In vivo Brillouin-spectroscopy for keratoconus and cross-linking effect

Session Details

Session Title: Corneal Biomechanics

Session Date/Time: Monday 09/10/2017 | 08:00-10:30

Paper Time: 10:04

Venue: Room 2.1

First Author: : T.Seiler SWITZERLAND

Co Author(s): :    T. Koller   P. Shao   E. Amyra   T.G. Seiler   A. Yun        

Abstract Details

Purpose:

Keratectasia is detected today by shape anomalies of the cornea. Current diagnostic techniques cannot measure the stiffening effect of corneal crosslinking (CXL). Brillouin spectroscopy measures non-invasively biomechanical constants of tissue like the cornea. In this paper, the first clinically measured Brillouin-shifts of keratoconus corneas with and without CXL are compared.

Setting:

Institute of Refractive Surgery (IROC), Zürich, Switzerland and Wellman Center for Photomedicine, Harvard Medical School, Boston, USA

Methods:

Brillouin-shift measurements were performed using a Brillouin-microscope (Brillouin optical scanning system, Intelon Optics, Boston). In brief, the BOSS is mounted on a slitlamp table and the cornea is measured in a sitting position. Although in the majority of the patients a Brillouin-shift map was taken, here we present only the central readings. Two groups of keratoconus eyes, 35 each, were compared: one without and one at least 1 year after CXL. Only 1 eye per patient was included. In a third group, consisting of 5 eyes, the BOSS-measurements were taken preoperatively, 3 days after, and 1 month after CXL.

Results:

The reproducibility of the measurement (3 different days, same eye and same operator) was ±0.0072 GHz (SD). The keratoconus group without CXL had an average Brillouin-shift of 5.7159 ± 0.0212 GHz (range 5.67 to 5.76 GHz) compared to 5.7319 ± 0.0274GHz (range 5.70 to 5.79 GHz) in the CXL-group. The difference between crosslinked and non-cosslinked corneas was statistically significant (one-sided t-test p=0.02) and there was trend towards increasing CXL-effect with time. In the longitudinal group, the Brillouin-shift was significantly reduced at day 3 after CXL but was significantly increased at 1 month after CXL.

Conclusions:

This is the first report on the application of Brillouin microscopy in clinical routine. So far, Brillouin-microscopy appears to be the only method to detect clinically the effect of CXL. This opens the option of customizing CXL, in a way that very soft corneas receive more CXL including monitoring the effect achieved.

Financial Disclosure:

has significant investment interest in a company producing, developing or supplying product or procedure presented, research is funded, fully or partially, by a company producing, developing or supplying the product or procedure presented