MEASURING DYNAMICS OF SCATTERING CENTERS IN THE OCULAR FUNDUS DURING LASER HEATING

The study is focused on the analysis of the diffusing-wave-spectroscopy signal recorded invivo on the ocular fundus. The developed system is based on a modified commercial ophthalmic microscope equipped with a standard therapy laser diode. A beam splitter was used to couple the probe beam (HeNe laser beam) and to collect the scattered light from the fundus. A single photon counting module converted the scattered light intensity into an electrical signal that was processed by a digital correlator. The acquired intensity autocorrelation function has been exploited to determine the dimensionless mean-squared displacement of the scattering sites. The motion of the scattered sites was measured during the moderate temperature increase induced by the therapeutic laser diode. Temporal fluctuations of the signal revel motion of molecules and thus changes in tissues temperature and chorioretinal blood velocity. Experimental results show the ability of the system to detect motion of the scattering sites in the ocular fundus layers during laser heating.