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The stroma is a delicate interlacement of fibres. Some circle the circumference of the iris and the majority radiate toward the pupil. Blood vessels and nerves intersperse this mesh. In dark eyes, the stroma often contains pigment granules. Blue eyes and the eyes of albinos, however, lack pigment.
The iris consists of two layers: the front pigmented fibrovascular layer known as a stroma and, behind the stroma, pigmented epithelial cells.. The stroma is connected to a sphincter muscle (sphincter pupillae), which contracts the pupil in a circular motion, and a set of dilator muscles (dilator pupillae), which pull the iris radially to enlarge the pupil, pulling it in folds.
The anterior segment or anterior cavity [1] is the front third of the eye that includes the structures in front of the vitreous humour: the cornea, iris, ciliary body, and lens. [2] [3] Within the anterior segment are two fluid-filled spaces: the anterior chamber between the posterior surface of the cornea (i.e. the corneal endothelium) and the ...
They are arranged in a circle, and form a sort of frill behind the iris, around the margin of the lens.. They vary from sixty to eighty in number, lie side by side, and may be divided into large and small; the former are about 2.5 mm. in length, and the latter, consisting of about one-third of the entire number, are situated in spaces between them, but without regular arrangement.
The irises of human eyes exhibit a wide spectrum of colours. Eye color is a polygenic phenotypic trait determined by two factors: the pigmentation of the eye's iris [1] [2] and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris.
Micrographs and 3D drawing of a "foot" structures on eye lens capsules. The lens capsule is a transparent membrane that surrounds the entire lens.
This junction marks the transition from the simple, non-photosensitive area of the ciliary body to the complex, multi-layered, photosensitive region of the retina. The pigmented layer is continuous over choroid, ciliary body and iris while the nervous layer terminates just before the ciliary body. This point is the ora serrata.
The block in flow of aqueous from the posterior to the anterior chamber will lead to a condition known as Iris bombe. In this condition, pressure in the posterior chamber rises, resulting in anterior bowing of the peripheral iris and obstruction of the trabecular meshwork. This may result in an acute attack of angle closure glaucoma. [5]