Reading Your Prescription
This page describes how to read your eyeglasses prescription, based on the sample prescription below. If after reading this document, you are still having difficulty reading your prescription, please contact our customer support at 1-877-678-4974 or firstname.lastname@example.org. An agent will be happy to assist you.
Sample Eyeglasses Prescription
The prescription for the right eye is on top and the left eye is on the bottom. The right eye prescription is usually marked O.D., but it could also be marked with just an R, or as Right.
The prescription for the left eye is on the bottom. The left eye prescription is typically marked O.S., but it might be marked with just an L, or as Left.
The rest of the entries on your prescription indicate the details of your required vision correction. It is this information that our technicians use to shape your lenses.
- Sphere (SPH)
Measured in diopters sphere indicates how near-sighted or far-sighted you are.
- A plus sign (+) indicates far-sighted vision, or needing glasses to see things near by, like a menu)
- A minus sign (-) indicates near-sighted vision, or needing glasses to see things that are faraway
- Cylinder (CYL)
- Cylinder measures in diopters the degree of astigmatism that you have. Some prescriptions are written in minus (-) and some are written in plus (+).
- The Axis measures the orientation of the astigmatism and it is represented as a number between 0 and 180 degrees.
- Near Add (or Near Addition, or just ADD)
- Bifocal or progressive prescriptions, which correct both nearsightedness and farsightedness, usually have "add" to indicate plus power for near distance or reading. If there is only one ADD power on your prescription for bifocals, this means that the same ADD power is used for both eyes.
- PD (Pupillary Distance)
Your prescription might also come with your pupillary distance.
Pupillary Distance (PD) is the distance (usually measured in millimeters) between the centers of the pupils in each eye. This measurement is used when making prescription eyeglasses. Positioning lenses correctly in relation to the pupil centers is especially important for higher powered lenses. This measurement is usually taken twice: 1st with the patient focusing at a distance, and 2nd at near focus. The 2nd measurement is used for reading glasses, and bifocals. The measurements may also be verified with a pupilometer, since most practitioners take preliminary measurements with a millimeter ruler placed across the bridge of the nose.
- The typical pupillary distance for adults is around 54-68 mm, while measurements generally fall between 48 and 73 mm.
- For children the measurement usually ranges from 41 to 55 mm
Your PD could have one of 3 possible readings
- Total PD is the measurement between your pupils. This measurement is generally good for single vision lenses.
- Left and Right PD is measured if there is asymmetry from the middle of the bridge of your nose to the left and right center of your pupils. We can accommodate prescription accuracy delivering superior function and comfort by custom making your lenses with left and right PD measurements. An example of a left and right PD would be: OD 32/ OS 31.
- Short Point Focus and Long Point Focus PD: Short and Long point focus PD is used for comfort and accuracy usually with progressive and bi-focal lenses. There could be a variance in your PD for seeing distance or close. An example of Short Point Focus and Long Point Focus PD is: 65/61
If your prescription did not include a PD, we recommend you download our PD Ruler, and measure it yourself.