Advertisement




More DailyStrength
Health Event Calendar
See what's new on the site
Step-by-step Tutorials
How to use DailyStrength
We're on Facebook
Check out our page
Follow us on Twitter
Read our tweets
Get Cool DS Stuff
Shirts, Hats, Baby Wear

Blindness & Visual Impairment Information

  • Blindness is the condition of lacking visual perception due to physiological or psychological factors. Various scales have been developed to describe the extent of vision loss and define "blindness". Total blindness is the complete lack of form and light perception and is clinically recorded as "NLP", an abbreviation for "no light perception". "Blindness" is frequently used to describe severe visual impairment with residual vision...
  • In order to determine which people may need special assistance because of their visual disabilities, various governmental jurisdictions have formulated more complex definitions referred to as legal blindess. In North America and most of Europe, legal blindness is defined as visual acuity (vision) of 20/200 (6/60) or less in the better eye with best correction possible. This means that a legally blind individual would have to stand 20 feet from an object to see it with the same degree of clarity as a normally sighted person could from 200 feet. In many areas, people with average acuity who nonetheless have a visual field of less than 20 degrees (the norm being 180 degrees) are also classified as being legally blind. Approximately ten percent of those deemed legally blind, by any measure, are fully sightless. The rest have some vision, from light perception alone to relatively good acuity. Those who are not legally blind, but nonetheless have serious visual impairments, possess low vision.

    Serious visual impairment has a variety of causes:

    Most visual impairment is caused by disease and malnutrition. According to WHO estimates in 2002, the most common causes of blindness around the world are: cataracts (47.8%), glaucoma (12.3%), age-related macular degeneration (AMD) (8.7%), trachoma (3.6%), corneal opacity (5.1%), and diabetic retinopathy (4.8%), among other causes.

    People in developing countries are significantly more likely to experience visual impairment as a consequence of treatable or preventable conditions than are their counterparts in the developed world. While vision impairment is most common in people over age 60 across all regions, children in poorer communities are more likely to be affected by blinding diseases than are their more affluent peers.

    The link between poverty and treatable visual impairment is most obvious when conducting regional comparisons of cause. Most adult visual impairment in North America and Western Europe is related to age-related macular degeneration and diabetic retinopathy. While both of these conditions are subject to treatment, neither can be cured.

    In developing countries, wherein people have shorter life expectancies, cataracts and water-borne parasites-both of which can be treated effectively-are most often the culprits. Of the estimated 40 million blind people located around the world, 70-80% can have some or all of their sight restored through treatment.

    In developed countries where parasitic diseases are less common and cataract surgery is more available, age-related macular degeneration, glaucoma, and diabetic retinopathy are usually the leading causes of blindness.

    Eye injuries, most often occurring in people under 30, are the leading cause of monocular blindness (vision loss in one eye) throughout the United States. Injuries and cataracts affect the eye itself, while abnormalities such as optic nerve hypoplasia affect the nerve bundle that sends signals from the eye to the back of the brain, which can lead to decreased visual acuity.

    People with injuries to the occipital lobe of the brain can, despite having undamaged eyes and optic nerves, still be legally or totally blind.

    People with albinism often suffer from visual impairment to the extent that many are legally blind, though few of them actually cannot see.

    Recent advances in mapping the human genome have identified other genetic causes of low vision or blindness. One such example is Bardet-Biedl syndrome.

    A small portion of all cases of blindness are caused by the intake of certain chemicals. A well-known example is Methanol, which is sometimes used by alcoholics as a cheap substitute or addition to the less toxic Ethanol in alcoholic beverages.

  • Click to expand

Health Blogs

Paula Deen’s show and cookbooks are heavily laden with fat, rich cream, bacon, meats, and cheesy pastas. Should we be surprised that she has adult onset diabetes? No. Should we feel weird that she knew it for three years, did her cooking show without mention of lower carb options or the importance of eating that stuff in moderation? Maybe. Is it ... Read More »
From wine to jelly to raisins, grapes can be enjoyed in a number of ways. So it's no wonder that grapes are the second-most popular fruit (they come in a close second to oranges) and that growing and processing grapes is one of the world’s largest food industries. One of the earliest cultivated fruits, grapes were introduced in biblical ... Read More »
A rather interesting but concerning study to be published in next month’s issue of Pediatrics found the prevalence of children with developmental disabilities increased by 17% between 1997 and 2008... a number which translates to nearly 10 million of U.S. children in 2008 having a developmental disability. The CDC used data from the ... Read More »

Member Photos

Advertisement

Latest Activity