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The main function of crystallins at least in the lens of the eye is probably to increase the refractive index while not obstructing light. However, this is not their only function. It has become clear that crystallins may have several metabolic and regulatory functions, both within the lens and in other parts of the body. [7]
Vision of humans and other organisms depends on several organs such as the lens of the eye, and any vision correcting devices, which use optics to focus the image. The eyes of many animals contains a lens that focuses the light of its surroundings onto the retina of the eye. This lens is essential to producing clear images within the eye.
With vision in fish and amphibians, the lens is fixed in shape, and focusing is instead achieved by moving the lens forwards or backwards within the eye using a muscle called the retractor lentus. [54] In cartilaginous fish, the suspensory ligaments are replaced by a membrane, including a small muscle at the underside of the lens. This muscle ...
Ultra-high temperature processing (UHT), ultra-heat treatment, or ultra-pasteurization [1] is a food processing technology that sterilizes liquid food by heating it above 140 °C (284 °F) – the temperature required to kill bacterial endospores – for two to five seconds. [2]
Absence of lens: Congenital or acquired aphakia cause high degree hypermetropia. [13] Far-sightedness is often present from birth, but children have a very flexible eye lens, which helps to compensate. [14] In rare instances, hyperopia can be due to diabetes, as well as problems with the blood vessels in the retina. [1]
There are some exceptions from the types mentioned above. Some insects have a so-called single lens compound eye, a transitional type which is something between a superposition type of the multi-lens compound eye and the single lens eye found in animals with simple eyes. Then there is the mysid shrimp, Dioptromysis paucispinosa. The shrimp has ...
An intraocular lens (IOL) is a lens implanted in the eye usually as part of a treatment for cataracts or for correcting other vision problems such as near-sightedness (myopia) and far-sightedness (hyperopia); a form of refractive surgery.
Long-term contact lens use can lead to alterations in corneal thickness, stromal thickness, curvature, corneal sensitivity, cell density, and epithelial oxygen uptake. . Other structural changes may include the formation of epithelial vacuoles and microcysts (containing cellular debris), corneal neovascularization, as well as the emergence of polymegethism in the corneal endoth