Predicted light scattering from particles observed in human age-related nuclear cataracts using mie scattering theory.
نویسندگان
چکیده
PURPOSE To employ Mie scattering theory to predict the light-scattering from micrometer-sized particles surrounded by lipid shells, called multilamellar bodies (MLBs), reported in human age-related nuclear cataracts. METHODS Mie scattering theory is applicable to randomly distributed spherical and globular particles separated by distances much greater than the wavelength of incident light. With an assumed refractive index of 1.40 for nuclear cytoplasm, particle refractive indices from 1.33 to 1.58 were used to calculate scattering efficiencies for particle radii 0.05 to 3 microm and incident light with wavelengths (in vacuo) of 400, 550, and 700 nm. RESULTS Surface plots of scattering efficiency versus particle radius and refractive index were calculated for coated spherical particles. Pronounced peaks and valleys identified combinations of particle parameters that produce high and low scattering efficiencies. Small particles (<0.3 microm radius) had low scattering efficiency over a wide range of particle refractive indices. Particles with radii 0.6 to 3 microm and refractive indices 0.08 to 0.10 greater (or less) than the surrounding cytoplasm had very high scattering efficiencies. This size range corresponds well to MLBs in cataractous nuclei (average MLB radius, 1.4 microm) and, at an estimated 4000 particles/mm(3) of tissue, up to 18% of the incident light was scattered primarily within a 20 degrees forward cone. CONCLUSIONS The calculated size of spherical particles that scatter efficiently was close to the observed dimensions of MLBs in cataractous nuclei. Particle refractive indices only 0.02 units different from the surrounding cytoplasm scatter a significant amount of light. These results suggest that the MLBs observed in human age-related nuclear cataracts may be major sources of forward light scattering that reduces contrast of fine details, particularly under dim light.
منابع مشابه
A Computer Modeling of Mie-Scattering by Spherical Droplets Within the Atmosphere
The Earth’s atmosphere is an environment replete with particles of differ-ent sizes with various refractive indices which affect the light radiation traveling through it. The Mie scattering theory is one of the well-known light scattering techniques ap-plicable to modeling of electromagnetic scattering from tiny atmospheric particles or aerosols floating in the air or within the clouds. In this...
متن کاملMultilamellar spherical particles as potential sources of excessive light scattering in human age-related nuclear cataracts.
The goal of this project was to determine the relative refractive index (RI) of the interior of multilamellar bodies (MLBs) compared to the adjacent cytoplasm within human nuclear fiber cells. MLBs have been characterized previously as 1-4 μm diameter spherical particles covered by multiple lipid bilayers surrounding a cytoplasmic core of variable density. Age-related nuclear cataracts have mor...
متن کاملMie light scattering calculations for an Indian age-related nuclear cataract with a high density of multilamellar bodies
PURPOSE Multilamellar bodies (MLBs) are lipid-coated spheres (1-4 microm in diameter) found with greater frequency in the nuclear region of human age-related cataracts compared with human transparent lenses. Mie light scattering calculations have demonstrated that MLBs are potential sources of forward light scattering in human age-related nuclear cataracts due to their shape, size, frequency, a...
متن کاملDistribution, spherical structure and predicted Mie scattering of multilamellar bodies in human age-related nuclear cataracts.
PURPOSE To characterize multilamellar bodies (MLBs), determine their distribution along the optic axis and predict their potential Mie scattering within human age-related nuclear cataracts. Previous studies restricted to the equatorial plane have shown that MLBs are rare spherical objects that are 1-4 microm in diameter and covered by multiple layers of thin lipid-rich membranes. METHODS Eigh...
متن کاملInteraction of Laser Beam and Gold Nanoparticles, Study of Scattering Intensity and the Effective Parameters
In this paper, the optical properties of gold nanoparticles investigated. For this purpose the scattering intensity of a laser beam incident on gold nanoparticles has been studied using Mie theory and their respective curves versus different parameters such as scattering angle, wavelength of the laser beam and the size of gold nanoparticles are plotted. Investigating and comparison of the depi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Investigative ophthalmology & visual science
دوره 48 1 شماره
صفحات -
تاریخ انتشار 2007