Definition – What is the dermis?
The eye consists of the outer eye skin, which can be divided into two sections – the opaque sclera and the translucent cornea. The main part of the eye skin is formed by the strong sclera. The white sclera consists of firm connective tissue and envelops almost the entire eyeball, giving it its shape.
Due to the high proportion of collagen and elastic fibers, the sclera gives the eyeball its stability and forms the white of the eye. At the front part of the eye, the sclera merges into the translucent, vascular cornea. The cornea is more curved than the sclera. Due to this curvature or curvature, the cornea is involved in the refraction of light and bundles incident light rays.
Anatomy of the dermis
The dermis can be divided into three different layers under the microscope: The lamina episcleralis is responsible for the blood supply, and accordingly there are numerous blood vessels in it. The blood vessels, i.e. the capillaries (the smallest blood vessels) enter a network of elastic and collagen fibers. This layer thus forms a loose covering tissue.
In addition, immune cells, namely lymphocytes and macrophages, can be found in the lamina episcleralis. The substantia propria is located in the middle and consists of taut connective tissue and collagen fibers, which are strongly interwoven with each other and are thus 0.5 to 6 μm strong. This layer is also called the connective tissue layer, which has hardly any blood vessels.
The inner lamina fusca sclerae adjoins or merges with the choroid. This lamina is formed from a thin layer of bundles of fibrils, which are arranged like scissors. This layer also contains fibroblasts and melanocytes.
Are you interested in the structure of the eye and would like to know more?
- In the external episcleral lamina
- In the middle into the substantia propria
- Inside the Lamina fusca sclerae
The thickness of the dermis varies according to the region of the eye. In addition, the thickness of the sclera depends on the size of the eyeball; the larger the eyeball, the thinner the sclera.
It can range from 0.3 to 1 mm. At its central point, it is about 0.6 mm thick. At the border areas to the transparent layer, the cornea, the sclera covers the cornea like roof tiles. At the exit point of the optic nerve, the sclera has a recess of about 3.5 mm in size through which the nerve passes.
