Automated, computerized, feature-based phenotype analysis of slit lamp images of the mouse lens

The significance of growth shells in development of symmetry, transparency, and refraction of the human lens

Human visual function depends on the biological lens, a biconvex optical element formed by coordinated, synchronous generation of growth shells produced from ordered cells at the lens equator, the distal edge of the epithelium. Growth shells are comprised of straight (St) and S-shaped (SSh) lens fibers organized in highly symmetric, sinusoidal pattern which optimizes both the refractile, transparent structure and the unique microcirculation that regulates hydration and nutrition over the lifetime of an individual. The fiber cells are characterized by diversity in composition and age. All fiber cells remain interconnected in their growth shells throughout the life of the adult lens. As an optical element, cellular differentiation is constrained by the physical properties of light and its special development accounts for its characteristic symmetry, gradient of refractive index (GRIN), short range transparent order (SRO), and functional longevity. The complex sinusoidal structure is the basis for the lens microcirculation required for the establishment and maintenance of image formation.

Optical properties of the lens: an explanation for the zones of discontinuity

The structural basis of zones of discontinuity in the living human eye lens has not been elucidated, and there is no conclusive explanation for what relevance they may have to the structure and function of the lens. Newly developed synchrotron radiation based X-ray Talbot interferometry has enabled the detection of subtle fluctuations in the human eye lens which, when used in mathematical modelling to simulate reflected and scattered light, can recreate the image of the lens seen in the living human eye. The results of this study show that the zones of discontinuity may be caused by subtle fluctuations in the refractive index gradient as well as from random scattering in the central regions. As the refractive index contours are created by cell layers with progressively varying protein concentrations, the zones are linked to growth and will contain information about ageing and development. The index gradient is important for image quality and fluctuations in this gradient may add to quality optimisation and serve as models for designs of new generation implant lenses.