The world
has been revolutionizing and so is the eyeglass industry which has given birth
to wide variety of lens.There used to be a time when spectacles had only one
lens power, but now the things have changed; technology has revamped things to
a new level.
Now there
are different forms of multi-focal
lens that helps in solving many vision problems at once. Although multi-focal lens is prescribed to adults over age 40 as they have a refractive error of
Presbyopia; eyes cannot naturally focus on near and distant objects.
Eye Glasses with two or more lens power helps in correcting different
vision problems in one go instead of switching spectacles again and again for
different activities.
Here we will
analyze different forms of lens.
1. Bifocal Lens
Bifocals
have two lens power for correcting both, farsightedness (hyperopia) and
nearsightedness (myopia), vision problems at one time.
These lens
actually have two segments, upper segment and lower segment.The upper segment
helps in focusing on objects that are in distance while the lower segment helps
in focusing on objects that are near. However, the lower segment for near
vision is usually a small proportion of the lens but it can be the full bottom
half.
When wearing
bifocal specs, looking up through the lens will allow you to focus and get a
clear vision of things that are far away and looking down through the lens will
allow you to focus and get a clear vision of things that are nearby.
Research has
shown that by wearing Bifocals, progressive myopia in children can well be
controlled. If the accommodative response (time lag before eyes can focus from
one point to another) for children is subject to myopia, then bifocals can
reduce the progression.
Now you will
not have to switch between different specs while reading and watching T.V!
2. Trifocal Lens
These are special
type of multifocal lens because trifocals are a 3-in-1 as they have three lens powers,
correcting for distance, intermediate and near visions and, has by name, three
segments.
Sometimes it
is difficult for eyes to focus on objects that are at arm’s length,
approximately 18 to 24 inches from eyes such as computer and car’s speedometer.
In this case, trifocals work perfect because it has intermediate vision
(eyesight at approximate arm’s length) segment.
Now viewing
objects at any distance has become easy and faster with such technical
improvements. You can have a comfortable vision for objects that are far, near
and within arm’s length
3. Progressive Lens
Progressive lens is a true form of multifocal lens, and they are also
known as “No-Line” lens because as compared to bifocals or trifocals, this lens
have many powers and they have no visible lines as well.
Furthermore, progressive lenses are free from the “image jump” problem
which is why they dominate the multifocal lenses market.
Look around with a comfortable vision without having the problem of
looking up for distant objects, looking down for near objects. The whole lens
is used for every kind of focus level, you can look at T.V, read newspaper and
work on computers all at once.
These are the major form of lens that are used in the industry for
different people with different eye problems. Now you can be sure of which type
of lens you require to get your world clear!