Stem cells belong to a subgroup of undifferentiated cells in organisms, which has the features of proliferation, self maintaining, and self renewal, and may produce plentiful filial generation with functions. According to the researches on embryonic stem cells, retinal stem cells in adults, and intraocular tumor stem cells, stems cells exist in human embryo, adult retina, and also intraocular tumors like retinoblastoma and choroidal melanoma. Different stem cells transplanted into subretinal interspace or vitreous cavity may differentiate into structure of neurone or retina. Stem cells may become a newest target of the researches on pathogenesis and treatment of diseases. (Chin J Ocul Fundus Dis, 2007, 23: 83-86)
Objective To study the global and histological changes of myopia and explore its pathogenic mechanism. Methods Chicks were reared with monocular suture of eyelid. When myopia had been confirmed by optometry, eyeballs were removed and subjected subsequently to measurement and light and electron microscopies. Results Three dimensions in the eyeballs of suture group were all enlarged markedly and the mean diopter was -15.00D. Under the light microscope, rod outer segment elongated and connected With PREC in suture group. With micrometer measure, cartilaginous sclera thickened and retina became thinner. Under electron microscope, rod outer segment elongated and membrane disc was intact. In the cytoplasm of RPEC, the phagosomes containing fractions of the membrane disc of outer segment were remarkably decreased. Conclusion Early form deprivation may affect the drop of membrane disc and cause eyeball enlargement; thus, myopia forms. (Chin J Ocul Fundus Dis,1999,15:20-23)