Albinism history and symptoms: Difference between revisions
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[[Image:Albinistic girl papua new guinea.jpg|thumb|left|240px|Albinistic girl from [[Papua New Guinea]]]] | [[Image:Albinistic girl papua new guinea.jpg|thumb|left|240px|Albinistic girl from [[Papua New Guinea]]]] | ||
Organisms with albinism usually have impaired vision due to one or more of the listed conditions. While a person with albinism may suffer from common refractive errors like nearsightedness or farsightedness, the visual problems particularly associated with albinism arise from a poorly-developed [[retinal pigment epithelium]] (RPE) due to the lack of melanin {{Fact|date=February 2007}}. This degenerate RPE causes foveal [[hypoplasia]] (a failure in the development of normal [[fovea]]e), which results in eccentric fixation and lower visual acuity, and often a minor level of strabismus. Nystagmus is usually seen, as is [[photophobia]] or light sensitivity (see below). | Organisms with albinism usually have impaired vision due to one or more of the listed conditions. While a person with albinism may suffer from common refractive errors like nearsightedness or farsightedness, the visual problems particularly associated with albinism arise from a poorly-developed [[retinal pigment epithelium]] (RPE) due to the lack of melanin {{Fact|date=February 2007}}. This degenerate RPE causes foveal [[hypoplasia]] (a failure in the development of normal [[fovea]]e), which results in eccentric fixation and lower visual acuity, and often a minor level of strabismus. Nystagmus is usually seen, as is [[photophobia]] or light sensitivity (see below). | ||
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The lack of pigment also makes the skin unusually sensitive to sunlight and thus susceptible to [[sunburn]], so people with albinism should either avoid prolonged exposure to bright sunlight or protect their skin. | The lack of pigment also makes the skin unusually sensitive to sunlight and thus susceptible to [[sunburn]], so people with albinism should either avoid prolonged exposure to bright sunlight or protect their skin. | ||
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Overview
Symptoms and conditions associated with albinism
Genetic testing can confirm albinism and what variety it is, but offers no medical benefits except in the cases of non-OCA disorders (see below) that cause albinism along with other medical problems which may be treatable. The symptoms of albinism can be treated by various methods detailed below.
Eye conditions common in albinism may include:
- Nystagmus, irregular rapid movement of the eyes back and forth, or in circular motion.
- Strabismus, eye misalignment ("crossed eyes" or "lazy eye").
- Refractive errors such as myopia or hyperopia and especially astigmatism are more likely[1]
- Photophobia, hypersensitivity to bright light and glare.
- Foveal hypoplasia, underdevelopment of the fovea, the center of the retina
- Optic nerve hypoplasia, underdevelopment of the optic nerve
- Abnormal decussation (crossing) of the optic nerve fibers in the optic chiasm[2]
- Amblyopia, decrease in acuity of one or both eyes due to poor transmission to the brain, often due to other conditions such as strabismus
Organisms with albinism usually have impaired vision due to one or more of the listed conditions. While a person with albinism may suffer from common refractive errors like nearsightedness or farsightedness, the visual problems particularly associated with albinism arise from a poorly-developed retinal pigment epithelium (RPE) due to the lack of melanin[citation needed]. This degenerate RPE causes foveal hypoplasia (a failure in the development of normal foveae), which results in eccentric fixation and lower visual acuity, and often a minor level of strabismus. Nystagmus is usually seen, as is photophobia or light sensitivity (see below). The iris is a sphincter with pigmented tissue (which makes up the color of the eyes) that contracts to limit the amount of light that can enter through the pupil and relaxes again to allow for better vision in darkness. This mechanism can be observed in humans and mammals (like in cat's eyes) and is needed because too much light is uncomfortable or even painful and decreases vision. In people with albinism, the iris does not have enough pigment to block the light, thus the decrease of pupil diameter is only partially successful in reducing the amount of light that enters the eye.[citation needed]. Additionally, the improper development of the RPE, which in normal eyes absorbs most of the reflected sunlight, further increases glare due to light scattering within the eye.[2] The resulting sensitivity (photophobia) generally leads to a dislike of and discomfort in bright light, but does not prevent people with albinism enjoying the outdoors, especially when using sunglasses and/or brimmed hats.[3]
The lack of pigment also makes the skin unusually sensitive to sunlight and thus susceptible to sunburn, so people with albinism should either avoid prolonged exposure to bright sunlight or protect their skin.
References
- ↑ "Albinism: Modern molecular diagnosis"
- ↑ 2.0 2.1 "Albinism - Review of Optometry Online"
- ↑ "Facts about Albinism", by Dr. Richard King et al.