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Vitreous Chamber
The vitreous chamber is the space in the eye occupied by vitreous humor. Structure Within the vertebrate eye, there are considered to be three chambers: anterior, posterior, and vitreous. It is important to note that the eye can also be classified as having two cavities: anterior and posterior. Both the anterior and posterior chambers are located within the anterior cavity, while the vitreous chamber is located in the posterior cavity. The best way to distinguish between the two cavities is to use the lens as a dividing point. The vitreous chamber is the largest of the three chambers and is located behind the lens and in front of the optic nerve. This chamber is filled with a thick, clear gel-like substance called the vitreous humor (also vitreous body). The humor plays a crucial role in supporting the posterior side of the lens. Function The vitreous fluid, along with supporting the lens, also functions in maintaining the shape of the entire vitreous chamber and posterior cavi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Eye
The human eye is a sensory organ, part of the sensory nervous system, that reacts to visible light and allows humans to use visual information for various purposes including seeing things, keeping balance, and maintaining circadian rhythm. The eye can be considered as a living optical device. It is approximately spherical in shape, with its outer layers, such as the outermost, white part of the eye (the sclera) and one of its inner layers (the pigmented choroid) keeping the eye essentially light tight except on the eye's optic axis. In order, along the optic axis, the optical components consist of a first lens (the cornea—the clear part of the eye) that accomplishes most of the focussing of light from the outside world; then an aperture (the pupil) in a diaphragm (the iris—the coloured part of the eye) that controls the amount of light entering the interior of the eye; then another lens (the crystalline lens) that accomplishes the remaining focussing of light into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitreous Humor
The vitreous body (''vitreous'' meaning "glass-like"; , ) is the clear gel that fills the space between the lens and the retina of the eyeball (the vitreous chamber) in humans and other vertebrates. It is often referred to as the vitreous humor (also spelled humour, from Latin meaning liquid) or simply "the vitreous". Vitreous fluid or "liquid vitreous" is the liquid component of the vitreous gel, found after a vitreous detachment. It is not to be confused with the aqueous humor, the other fluid in the eye that is found between the cornea and lens. Structure The vitreous humor is a transparent, colorless, gelatinous mass that fills the space in the eye between the lens and the retina. It is surrounded by a layer of collagen called the vitreous membrane (or hyaloid membrane or vitreous cortex) separating it from the rest of the eye. It makes up four-fifths of the volume of the eyeball. The vitreous humour is fluid-like near the centre, and gel-like near the edges. The vitreous hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterior Chamber Of Eyeball
The anterior chamber (Optometric Abbreviations#AC, AC) is the aqueous humor-filled space inside the human eye, eye between the iris (anatomy), iris and the cornea's innermost surface, the Corneal endothelium, endothelium. Hyphema, Uveitis, anterior uveitis and glaucoma are three main pathologies in this area. In hyphema, blood fills the anterior chamber as a result of a hemorrhage, most commonly after a blunt eye injury. Anterior uveitis is an inflammatory process affecting the iris (anatomy), iris and ciliary body, with resulting inflammatory signs in the anterior chamber. In glaucoma, blockage of the trabecular meshwork prevents the normal outflow of aqueous humour, resulting in increased intraocular pressure, progressive damage to the optic nerve head, and eventually blindness. The depth of the anterior chamber of the eye varies between 1.5 and 4.0 mm, averaging 3.0 mm. It tends to become shallower at older age and in eyes with Far-sightedness, hypermetropia (far sight ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posterior Chamber Of Eyeball
The posterior chamber is a narrow space behind the peripheral part of the iris, and in front of the suspensory ligament of the lens and the ciliary processes. The posterior chamber consists of small space directly posterior to the iris but anterior to the lens. The posterior chamber is part of the anterior segment and should not be confused with the vitreous chamber (in the posterior segment). Posterior chamber is an important structure involved in production and circulation of aqueous humor. Aqueous humor produced by the epithelium of the ciliary body is secreted into the posterior chamber, from which it flows through the pupil to enter the anterior chamber. The hypermature cataractous lens or, the intraocular lens implanted after cataract surgery may obstruct the aqueous flow through the pupil. 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, resul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterior Segment Of Eyeball
The anterior segment or anterior cavity is the front third of the eye that includes the structures in front of the vitreous humour: the cornea, iris, ciliary body, and lens.Cassin, B. and Solomon, S. ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company, 1990."Departments. Anterior segment." Cantabrian Institute of Ophthalmology. Within the anterior segment are two fluid-filled spaces: * the between the posterior surface of the cornea (i.e. the ) and the iris. * the [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posterior Segment Of Eyeball
