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

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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


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.


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


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.


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.


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

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