A lens prescription shows the parameters needed to correct your vision. This document is also known as a glasses prescription and will be made by an ophthalmologist or optician-optometrist.
In this article, we explain what each of the values included in the prescription mean.
OD: Right eye.
OI or OS: Left eye.
SPHERICAL, SPHERICAL POWER or SPHERE: This is the myopia (nearsightedness) or hyperopia (farsightedness) value.
CYLINDER: This value shows how much astigmatism you have and can appear with a positive or negative sign. Example: -1.50 or +1.25
AXIS: This value is measured in degrees and shows the position of the astigmatism, between 0º and 180º. Example: 50º
CENTRES, PD or IPD: This value indicates your inter-pupillary distance and is expressed in millimetres. It measures the distance between your pupils. It can be written in two ways in your prescription: total value (Example: total DP 63) or for each eye (Example: OD 32, OI 31).
NEAR ADDITION, ADD or ADDITION: NEAR ADDITION refers to the total value of the nearsighted prescription. If you see just the ADD acronym or ADDITION, it won't show the nearsighted prescription. This number must be added to the spherical power.
The addition value is usually the same in both eyes. In most cases, you'll see it only once per prescription, with no differentiation between one eye and the other.
Examples for calculating near graduation with ADD or ADDITION value.
Example 1:
-2.25 (Spherical Power) + 1.25 (Addition) = -1.00 (This number will be your sphere value for nearsightedness). It's an algebraic sum and, as they're different signs, they're subtracted from one another.
Example 2:
+2.50 (Spherical Power) + 1.25 (Addition) = 3.75 (This number will be your sphere value for nearsightedness). It's an algebraic sum and, as they are equal signs, they're added together.
Buying single-vision lens glasses
When buying single-vision lens glasses on our website, you'll need to include the spherical power value in our prescription assistant. If you have astigmatism, you'll need to include your cylinder power and axis values too.
Example single-vision prescription glasses order on our website
Prescription:
OD: SPHERE -1.25 CYL -1.00 AXIS 85º
OI: SPHERE -2.25
IPD or PD 63 mm
Example by adding the graduation in our online wizard
If you're under 40, these glasses will help you see well at all distances.
If you're over 40, the prescription will be set according to the distance you want to see well at. A specialist will help you determine the correct prescription according to your needs.
A prescription can correct distance, intermediate or near vision (40 cm).
In some exceptional cases, such as with cataract surgery or with people under the age of 40 who have other eye health conditions, a prescription will be determined by the specialist according to the type of impairment.
Buying progressive lens glasses
If you want to buy progressive lens glasses on our website, you only need to include your distance prescription and addition value on the prescription assistant.
We show you a real example so you can see how to do it.
Prescription:
OD: SPHERE -1.25 CYL -1.00 AXIS 85º
OI: SPHERE -2.25
ADD: 2.25
IPD or PD 63 mm (in this case, 31.5 mm per eye)
Example single-vision lens prescription glasses order on our website
If you have any questions you can contact us through our e-mail [email protected]. We will help you in everything you need.