Data that Can Be Acquired from Optical Clearing Studies

In this chapter, we will describe methods based on simple measurements that allow one to acquire information of diverse nature. Regarding the characterization of optical clearing treatments and evaluation of their efficiency, we discuss a method to obtain the refractive index kinetics of the interstitial ground medium and another method to obtain the kinetics of the scattering properties of a tissue under study. The evaluation of the diffusion properties for the optical clearing agents and water involved in the fluxes between the tissue and the treating solution is also important. To obtain these properties, we describe in Sect. 6.4 a simple ex vivo method, which from collimated transmittance and thickness measurements allows one to estimate the diffusion time and the diffusion coefficient of these fluids. Such method can be used as a complementary diagnostic tool, since it allows also for discrimination between normal and pathological tissues. Also with the objective of obtaining physiological or pathological information from tissues, we describe in Sect. 6.5 the discovery of two new optical clearing windows in the ultraviolet range, which may turn possible the development of new diagnostic or treatment methodologies.