The morphometric anatomy of the eye shells in the intermediate fetal period of human ontogenesis

The study of the processes of eye morphogenesis in the fetal period of ontogenesis is relevant from the point of view of understanding the mechanisms of the formation of physiological hyperopia in newborns and myopia in childhood later. The greatest transformations in the human fetus are subject to changes in the cornea and shells of the eyeball in the equator area and in the optic nerve disk area. In general, the eyeball grows and develops most actively in the intermediate fetal period of ontogenesis. However, the details of this process are not well understood. The aim of the study is to characterize the quantitative macro-microscopic anatomy of the shells of the eyeball in a human fetus in the intermediate fetal period of ontogenesis. Macroscopically and microscopically, the anatomy of the orbit and eyeball of the fetus at the age of 14-27 weeks was studied by histo-topography. Three age groups were studied: Group I (14-18 weeks) - 36% of observations, Group II (19-23 weeks) - 38% of observations, Group III (24-27 weeks) - 26% of observations, of which 50% of observations male and 50% female. Histo-topograms made it possible to characterize the morphology of all shells of the eyeball (fibrous, choroid and retina), as well as to trace their course in all its parts. The description of the mid-horizontal and mid-sagittal histo-tomograms, stained according to Van Gieson, is presented and a quantitative characteristic of the thickness of all shells of the eyeball in the equator, the posterior pole of the eye and the cornea is given, sex differences are established and their growth rates are indicated. In the intermediate fetal period of human ontogenesis, the anterior-posterior size of the eyeball changes from 6.91±1.22 mm to 12.25±1.61 mm. At some stages of the entire intermediate fetal period of human ontogenesis, the ratio of the thickness of the shells of the eye is comparable (thickness of the sclera - 51%, of the choroid - 29%, of the retina - 20%). The study of the growth rate of the thickness of the shells of the eyeball revealed its greatest increase in the studied period of ontogenesis in the region of the posterior pole (69.06%).