When you shop at JoyLot.com you will find plenty to see! JoyLot.com
offers the best prices and selections for all of your eyewear needs.
Choose from eyeglasses, prescription eyeglasses,
sunglasses,
prescription sunglasses and goggles from all the best brands right here
and right now! Choose from Judith
Leiber, Ralph
Lauren, D&G,
Carrera,
Versace,
Dsquared2, Ray
Ban, Bolle,
Revo, and many others all on sale at
discounted prices. As an authorized distributor we guarantee the lowest
discounted sale prices on all models. All of our prescription orders filled are custom made to
the prescription information that you provide. JoyLot.com recommends you
retesting your eyes if your prescription is 1 year old or more. This
will ensure that you are getting an up to date prescription enabling you
to see your best.
Types of Prescription Lenses
There are 4 prescription lens types. You will have
either single vision, bifocal, trifocal and progressive
lenses used to complete your Rx order. Your eye exam will yield a
prescription that will determine which is right for you:
Single vision lenses - These types of lenses have
just one viewing area throughout the lens. The corrected area for
vision is set for either far distance, near distance or for
reading.
Bifocal lenses - These lenses take care of 2 distinct
viewing areas; the first area is for distance and the second is for the
near area. The distance area is designed similar to the single vision
lens meanwhile the near area consists of the prescription for the
distance and the ADD power for viewing at a reading distance. The
ADD power is the part of the prescription that tells the laboratory how
to make the reading field of your multi focal lens, and this can not be
done without an ADD power value.
Trifocal lenses - These lenses are similar to Bifocal
lenses as far as the distance and the near area is concerned, but a
third line of vision, the intermediate area, is added which is the
middle just above the reading area. This viewing area is uncorrected and
gives about an arm's length worth of vision.
Progressive lenses - Progressive lenses are used for
correcting vision on 2 or 3 areas, without the visual line marks viewed
on bifocals and trifocals. Instead of a line there is a
seamless progression from one prescription to the next in each viewing
area.
Prescription Abbreviations and Terms
In this section you will find some of the most common
abbreviations and terms used for prescriptions with
their meanings:
SPH or SPHERE - The
numerical value under ' SPHERE ' is considered the main part
of your prescription. This number measures the strength of the lens
in diopters. Diopters is a unit of measurement that
simply is the inverse of the focal distance of the lens. Simply
put SPHERE is the amount of long or short sightedness and the
numerical value is always accompanied with a plus (+) or minus (-)
symbol above or in front of it. The plus (+) is used for reading
distance and near vision power while the minus (-) is used for
distance power.
CYL
or Cylinder - This refers to the
degree of astigmatism, an uneven roundness present in the cornea's shape which is very
common. You
will see this value empty if you do not have astigmatism.
Axis - When you have astigmatism , a
disturbance in your cornea's shape which is very common , you
will need a special cylindrical lens to correct it which must be
rotated into a specific position along with the lens strength. The
axis represents the rotation amount in degrees ranging from 1 to
180.
Prism - This is used when eyes need to
be realigned when looking at the same item. This can happen
occasionally, in which case prism is ground into the lenses in order
to realign them. When you turn your eye ( known as 'strabismus' ),
or when your eye is under tremendous strain but properly aligned you
will have this occur.
Base - This refers to the rotation of
the prism is specified as ' base in ' or ' base out ' ( ' in ' means
towards the nose ) or ' base up ' or ' base down. ' Vertical and
horizontal combinations of prisms in the same lens can be used in
conjunction with the various base positions.
PD or Pupillary Distance
- PD or Pupillary Distance, is the distance in between the center of
one pupil to the center of the other pupil. The PD is measured in
millimeters (mm) and can also be written in this form: 35/34 (
Normally done if one eye is a little further away than the other
from the center of the nose ).
Step 1. Place the ruler at the bridge of your nose (Click
here to print a millimeter ruler).
Step 2. Ask your friend to stand an arms length away.
Step 3. Please have your friend measure the distance between the
center of
your pupils.
( Please be advised that you will still need to contact your optician to
get accurate Near and Dist PD measurements required only for
bifocal and progressive Rx lenses )
ADD or ADD power - The
ADD power is the part of the prescription that tells the laboratory how
to make the reading field of your multi focal lens, and this can not be
done without an ADD power value. SEG HT or Segment
Height - This is the vertical distance from the bottom of
the lens to the bottom of the wearer's lower eyelid if they are
wearing bifocals, or the distance to the wearer's pupil for progressives
and trifocals. O.D. or OD - is an abbreviation for oculus
dexter, which is Latin for "right eye." (most eyeglass
prescriptions simply say "left" and "right"
instead of "O.S." and "O.D.") Oculus means
"eye." An eye doctor is sometimes called an
"oculist" (although eye doctors themselves usually prefer
to use either the term ophthalmogist or optometrist, O.D. can also
stand for Doctor of Optometry).
O.S. or OS - An abbreviation for oculus sinister,
Latin for "left eye."
O.U. or OU - An abbreviation for oculus uterque,
Latin for "each eye."
D.V. or DV - An abbreviation for "distance
vision". This is specific to the part of the prescription
designed primarily to improve far vision. In a bifocal
lens,
this will normally indicate what is to be placed in the top segment
of the lens.
N.V. or NV - An abbreviation for "near
vision". This will usually represent a single vision
lens prescription to improve near work, or the reading portion of a bifocal
lens.
PL or plo - An abbreviation for Plano
which is used when
no correction is needed. The spherical power will sometimes be
written as "0.00" and sometimes as "Plano" or
"Pl" (because the lens, although not flat, is optically
equivalent to a flat piece of glass).
D.S. or DS - An abbreviation for diopters sphere (it means that you have
sphere power only)
X - This refers to the axis and the number that follows
completes the axis value. As an example x 90 stands for
axis 090.
Some Important Reminders
Concerning Your Prescription
Sample prescriptions
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Please be advised your prescription may be written out on a
blank Rx pad, it does not have to come on a pre-made Rx sheet (
see the sample prescriptions above). The top values are the prescription for the right eye and the
bottom values are the prescription for the left eye.
When there are no numbers for CYL,
AXIS or ADD
in your prescription, leave these fields blank when ordering. If
only one number appears for each eye, it is for the sphere
power only.
On some prescriptions there will be no
astigmatism correction for one or both eyes. Your doctor may
just write the sphere power alone, or may use abbreviations like SPH
("sphere") or D.S. ("diopters sphere").
When you see only one ADD power on your
prescription for bifocals, this means that the same
ADD power is
used for both eyes. Please note if there is no ADD power given, leave this
section blank when ordering.
Please note that you may not be able to
see well with your new prescription sunglasses if you enter
incorrect prescription information such as inaccurate pupillary
distance measurement when placing your order! Please note that
we cannot be responsible for mistakes in prescription information
provided by you or your optometrist or ophthalmologist.
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