Search results
Results from the WOW.Com Content Network
Visual or vision impairment (VI or VIP) is the partial or total inability of visual perception.In the absence of treatment such as corrective eyewear, assistive devices, and medical treatment, visual impairment may cause the individual difficulties with normal daily tasks, including reading and walking. [6]
Color blindness affects a large number of individuals, with protans and deutans being the most common types. [36] In individuals with Northern European ancestry, as many as 8 percent of men and 0.4 percent of women experience congenital color deficiency. [68] [69] Interestingly, even Dalton's first paper already arrived upon this 8% number: [70]
Congenital red–green color blindness affects a large number of individuals, especially individuals of European ancestry, where 8% of men and 0.4% of women exhibit congenital red–green color deficiency. [19] The lower prevalence in females is related to the x-linked inheritance of congenital red–green color blindness, as explained above.
Cortical blindness refers to any partial or complete visual deficit that is caused by damage to the visual cortex in the occipital lobe. Unilateral lesions can lead to homonymous hemianopias and scotomas. Bilateral lesions can cause complete cortical blindness and can sometimes be accompanied by a condition called Anton-Babinski syndrome. [26]
It was estimated by the WHO in 2004 that 314 million people worldwide are vision impaired (from all causes), of whom 45 million are blind. [14] Vision disorders are not often targeted by public health initiatives, as mortality causes take priority. [ 15 ]
People with RM have a reduced visual acuity, (usually about 0.1 or 20/200), have total color blindness, photo-aversion and nystagmus. The nystagmus and photo-aversion usually are present during the first months of life, and the prevalence of the disease is estimated to be 1 in 30,000 worldwide. [ 3 ]
Leber's congenital amaurosis (LCA) is a collection of inherited, degenerative eye disorders that can reduce the strength of visual clarity or sharpness in infants and can cause childhood blindness. [ 14 ] [ 15 ] These eye disorders are mostly autosomal recessive diseases, and diagnoses of LCA are linked to multiple gene variants, including the ...
Choroideremia (/ k ɒ ˌ r ɔɪ d ɪ ˈ r iː m i ə /; CHM) is a rare, X-linked recessive form of hereditary retinal degeneration that affects roughly 1 in 50,000 males. The disease causes a gradual loss of vision, starting with childhood night blindness, followed by peripheral vision loss and progressing to loss of central vision later in life.