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The iris and ciliary body together are known as the anterior uvea. Just in front of the root of the iris is the region referred to as the trabecular meshwork, through which the aqueous humour constantly drains out of the eye, with the result that diseases of the iris often have important effects on intraocular pressure and indirectly on vision ...
Iris is a flowering plant genus of 310 accepted species [1] with showy flowers.As well as being the scientific name, iris is also widely used as a common name for all Iris species, as well as some belonging to other closely related genera.
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. Structure of the iris and surrounding parts showing the stroma of iris (stroma iridis).
The uvea (/ ˈ j uː v i ə /; [1] derived from Latin: uva meaning "grape"), also called the uveal layer, uveal coat, uveal tract, vascular tunic or vascular layer, is the pigmented middle layer of the three concentric layers that make up an eye, precisely between the inner retina and the outer fibrous layer composed of the sclera and cornea.
When viewed at large angles from the side, the iris and pupil may still be visible by the viewer, indicating the person has peripheral vision possible at that angle. [ 15 ] [ 16 ] [ 17 ] About 15° temporal and 1.5° below the horizontal is the blind spot created by the optic nerve nasally, which is roughly 7.5° high and 5.5° wide.
The short ciliary nerves contain both parasympathetic and sympathetic nerve fibers. The parasympathetic fibers arise from the Edinger-Westphal nucleus and synapse in the ciliary ganglion via the oculomotor nerve, the postganglionic parasympathetics leave the ciliary ganglion in the short ciliary nerve and supply the ciliary body and iris.
Along with the ciliary body and iris, the choroid forms the uveal tract. The structure of the choroid is generally divided into four layers (classified in order of furthest away from the retina to closest): Haller's layer – outermost layer of the choroid consisting of larger diameter blood vessels; [1]
Open-angle glaucoma (OAG) and closed-angle glaucoma (CAG) may be treated by muscarinic receptor agonists (e.g., pilocarpine), which cause rapid miosis and contraction of the ciliary muscles, this pulls the scleral spur and results in the trabecular meshwork being stretched and separated.