THE EMBRYONIC-DEVELOPMENT OF THE HUMAN LAMINA-CRIBROSA

Objective To investigate the embryonic development of lamina cribrosa of human eyes. Methods The lamina cribrosa of 291 eyes were studied in cluding 260 eyes taken from embryos and fetus of 7 weeks to full term and 31 eyes from infants under 1 year of age by using light microscopy (LMS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Results From observations, it was found that the dev elopment of the lamina cribrosa was lagged behind the development of t he optic nerve. Conclusions In eyes taken from embryos or fetus less t han 4 months of pregnancy, only ectodermal primordium of the lamina cr ibrosa could be seen. The initial scleral part of the lamina cribrosa began its formation in the 5th month of fetus. The fibrous tissue orig inating from the choroid and optic nerve sheath contributed to the for mation of the lamina cribrosa in the 8th month fetus. At this time, th e morphology of the lamina cribrosa is similar to that of an adult, ho wever the thickness of the structure is still getting increased up to one year after birth.