Posts Tagged ‘diabetic retinopathy’
Good vision such as 20/20 does not mean satisfying contrast sensitivity. Common vision tests using black letters or numbers displayed against white backgrounds can not reflect your exact contrast sensitivity, since the real world is filled with grey shades. So that special contrast sensitivity testing is necessary.
May eye diseases or conditions may cause poor contrast sensitivity, such as cataracts, glaucoma, and diabetic retinopathy, as well as the side effects from LASIK and PRK. People with low contrast sensitivity may have difficulty in some conditions, such as seeing traffic lights, spot other cars and pedestrians during night driving. Since these people have poor perception of objects that do not stand out from their backgrounds, they may even stumble when they fail to see similarly colored pavements.
The term “contrast sensitivity function” (CSF) is used to describe people’s low contrast seeing ability. A contrast sensitivity test may be included in a routine screening after the visual acuity test, which measures the ability of seeing detailed letters or numbers. With your plastic eyeglasses or contacts lenses wearing on, your eyes will be tested in together by a low-contrast test chart, which consists of bars and dots in different colored contrasts that are used to evaluate the patient’s exact CSF. Your CSF will certainly be affected by the sizes of objects: the larger the objects are, the higher CSF you can achieve.
By testing your eyes using bar and dot patterns displayed against varying contacts or intensities, your highest and lowest contrast sensitivity can be determined and plotted into a curve, which shows your contrast sensitivity readings. Tests under both bright and dark conditions can provide more detailed information about your images process capability.
As a volunteer, you can get a contrast sensitivity test as a necessary part of the evaluation of new ophthalmic devices such as LASIK excimer lasers and new intraocular lenses required by FDA. Once you are diagnosed with low contrast sensitivity, some remedies are available, depending on the source of the problem. Usually, artificial lenses with a yellow filter can improve contrast. If the low contrast sensitivity is caused by higher-order aberrations, wavefront lenses or LASIK are the right choices. Another option is intraocular lenses with yellow tints, which can also offset low contrast sensitivity.
Article Source:http://vision.firmoo.com/eye-exams/low-contrast-sensitivity-tests-and-treatments.html
Vision Library is the information source in area of vision care, including eyeglasses, sunglasses, contact lenses, sports protective eyewear, vision error and diseases, vision surgery, ageing and kid’s vision etc., solely sponsored by Firmoo.com, an emerging online optical store offering high quality eyewear at the lowest prices.Firmoo’s return and refund policy make any purchase risk-free.
Article Source:http://www.articlesbase.com/vision-articles/low-contrast-sensitivity-tests-and-treatments-1408662.html
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Blurred vision is the lack of sharpness of vision and symptoms of not being able to see fine things, also called vision impairment, impaired vision, blurry vision. Blurred vision can be caused by many different conditions. Blurry vision occurs when a person who wears corrective lens, abnormalities present at birth, overexposure to the outdoors or a side effect of medications. Presbyopia can result in blurry vision too, mostly in your early to mid 40. Eye infection or injury may lead to blurred vision briefly. Cataracts always cause blurred vision, especially at nighttime. Glaucoma is another reason for blurred vision, which may happen suddenly. Macular degeneration can cause the loss of central vision, blurred vision and distorted vision. Diabetic retinopathy can not only lead to blurry vision but also blindness.
Blurred vision should not be ignored, because blurred vision can be the important clue to eye disease, aging, eye injury, retinal detachment or other conditions such as migraine, diabetes or stoke. When you find yourself of blurry vision, you should visit your eye doctor for an eye care. Treatments or surgery will be depending on the cause of blurry vision.
In order to avoid blurred vision, make sure to do eye checkups from an ophthalmologist or optometris every year or half year. And daily habbits such as semi rimless eyeglasses, no smoking, keep blood pressure and blood sugar under control, eat green leafy vegetables are also effective to pretect you from blurry vision.
Article Source: http://blog.firmoo.com/keep-away-from-blurred-vision.html
Vision Library is the information source in area of vision care, including eyeglasses, sunglasses, contact lenses, sports protective eyewear, vision error and diseases, vision surgery, ageing and kid’s vision etc., solely sponsored by Firmoo.com, an emerging online optical store offering high quality eyewear at the lowest prices.Firmoo’s return and refund policy make any purchase risk-free.
Article Source:http://www.articlesbase.com/vision-articles/keep-away-from-blurred-vision-1367574.html
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What happens after you’ve hired that qualified person who is blind or low vision? Very often co-workers and supervisors have questions that center around wondering, “How do I work with him? How can I talk with her? What do I need to do differently?”
Blindness means that an individual has 10% or less of normal vision (80% of those who are legally blind have some degree of vision while 20% have none.) Low vision is a visual impairment, not correctable by standard glasses, contact lenses, medicine, or surgery, that interferes with the ability to perform everyday activities. Most people develop low vision because of eye disease such as cataracts, glaucoma, diabetic retinopathy or macular degeneration. Low Vision primarily affects people over the age of 65. macular degeneration products are widely available due to increasing aging population. Yes, for some workers who are legally blind, some tasks will be done using sight. This can get confusing if co-workers or supervisors believe only “total blindness” fits the definition of “blind” and it can lead to misunderstandings.
For example, a saleswoman in a department store in New Jersey is doing all necessary tasks well using her sight along with some low vision aids, with one exception. She physically cannot read numbers on products for inventory purposes. Her immediate supervisor thought she was malingering and “gave her a hard time” until he understood the parameters on her vision loss. He appreciated her understanding that he just needed the facts. Now during inventory, when the work is divided among the associates, she is given a necessary task that fits her strengths. The low vision aids, although not a complete solution, makes the saleswoman competitive.
Among those blind persons who have some sight, a few will read print, but will not have the ability to see people coming toward them on the other side of a hallway (“tunnel vision” or loss of field); some have “night blindness” but function with sighted techniques when there is enough light without glare; some will see general shapes and colors, or that lights are on. Some are totally blind and use blind techniques all of the time. There are other variations.
What matters is not how much sight is left but the amount of skill the blind person has in using blind techniques when sighted techniques won’t produce work on time, to the competitive level. A practical definition of blindness could be stated like this:
You are blind if you find it more efficient, some or all of the time, to use blind techniques rather than sighted techniques to perform tasks to a competitive level.
There are two suggestions that are likely to fit every case. First, it often helps blind colleagues if you verbalize. (For instance, don’t just point, say, “It’s on the left.”) Second, start with the assumption that the other adult is as competent as you are.
How to get more information on low vision products – Ask your Eye MD for a Low vision or Blindness Specialist. Low vision specialists are licensed doctors of optometry who are trained in the examination and management of patients with visual impairments. A few of them are ophthalmologists with additional training in low vision care. Their services do not offer a cure for the causes of low vision, but they do help the patient learn how to utilize their remaining vision to its fullest potential. Low vision care does not replace the possible need for other treatments such as laser, medication, and surgery.
Low Vision Specialist – Low Vision Technology
Article Source:http://www.articlesbase.com/vision-articles/blindness-low-vision-at-work-1125013.html