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The bony area that makes up the human eye socket provides exceptional protection to the sclera. However, if the sclera is ruptured by a blunt force or is penetrated by a sharp object, the recovery of full former vision is usually rare. If pressure is applied slowly, the eye is actually very elastic.
An area termed the limbus connects the cornea and sclera. The iris is the pigmented circular structure concentrically surrounding the centre of the eye, the pupil, which appears to be black. The size of the pupil, which controls the amount of light entering the eye, is adjusted by the iris' dilator and sphincter muscles .
The fovea centralis is a small, central pit composed of closely packed cones in the eye.It is located in the center of the macula lutea of the retina. [1] [2]The fovea is responsible for sharp central vision (also called foveal vision), which is necessary in humans for activities for which visual detail is of primary importance, such as reading and driving.
The visual system is the physiological basis of visual perception (the ability to detect and process light).The system detects, transduces and interprets information concerning light within the visible range to construct an image and build a mental model of the surrounding environment.
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.
Schlemm's canal, also known as the canal of Schlemm, and as the scleral venous sinus, is a circular lymphatic-like vessel in the eye. It collects aqueous humor from the anterior chamber and delivers it into the episcleral blood vessels. Canaloplasty may be used to widen it.
The vascular tunic, also known as the tunica vasculosa oculi or the "uvea", is the middle vascularized layer which includes the iris, ciliary body, and choroid. [ 4 ] [ 6 ] [ 7 ] The choroid contains blood vessels that supply the retinal cells with necessary oxygen and remove the waste products of respiration .
Because the aperture of an eyelet is larger than the facets of a compound eye, this arrangement allows vision under low light levels. [1] Good fliers such as flies or honey bees, or prey-catching insects such as praying mantis or dragonflies, have specialised zones of ommatidia organised into a fovea area which gives acute vision. In the acute ...