Your prescription is important as it will tell if you’re Shortsighted (can’t see far) , Long Sighted ( could see distance and near but might experience : Frontal Headaches, Burning and Watering eyes ), or if you have Astigmatism (blurry vision plus eyestrain) or Presbyopia (An age related inability to read fine print that starts at or around the age of 40 years old).
We will discuss what the numbers/abbreviations on the prescription mean today, and dive deeper into the other elements later in the next few segments. It’s important to note that a prescription for eyeglasses is written in a standardized format, this is done so it can be interpreted worldwide.
Let’s start with the abbreviations, You may see “DV” and “NV” indicated on your prescription form, this indicates whether vision correction is needed for distance vision (DV) or near vision (NV). You may also see the abbreviations O.D and O.S; these are simply terms for the right eye or left eye. For example, the right eye is the Oculus Dexter (O.D) and the left eye is the Oculus Sinister (O.S). If you see an abbreviation of DS (Dioptre Sphere), this means that Astigmatism is not present.
Now that you’re familiar with the abbreviations, let’s move on to the numbers on your prescription.
The 1st number on your prescription indicates the spherical lens power/ strength needed to correct your short-sightedness or long-sightedness.
If the number starts with a minus sign (-), the lens power would be one to correct short-sightedness. If the number starts with a plus sign (+), then the lens power would be one to correct long-sightedness.
The 2nd number is called the “cylinder” power, and it’s prescribed for the correction of Astigmatism. If there is no second number then the eye is totally Spherical and as mentioned above, you will see the symbol DS.
The third number, the “axis” indicates the location of the lens correction (cylinder) for persons with Astigmatism. The value for the axis ranges from 0-180 degrees. If you don’t have Astigmatism, this part of your eyeglasses prescription will be left blank.
The 4th number is known as the “prism” which is used to correct uneven or misaligned eyes, commonly called Squints. You may also see the words “PD” (Pupillary Distance) written, with a notation. The PD is simply the distance between the center of your pupils.
If the cylinder (CYL) field is blank, then you don’t have Astigmatism, or you only have a very mild form that doesn’t need correcting. A minus sign (-) corresponds to short-sightedness and a plus sign (+) corresponds to long-sightedness.
Another aspect of your prescription related to Astigmatism is the “axis”. The “axis” is a number ranging from 0-180 degrees. If you don’t have Astigmatism, this part of your eyeglasses prescription will be left blank.
If your prescription indicates that you need a cylindrical lens power (for Astigmatism), then you’ll also have an axis power. The axis number tells the eyeglass manufacturer where on your lens the astigmatism correction should be located. also see the words “PD” (Pupillary Distance) written, with a notation. The PD is simply the distance between the center of your pupils.
If you have Presbyopia and need multi-focal lenses (Bi-focal/ Progressives), you will see numbers in both the Distance vision (D.V) and near vision (N.V) sections of your prescription.
In addition to the above, you may also see the word “Add” written below “Distance” on your prescription. “Add” is a number that will represent the magnifying power to be added to the lower half of your progressive or bifocal lenses, this is done to help restore your near vision. The “add” number is typically the same for both eyes.
Once your near vision s restored, you won’t have to worry about holding your reading material at arm’s length in order to see it!