Regional mapping of molecular components of human liquid vitreous by dynamic light scattering.

The distribution of particle sizes was studied in six regions of human liquid vitreous samples. Particle sizes were calculated from dynamic light scattering measurements as hydrodynamic diameter of molecules. In general, particle sizes increased progressively from anterior (near lens) to posterior (near retina). A much weaker trend of increase in particle size was found from nasal to temporal regions. Relative concentrations of particles of certain sizes were calculated from dynamic light scattering parameters. Viscosity coefficients of liquid vitreous samples were measured in a semi-micro viscometer. Hyaluronan concentrations increased from anterior to posterior and the reverse was true for viscosity, implying that the lower concentration of hyaluronan near the lens was offset by increased molecular size. A similar concentration gradient was found with the 6 nm diameter particles, and to a lesser degree with the 15 nm particles. The identities of these proteins must be resolved by techniques of proteomics.