The posterior segment or posterior cavity is the back two-thirds of the eye that includes the anterior hyaloid membrane and all of the optical structures behind it: the vitreous humor, retina, choroid, and optic nerve.Posterior segment anatomy The portion of the posterior segment visible during (or fundoscopy) is sometimes referred to as the , or fundus. Some op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lens (anatomy)
The lens, or crystalline lens, is a transparent biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. By changing shape, it functions to change the focal length of the eye so that it can focus on objects at various distances, thus allowing a sharp real image of the object of interest to be formed on the retina. This adjustment of the lens is known as '' accommodation'' (see also below). Accommodation is similar to the focusing of a photographic camera via movement of its lenses. The lens is flatter on its anterior side than on its posterior side. In humans, the refractive power of the lens in its natural environment is approximately 18 dioptres, roughly one-third of the eye's total power. Structure The lens is part of the anterior segment of the human eye. In front of the lens is the iris, which regulates the amount of light entering into the eye. The lens is suspended in place by the suspensory ligament of the lens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retina
The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then processes that image within the retina and sends nerve impulses along the optic nerve to the visual cortex to create visual perception. The retina serves a function which is in many ways analogous to that of the film or image sensor in a camera. The neural retina consists of several layers of neurons interconnected by synapses and is supported by an outer layer of pigmented epithelial cells. The primary light-sensing cells in the retina are the photoreceptor cells, which are of two types: rods and cones. Rods function mainly in dim light and provide monochromatic vision. Cones function in well-lit conditions and are responsible for the perception of colour through the use of a range of opsins, as well as high-acuity vision used for task ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitreous Humor
The vitreous body (''vitreous'' meaning "glass-like"; , ) is the clear gel that fills the space between the lens and the retina of the eyeball (the vitreous chamber) in humans and other vertebrates. It is often referred to as the vitreous humor (also spelled humour, from Latin meaning liquid) or simply "the vitreous". Vitreous fluid or "liquid vitreous" is the liquid component of the vitreous gel, found after a vitreous detachment. It is not to be confused with the aqueous humor, the other fluid in the eye that is found between the cornea and lens. Structure The vitreous humor is a transparent, colorless, gelatinous mass that fills the space in the eye between the lens and the retina. It is surrounded by a layer of collagen called the vitreous membrane (or hyaloid membrane or vitreous cortex) separating it from the rest of the eye. It makes up four-fifths of the volume of the eyeball. The vitreous humour is fluid-like near the centre, and gel-like near the edges. The vitreous hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitreous Detachment
A posterior vitreous detachment (PVD) is a condition of the eye in which the vitreous membrane separates from the retina. It refers to the separation of the posterior hyaloid membrane from the retina anywhere posterior to the vitreous base (a 3–4 mm wide attachment to the ora serrata). The condition is common for older adults; over 75% of those over the age of 65 develop it. Although less common among people in their 40s or 50s, the condition is not rare for those individuals. Some research has found that the condition is more common among women. Symptoms When this occurs there is a characteristic pattern of symptoms: * Flashes of light (photopsia) * A sudden dramatic increase in the number of floaters * A ring of floaters or hairs just to the temporal side of the central vision As a posterior vitreous detachment proceeds, adherent vitreous membrane may pull on the retina. While there are no pain fibers in the retina, vitreous traction may stimulate the retina, with r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aqueous Humor
The aqueous humour is a transparent water-like fluid similar to plasma, but containing low protein concentrations. It is secreted from the ciliary body, a structure supporting the lens of the eyeball. It fills both the anterior and the posterior chambers of the eye, and is not to be confused with the vitreous humour, which is located in the space between the lens and the retina, also known as the posterior cavity or vitreous chamber. Blood cannot normally enter the eyeball. Structure Composition *Amino acids: transported by ciliary muscles *98% water *Electrolytes ( pH = 7.4 -one source gives 7.1) **Sodium = 142.09 **Potassium = 2.2 - 4.0 **Calcium = 1.8 **Magnesium = 1.1 **Chloride = 131.6 **HCO3- = 20.15 **Phosphate = 0.62 ** Osm = 304 *Ascorbic acid *Glutathione *Immunoglobulins Function *Maintains the intraocular pressure and inflates the globe of the eye. It is this hydrostatic pressure that keeps the eyeball in a roughly spherical shape and keeps the walls of the eyeball ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
