Have you ever wondered what the numbers on your prescription
lenses mean? We at Daniel Walters want to make you more knowledgeable about eyeglasses
by helping you read the numbers in your prescription sheet. In this
article, we are going to interpret what all these abbreviated letters and figures mean for you to
get a full understanding of your vision status.
If you try to look at your prescription, you will see
the letters OD an OS quite a lot. What do these codes stand for, you ask? OD and OS are acronyms for the Latin words oculus dexter and oculus
sinister. Oculus dexter refers to the right eye while oculus sinister refers to
the left eye. Some clinics have decided to replace OD and OS with RE and LE
which seems more straightforward.
you will see the code OU which stands for oculus uterque, meaning both eyes.
SPH is short for the word Sphere. Measured
in Diopters (D), the number under SPH shows
the amount of lens power prescribed by the eye doctor to correct nearsightedness
or farsightedness. Nearsightedness or myopia is when you are more adept to
seeing things in a shorter distance while farsightedness or hyperopia is the
opposite. A negative sign (-) on your SPH means that you are nearsighted while
a positive sign (+) or the absence of the minus sign means that you are
farsighted. The severity of your eye problem goes higher as the numbers on your
SPH moves away from zero (0).
CYL is short for the word Cylinder. Your CYL basically
shows how much power your lenses need to correct astigmatism. Astigmatism is
when your eye finds it difficult to focus the light it receives to interpret
objects sharply. The number could have a negative sign on it to adjust an eye
with nearsighted astigmatism or a positive sign for an eye with farsighted
astigmatism. Cylinder power is
always in accordance to the sphere power.
A blank space on the CYL
section basically means that your eyes are free of astigmatism or they are way
too mild to be treated.
Axis identifies the lens meridian that holds no cylinder power to fix
astigmatism. It is measured with numbers from 1 to 180. The number 90 parallels
to the vertical meridian of your eye, and the number 180 aligns the horizontal
meridian. Accurate lens prescriptions with an indicated cylinder power will
always have an accompanying axis value which proceeds after the CYL number and
is preceded by the letter “x”.
Add stands for
the added magnifying power
applied to the lowermost part of multifocal lenses. This is made for lenses prescribed to elder people
with presbyopia or farsightedness caused by the natural process of aging. The number for added magnifying power is always going to
be positive and it could be stated with or without a plus sign. The number
commonly moves in a scale of +0.75 D to +3.00 D for both eyes.
Charles Stone of New York CSNY 503
Prism indicates a number showing the prismatic power
to correct eye alignment problems. Not a lot of prescriptions have this but
just to let you know, prism is measured in prism diopters or p.d. Prism
diopters can also be written in the form of a superscript triangle.
PD stands for Pupillary
Distance or the distance between the centers of each pupil. This number will
never have to change once you reach the adult age. The pupillary distance
number plays a significant role in ensuring accurate lens fitting. The
measurement of the proper PD allows the center of the lens to align with the midpoint
of the pupil for your visual comfort and function.
Daniel Walters offers
everyone stylish eyeglasses with accurate prescription in very affordable prices.
Choose from a wide variety of eyeglasses starting from those above and send in
your prescription today!