DYNAMIC LIGHT-SCATTERING IN THE VITREOUS - PERFORMANCE OF THE SINGLE-MODE FIBER TECHNIQUE

We constructed an apparatus for dynamic light scattering (DLS) measure ments in the posterior chamber for the eye. The setup uses single-mode technology and, with regard to future clinical use, it is combined wi th a commercial ophthalmologic microscope. The scattering volume is il luminated with a Gaussian beam realized by coupling a HeNe laser into a single-mode fiber. The scattered light is measured using a single-mo de fiber receiver. The signal is processed with a digital autocorrelat or. Our measurements on the vitreous of post mortem porcine eyes show that DLS measurements in the posterior chamber are feasible and that i t is possible to keep the excitation intensity below the damage thresh old of the retina. In addition, absolute measurements of light scatter ing in toluene confirmed the validity of DLS theory for single-mode re ceivers.