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Prescription Lenses
Obtaining a correct prescription from your doctor
is the first important step in seeing well, but not the last. Selecting
the right lenses for your glasses is a critical and yet poorly understood
factor. This is especially true for seniors, patients who spend
lots of time on computers, sports enthusiasts and those with certain
eye diseases.
Seniors aged 65 need about six times the amount
of light to see as well as a twenty year old due to various changes
in the cornea, lens and retina. A normal untreated plastic lens
loses about 8% of light due to reflections and a high-index lens
loses about 12%. The only way to combat this loss of light is with
anti-reflective (AR) coats, which increase transmission to about
99%. The best AR coats have built-in warranted scratch coats, which
provide a type of insurance on the lenses against scratching. Seniors
are also more sensitive to glare, which may be annoying or incapacitating.
This problem is dealt with by utilizing photochromic lenses that
change color or with separate polarized sunglasses. Even the color
of the tint will affect the vision in different environments.
Computer users face many special visual demands.
Those with moderate computer use will often find one of the better
progressive lenses works adequately. Less expensive progressives
are not recommended because the clear zones tend to be too narrow
for comfort. Those who put in long hours on the computer often find
greatly improved visual comfort with a pair of glasses designed
exclusively for computer use. This usually results in the best vision
and comfort.
Sports enthusiasts also face unique sets of visual
demands. Most tend to do well with the AR coats because of the increased
light transmission. When glare is an issue, such as skiing, on the
water or biking on roadways, glare-blocking polarized lenses are
a must. The differing demands of golf, tennis, shooting sports and
water sports all have specific colored tints that are used to enhance
performance.
Finally, different eye diseases are made worse
by certain wavelengths of light, requiring tints or UV protection.
Cataracts and macular degeneration are of the most common such conditions.
As you see above, the correct prescription
focuses your vision well, but other lens considerations can make
a significant difference. AR coats, polarizing lenses and selected
tints can make the difference between “OK” and GREAT!
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