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Human ocular prosthesis of brown color. Cat with an ocular prosthesis. An ocular prosthesis, artificial eye or glass eye is a type of craniofacial prosthesis that replaces an absent natural eye following an enucleation, evisceration, or orbital exenteration.
Its prevalence in different human populations varies; for example, it is prevalent in Scandinavia. [2] The buildup of protein clumps can block normal drainage of the eye fluid called the aqueous humor and can cause, in turn, a buildup of pressure leading to glaucoma and loss of vision [3] (pseudoexfoliation glaucoma, exfoliation glaucoma). As ...
The affected eye may be hyperpigmented (hyperchromic) or hypopigmented (hypochromic). [3] In humans, an increase of melanin production in the eyes indicates hyperplasia of the iris tissues, whereas a lack of melanin indicates hypoplasia. The term is derived from Ancient Greek: ἕτερος, héteros "different" and χρῶμα, chrôma "color ...
To avoid a sunken appearance to the eye socket, an implant approximating this volume can be placed into the space of the removed eye, secured, and covered with Tenon's capsule and conjunctiva. [7] Implants can be made of many materials with the most common being hydroxylapatite , metal alloy, [ 8 ] acrylic, or glass.
On photographs taken using a flash, instead of the familiar red-eye effect, leukocoria can cause a bright white reflection in an affected eye. Leukocoria may appear also in low indirect light, similar to eyeshine. Leukocoria can be detected by a routine eye exam (see Ophthalmoscopy). For screening purposes, the red reflex test is used.
There is evidence that as many as 16 different genes could be responsible for eye color in humans; however, the main two genes associated with eye color variation are OCA2 and HERC2, and both are localized in chromosome 15. [10] The gene OCA2 (OMIM: 203200), when in a variant form, causes the pink eye color and hypopigmentation common in human ...
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Human vision relies on a duplex retina, comprising two types of photoreceptor cells. Rods are primarily responsible for dim-light scotopic vision and cones are primarily responsible for day-light photopic vision. For all known vertebrates, scotopic vision is monochromatic, since there is typically only one class of rod cell.