| Low vision is a subspecialty within the professions of optometry, ophthalmology and opticianry dealing with individuals who have less than normal vision even with the most accurate conventional prescription available. It can be a result of either congenital or acquired factors; anyone with non‐correctable reduced vision is considered to be visually impaired, and can have a wide range of causes. There are also levels of visual impairment based on visual field loss (loss of peripheral vision). In the United States, any person with vision that cannot be corrected to better than 20/200 in the best eye, or who has 20 degrees (diameter) or less of visual field remaining, is considered to be "legally blind" or eligible for disability classification and possible inclusion in certain government sponsored programs.
Globally, in 2002 more than 161 million people were visually impaired, of whom 124 million people had low vision and 37 million were blind. However, refractive error as a cause of visual impairment was not included, which implies that the actual global magnitude of visual impairment is greater. There are many different causes of Low Vision; some of the ailments are Cataracts, Glaucoma, Uveitis, Macular degeneration, Corneal opacity, Trachoma, Diabetic retinopathy, Myopia magna, Stargardt's disease, Albinism and Retinitis pigmentosa.
There are several devices and treatments designed to improve the various types of Low Vision issues, however improving sensitivity to contrast requires the person to use special optical filters. Low Vision Cocoons are available in four of the most prescribed tints Boysenberry (plum), Lemon (yellow), Hazelnut (amber) and Orange. Each tint is specifically designed to absorb different amounts of the visible light spectrum. For example, a patient may respond best to the reduction or elimination of scattered Blue Light. Blue light that enters the retina creates distortion by making the definition of objects not as crisp; our Hazelnut and Orange lenses are extremely effective for blocking blue light.
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The Lemon lens, sometimes referred to as Yellow, provides moderate blue light filtering, which is ideal for reading and watching television. Lemon provides 82% light transmission and blocks 100% UVA/UVB light and all visible light up to 450nm. It helps increase contrast indoors, but should not really be used outside in direct sunlight. It’s a tint that is better for low light conditions, unless specifically ordered for outdoor use by a Low Vision specialist.
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