Purchase this article with an account.
Oliver Stachs, Stephan Reiss, Rudolf F. Guthoff, Heinrich Stolz; Quantitative in vivo Imaging of Lens Elasticity using Brillouin Spectroscopy. Invest. Ophthalmol. Vis. Sci. 2011;52(14):1539.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The goal of this study was to develop a method to determine the elasticity of the crystalline lens using non-destructive means in vivo.
Spontaneous Brillouin scattering is an inelastic scattering process arising from inherent density fluctuations (or acoustic phonons) in the medium. It provides direct information on the phonon's properties that are closely related to the viscoelastic properties of samples. In order to separate Brillouin light from elastically scattered light, which arises from Rayleigh and Mie scattering, a fully parallel dispersive imaging spectrometer based on a virtually imaged phased array (VIPA) has to be used. The interference among the phased array beams provides angular dispersion, so that different frequency components are emitted at different angels. A confocal system (wavelength 780nm) was designed to determine the Brillouin frequency shift as well as the bulk modulus in backscattering geometry and first measurements using pig eyes was performed using the setup depicted in Figure 1.
The Brillioun frequency shift as well as the bulk modulus could be determined spatially resolved (volume size 1x10-5 mm³) using a measurement time of 1.0 sec for a single measurement point in undissected pig eyes and in rabbits eyes in vivo. Laser power was 12mW. In Fig 1 a 2D scan across a lens in a pig eye in axial direction is presented.
The developed in vivo method enables to determine the elasticity of the crystalline lens using non-destructive means. Further effect is necessary to reduce measurement time and block the elastic scattered components for increasing the signal to noise ratio. The technique can perform noninvasive, high-resolution, and quantitative maps of the whole lens elasticity. This technique could be real time and straightforward adapted for a very wide field of in vivo investigations in ophthalmology.Fig 1: Optical setup (left) and quantitative map of the bulk modulus of a pig eye lens (right)
This PDF is available to Subscribers Only