Abstract

SA.05.02

Combination of intracorneal ring segments and corneal crosslinking in keratoconic eyes

Schmiedt K., Kermani O., Oberheide U., Farvili E., Mahac I., Gerten G.
Augenklinik am Neumarkt, Köln

Objective: The implantation of intracorneal ring segments (ICR) leads to an increase in visual acuity for most of keratoconic patients, although a direct impact of the ICR on the underlying biomechanical pathological mechanism is not obvious. Therefore a progression of the disease is very probable after ICR implantation.
Methods: From 2005 to 2006 we combined a UV collagene crosslinking procedure with an ICR implantation in 4 keratokonic eyes. After femtosecond laser assisted preparation of the corneal tunnel ICR (0.15 to 0.35 mm, Keravision) were implanted in the first step. 2 to 6 months later a collagene crosslinking procedure was performed, if visual acuity and refraction were stable.
Results: In all cases a significant increase in visual acuity was achieved. The average gain in best corrected visual acuity due to the ICR implantation was 2 lines, for uncorrected visual acuity 6 lines. The collagene crosslinking procedure did not change the uncorrected visual acuity three months postop, the best corrected visual acuity increase in average by one line. Although these results were stable in the first months, 2 of the treated eyes showed a decreasing effect of the ICR implants. Therefore the single ring segment was replaced by two thicker segments (0.35mm). By this change a strong increase in visual acuity (up to 3 lines uncorrected) could be achieved. The higher order aberrations are drastically reduced by ICR implants for the central 3mm optical zone, the crosslinking procedure stabilised these results.
Conclusions: An ICR implantation can be in general combined with an UV crosslinking procedure. This crosslinking procedure changes the mechanical properties in such a strong way, that the thickness of the ICR and the timepoint of implantation have to be reconsidered. Further studies have to show, which combination of these procedures leads to clinical long-term stability of the results.

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