Spatial distribution of back scattering in the nuclear area of the non-cataractous human lens

Abstract

SUMMARYThe spatial distribution of back scattering from a vertical cross-section of the nuclear area in non-cataractous human lens was investigated. The cross-section was centred on the pupil. There is no significant difference in Scheimpflug photography has proved to be an important tool for quantitative measurements of lens nuclear transparency,l-1O Nuclear cataract develops symmetrically around the anterior-posterior axis, I I Therefore, one Scheimpflug photographic section is sufficient to represent the opacity in the nucleus. I I On the other hand, cortical cataract is always highly asymmetrical,1 2 so that even several photo graphic sections might not be sufficient for detecting a change in opacity in the cortex. 1 2 Therefore, Scheimpflug photography is a suitable technique for objective docu mentation of nuclear cataract but not cortical cataract. 13In principle, to detect any change in nuclear back scat tering an area as large as possible in the nucleus should be measured, and the cortical region should be excluded to

3 Year simvastatin treatment and lens nuclear back scattering

“…A primary analysis of the precision of the measurement method17 21 demonstrated that the variability between eyes of an individual, among photographs within an eye, and measurements within photograph is negligible compared with the variation from one occasion to another within an individual. Therefore, only one eye in each individual, one photograph from each eye, and one measurement of each photograph was considered.…”

Refractive index changes in the ocular lens result from increased light scatter

“…It has been observed that backscattered light from the nuclei of noncataractous lenses decreases as one moves away from the lens axis. 15 This suggests a very simple model of a nuclear cataract. Assume a spherically symmetrical distribution of protein aggregates such that backscattered light decreases from a maximum at the center to a minimum at a distance of 1 mm from the center.…”

Optische Schnittbild-Vermessung des vorderen Augenabschnittes nach Scheimpflug: Möglichkeiten und Grenzen - eine Übersicht12

“…Die Zunahme der Lichtstreuung in den einzelnen Zonen der Linse verläuft dabei zeitlich gesehen ab dem adulten Stadium recht gleichmäûig [46]. Auch beim alten Menschen bleibt in der Linse eine solche Profilierung der Lichtstreuung zwischen Rinde und Kern erhalten [41], vorausgesetzt es kommt zu keiner pathologischen Verdichtung durch äuûere oder innere, chemische oder physikalische Kataraktnoxen. Die senile Kernverdichtung stellt dabei bereits eine pathologische Zunahme der Lichtstreuung dar, die klinisch oft mit dem Sammelbegriff (prä-)senile Katarakt belegt wird [44].…”