Purpose: The morphology of the crystalline lens was studied by conventional staining techniques. The thickness of the capsule, the features of epithelial cells, and the distribution of inter fibrillar connective tissue were observed.
Methods: Eight eyes of young monkeys were examined. Resin-embedded specimens of the anterior segment were sectioned into 3 microm thickness in axial and coronal directions. Expanded antero-equatorial capsules were dyed without sectioning. LFB (Luxol Fast Blue), DAPI(diamidino-2-phenyl-indole), H-E (Hematoxylin-Eosin) and Masson's trichrome staining techniques were used. Light microscopy was used to evaluate and photograph. Pictures were composed for panoramic views.
Results: 1) The lens was fully enveloped by thick connective tissue the "capsule". The capsule was the thinnest in the posterior polar zone, and thickest in the peripolar zones with zonular bindings. The anterior polar and equatorial zones were 15 microm thick. 2 ) Single layered epithelial cells were squamous in the anterior polar zone and converted to cuboidal toward the equator. No epithelial cells were found thereafter in the posterior area. 3) Small and dense nuclei were observed within the anterior equatorial germinative zone. Epithelial cells were converted into fiber cells one by one in the posterior equatorial zone. Large oval nuclei of new fibers became smaller and sparser along the inner zone and then vanished. 4) Fibers were columnar in the cortex with rich intercalated connective tissues, and compressed centrally without interspaces.
Conclusion: Genetic multiplication of fibers in a small intracapsular capacity will continue uncontrollably throughout life. That will reduce inter fibrillar connective tissue, causing accommodative loosening and opacity with age.