Abstract
Abstract: :
Purpose:We have used cylindrical map projections (CMPs), to plot primate fiber cell organization at every location around the equator in a single image from selected growth shells as a function of growth, development, and aging. These images were then correlated with azimuthal map projections (AMPs) to reveal suture formation during the same time period. Methods:CMPs have been used for decades as a means of projecting the features of a 3D spheroidal surface onto a 2D rectangular plot. In this manner, lens fibers are lines of longitude and lens suture branches are longitudinal arc lengths defined by degrees of latitude. Lens structural parameters were derived from slit–lamp, light and transmission and scanning electron micrographs. Suture formations were represented as AMPs, which are projections that are radially symmetric around a central point (the poles). Results:Throughout development, CMPs and AMPs show that ‘Y’ sutures are formed by precise ordering of straight and opposite end curvature fibers. The suture pattern is determined by the position of the straight fiber at the equator and poles. From birth through infancy, a 6–branched simple star suture is formed. CMPs reveal that anteriorly, 3 additional branches are added between the existing branches. Posteriorly, 6 new suture branches are added on either side of the existing branches. Each new branch is added in a staggered pattern starting in the inferonasal quadrant and proceeding in a clockwise direction, resulting in suture patterns that are offset in successive growth shells. Both the anterior and posterior suture branches are defined by straight fibers that do not reach either of the poles. From infancy through young adulthood a 9–branched star suture is formed in the same manner. Again 3 additional branches are added between existing branches anteriorly and 6 new suture branches are added on either side of 3 existing branches posteriorly. These branches are also defined by straight fibers that do not reach either pole. Finally, this pattern is repeated from adulthood into middle age as a 12–branched complex star suture is formed. Conclusions:The advantage of using CMPs is that the organization of every fiber in a growth shell can be observed in a single image. This comprehensive view of fiber cell organization permits more accurate measurements of fiber length (ongoing). Additionally, correlative use of CMPS and AMPs have now been used effectively to animate the lens development, growth, and aging in a temporal sequence.
Keywords: microscopy: electron microscopy • aging • anatomy