Brillouin Spectroscopy of Normal and Keratoconus Corneas.

Seiler, Theo G.; Shao, Peng; Eltony, Amira; Seiler, Theo; Yun, Seok-Hyun (2019). Brillouin Spectroscopy of Normal and Keratoconus Corneas. American journal of ophthalmology, 202, pp. 118-125. Elsevier Science 10.1016/j.ajo.2019.02.010

[img] Text
Brillouin Spectroscopy of Normal and Keratoconus Corneas AJO.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (5MB) | Request a copy

PURPOSE To investigate the age dependence of Brillouin spectroscopy of the cornea and to compare normal and keratoconus corneas. DESIGN Retrospective case-control study. METHODS Study Population: Healthy patients and patients suffering from keratoconus seen at the Institut für Refraktive und Ophthalmo-Chirurgie (IROC) between December 2016 and March 2017. Brillouin frequency shifts of patients of 2 different groups were examined with Brillouin spectroscopy perpendicular to the corneal surface. Group 1 consisted of 47 healthy eyes, whereas Group 2 included 36 eyes with keratoconus of unclear progression. Besides Brillouin examinations, corneal tomographies were acquired so that correlations and comparisons between geometric parameters and Brillouin frequency shifts could be evaluated. MAIN OUTCOME MEASURES Corneal Brillouin frequency shifts averaged over full corneal thickness. RESULTS A significant correlation between age and central Brillouin frequency shift was identified (P = .011) with an increase in Brillouin frequency shift of 4 MHz per decade in normal corneas. Keratoconus corneas have a significantly reduced Brillouin frequency shift at the thinnest point compared to normal corneas (5.7072 ± 0.0214 vs 5.7236 ± 0.0146 GHz, P < .001). The Brillouin frequency shift at the point of maximum posterior elevation showed best correlation with geometry-derived keratoconus indices. The receiver operating characteristic curve analysis of Brillouin frequency shift showed substantially worse sensitivity and specificity compared to K and thinnest pachymetry for keratoconus detection. CONCLUSION Noninvasive Brillouin spectroscopy adds clinical information about the biomechanical state of the cornea perpendicular to the surface. An age-dependent stiffening of the cornea has been found and keratoconus corneas are statistically significantly different from normal corneas, but for precise differentiating of keratoconus stages (including normal corneas) the method is currently neither specific nor sensitive enough. Further development including standardized mapping and establishment of new indices may increase the potential of Brillouin spectroscopy substantially.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Ophthalmology

UniBE Contributor:

Seiler, Günter Theodor Michael


600 Technology > 610 Medicine & health




Elsevier Science




Günter Theodor Michael Seiler

Date Deposited:

07 Aug 2019 14:23

Last Modified:

22 Oct 2019 17:20

Publisher DOI:


PubMed ID:





Actions (login required)

Edit item Edit item
Provide Feedback