NV: This term is short for Near Vision. It is used to describe farsighted people who experience difficulty in reading and other tasks that require focus and sharp eyesight, such as cutting or stitching. NV is the amount of power that your reading glasses lens should possess.
DV: The term DV is the opposite of NV, which stands for Distant Vision. Unlike NV, DV does not indicate the power of the lens. Instead, it is an abbreviation that means whether a person is farsighted or shortsighted.
SV: This abbreviation is short for Single Vision. If you have a single vision prescription, you will be able to spot an SV on it. SV tells you you need a single vision lens, not the multifocal lens, bifocals, or progressive lenses.
These were the basic terms that are frequently seen in an eye prescription. Now that you know what they stand for let's get you familiar with the most common parameters in an eyesight prescription.
SPH: Meaning sphere, SPH refers to the power of the lens that is needed to fix your vision.
Prism: Represents people with a specific eye condition that makes them see two images of a single object. Prism indicates the power of the lens required to fix the double vision.
PD: Pupillary distance has two types Monocular PD and Binocular PD. The former represents the distance from the eye pupil to the middle of the nose, and the latter means the distance between the two pupils. Now you know how to measure pupillary distance too.
CYL: The distance between the greatest and weakest eye power is called CYL.
AXIS: This helps determine the direction of how the cylindrical power in the lens should be placed.
ADD: Used in bifocals, it represents the additional power you may require.