Abstract
Background Information about corneal biomechanics is crucial for achieving satisfactory outcomes
after surgical corneal interventions, e.g., for astigmatic keratotomies, but also
to
identify corneas that are at risk for postoperative complications such as corneal
ectasia. Hitherto, approaches to characterize corneal biomechanics in an in vivo setting have yielded
only minor success, demonstrating the unmet medical need for a diagnostic technique
to measure ocular biomechanics.
Objective This review shall explain the mechanism of Brillouin spectroscopy and summarize the
current scientific knowledge for ocular tissue.
Methods PubMed research of relevant experimental and clinical publications, as well as reporting
of own experience using Brillouin spectroscopy.
Results Brillouin spectroscopy can measure different biomechanical moduli with a high spatial
resolution. Currently, available devices are able to detect focal corneal weakening,
e.g., in keratoconus, as well as stiffening after corneal cross-linking. Also, the
mechanical properties of the crystalline can be measured. Corneal anisotropy and hydration,
together with
the dependence on the angle of the incident laser beam in Brillouin spectroscopy,
are challenges in the precise interpretation of measured data. A clear advantage in
the detection of
subclinical keratoconus compared to corneal tomography, however, has not been shown
yet.
Conclusion Brillouin spectroscopy is a technique to characterize biomechanical properties of
ocular tissue in vivo. Published results confirm ex vivo data of ocular
biomechanics; however, further improvements in the acquisition and interpretation
of measured data are required until this technique can be used in a clinically viable
setting.
Key words
Brillouin - keratoconus - cornea - ophthalmology - biomechanics
