LENS TYPES
Single Vision: This all-purpose lens is available in
all materials and can be used for either distance or
near vision correction.
Multifocals: Suggested when both a distance and
near correction are needed together in a single
lens.
No-line progressives: Corrects for far (driving a
vehicle), intermediate (viewing the dashboard) and
near (reading a map.) Because there is no visible
line, progressive lenses have the appearance of
single-vision lenses and are therefore the most
cosmetically desirable multifocal. Progressives are
available in all lens materials.
Lined Bifocals: Provide both far (driving )and near
(reading a map) correction in one lens.
Lined Trifocals: Lenses with visible lines. The
majority of the lens is for distance viewing, while the
center portion is divided into intermediate and near
viewing segments.
Hi Index: (aka Aspheric): Recommended when a
prescription is either “high-minus”, meaning lenses
are thicker at the outer edges, or “high-plus,” when
lenses are thicker in the middle. Flatter lenses
enhance lens appearance by reducing edge or
center thickness. They are lighter weight and can
provide edge-to-edge visual clarity by utilizing an
aspheric or atoric design.
Specialty lenses: Recommended for certain work,
hobby or other recreational uses that require taskspecific viewing for the best visual protection and/or
performance.
Computer lenses: If you’re viewing a computer
video display terminal (VDT) for more than two
hours a day, you may need variable focus lenses.
These lenses help correct vision for the distance
between your eye and the computer screen. A
variety of computer-specific lenses include special
filters, tints, and anti-reflective properties.
Tinted lenses: The majority of lenses can be tinted
from light to very dark. Tints for sun lenses are
usually medium to dark shades, and can be solid
through the whole lens, or gradient, darker on top
fading to lighter or clear at the bottom of the lens
LENS COATINGS
SUN PROTECTION
Transitions® Lenses: These are photo-chromatic
lenses that darken and lighten according to light
exposure. If the wearer is in the sun, photochromatics darken, if indoors, the lenses are
virtually clear.
Photo-chromatic lenses are
available in most lens materials and lens designs.
Ask your eye care professional for a demonstration.
These are best suited for outdoor use as they don’t
turn dark behind a windshield.
Polarized lenses: The top pick for eliminating
glare. Hunters, boaters, fishermen, golfers, and
drivers are a few who benefit from polarized lens’
glare-cutting properties. Any surface can create
glare in sunlight, including water, sand, snow,
windows, vehicles, and buildings. Polarization
eases eye stress and fatigue in the sun, and comes
in several color and density options.
UV protection: The sun’s ultraviolet rays pose
potential harm to your eyes. UV protection on
lenses accomplishes the same thing as sunscreen
lotion on your skin–– it protects your eyes from
harmful ultraviolet rays. Plastic and glass lenses
may require UV coating, while high-index and high
impact resistant lenses provide UV protection
inherently in the lens material.
Scratch-resistance coatings: Recommended to
protect lenses from everyday wear-and-tear. Some
materials, such as high-impact resistant, high-index
lenses, and several new plastic lens designs,
include scratch protection
Anti-reflective: Anti-reflective, or “AR” lenses help
reduce eye fatigue in all situations, particularly
while viewing computer screens and driving at
night. In addition to enhancing vision by removing
distracting reflections, AR lenses are cosmetically
desirable, as the wearer’s eyes are clearly visible
behind the lenses.
COMMON VISION DISORDERS
Myopia or Nearsightedness: Affects a significant
number of people, but this eye disorder is easily
corrected with eyeglasses or contact lenses or
surgery. People with myopia or nearsightedness
have difficulty seeing distance objects, but can see
objects that are near. For example, a person who is
nearsighted may not be able to make out highway
signs until they are just a few feet away.
Farsightedness often starts in early childhood, but
normal growth corrects the problem. If a child is still
a bit farsighted when the eye has stopped growing
(at about 9 yrs of age) the eye can usually make up
for the problem. This is called accommodation.
Symptoms include:
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Blurred vision - especially at night;
Trouble seeing objects up close;
Aching eyes, eyestrain and headaches.
Presbyopia: Part of the natural aging process of the
eye and can easily be corrected. Presbyopia is the
loss of the eye’s ability to change its focus to see
objects at near. It is not a disease. It is as natural as
wrinkles and affects everyone at some point in their
life, usually around age 40.
Symptoms include:
Presbyopia is often confused with farsightedness, but
the two are different. Presbyopia occurs when the
natural lens of the eye loses flexibility.
Headaches
Eyestrain, squinting when driving,
Playing sports or looking more than a few feet
away.
Hyperopia or Farsightedness: People who are
farsighted see things at a distance more easily than
they see things up close. Farsightedness occurs
when light entering the eye focuses behind the retina
instead of directly on it. This is caused by an eye
that is too short, whose cornea is not curved enough,
or whose lens sits farther back in the eye than
normal. Also runs in families. Before age 40 the eye
accommodates to eliminate the hyperopia, and after
that, glasses, contacts or surgery may be needed to
correct vision.
Optics
and
Eyewear
People who are nearsighted have what is called a
refractive error. In nearsighted people, the eyeball is
too long, or the cornea has too much curvature, so
the light entering the eye is not focused properly.
Images focus in front of the retina, the light sensitive
part of the eye, rather than directly on the retina,
causing blurred vision. Nearsightedness runs in
families and usually appears in childhood.
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Everything you wanted
to know about . . .
Symptoms include:
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The need to hold reading material at arm’s
length;
Blurred vision at a normal reading distance;
Headaches or fatigue from doing close work.
Bifocals are often prescribed for presbyopia.
Astigmatism: is caused by an eye that is not
completely round. In a person with astigmatism, the
eye is shaped more like a football than a sphere. For
this person, when light enters the eye it is refracted
more in one direction than the other, allowing only
part of the object to be in focus at one time.
Astigmatism is a natural and commonly occurring
cause of blurred or distorted vision. The exact
cause is not known.
G.M. SALLY MELLGREN, M.D. INC.
3621 Vista Way
Oceanside, CA 92056
760-757-1144
www.drsallymellgren.com