose:

To analyze the biomechanical changes and corneal stiffening after accelerated corneal cross-linking (A-CXL) in patients with progressive keratoconus using a dynamic Scheimpflug analyzer (Corvis ST).

Setting:

Department of Ophthalmology, Univ. Hospital Carl Gustav Carus, TU Dresden, Germany; Narayana Nethralaya Foundation, Bangalore, India.

Methods:

Eighty eyes of 80 keratoconic patients were enrolled in this study. 40 eyes with stable keratoconic findings were used as controls. 40 keratoconic eyes have shown progression and were cross-linked with the modified Dresden protocol (9mW/cm2, 10 min). All eyes were examined with the Corvis ST and Pentacam (Oculus, Wetzlar, Germany) after 6 and at least 12 months. Dynamic corneal response (DCR) parameters, topographical and tomographical parameters were analyzed with the linear mixed model using SPSS 25. Taking into account pachymetric changes after cross-linking, parameters were adjusted by corneal thickness.

Results:

Mean age, biomechanical intraocular pressure (bIOP), maximal keratometry (Kmax) and thinnest corneal thickness (TCT) did not differ between both groups at baseline (P>0.05). TCT, Kmax and DCRs remained stable in the control group over 12 months. In the CXL group, TCT decreased significantly after 6 months and recovered to baseline values after 12 months, whereas Kmax decreased by -0.84±3.39D. In DCR, a significant increase of bIOP and adjusted SPA1 was observed in CXL group by +1.47±2.57mmHg and +7.1±13.1mmHg/mm at 6 months and +1.71±2.76mmHg and +9.9±14.7mmHg/mm after 12 months, respectively (all P<0.05).

Conclusions:

SPA1 and bIOP showed significantly higher values after CXL, whereas the control group remained stable after the same follow-up period. The increase of SPA1 became significant after considering the pachymetric changes after CXL. BIOP, however, is less influenced by main corneal parameters and age. Therefore bIOP seems to be a valuable parameter to evaluate significant changes in biomechanical properties after CXL.

Financial Disclosure:

None