What is the B number on glasses?
Vertical Size (B) – refers to the vertical height of an eyeglasses lens, and is measured from the tip to the bottom of the lens aperture of the frame. The measurements are taken from a horizontal line intersecting with the top of the lens, to the horizontal line intersecting with the bottom edge of the lens.
What do the codes on glasses mean?
The numbers beneath the frames reflect the SIZE MEASUREMENTS in millimeters (mm). THE FIRST NUMBER (ex.54) = the width of the lenses. THE SECOND NUMBER (ex.15) = the distance between the lenses. THE THIRD NUMBER (ex.140) = the length of the temple arm including the portion going behind the ear.
How do I identify my eyeglass frames?
Eyeglass frame sizes are indicated by three numbers stamped on the inside of your eyeglasses. These numbers usually appear on the inner surface of one of the frame temples that hold your glasses in place behind your ears.
What do the 3 numbers on eyeglass frames mean?
1) The eye size number (it is the size of the lenses on your frame). 2) The bridge size number (the distance between the lenses). 3) The temple length number (it is the size of that part of your eyeglass frame, which rests upon your ears).
What is b depth?
The second measurement is the “Lens Depth” and is sometimes referred to as the “B” measurement. This is simply the depth of the lens measured in millimetres as per the diagram below.
What does SPH mean for glasses?
Sphere (SPH) – The term “sphere” means that the correction for nearsightedness or farsightedness is spherical, equal in all meridians of the eye. This indicates the amount of lens power, measured in diopters (D), prescribed to correct nearsightedness or farsightedness.
What does 52 mean on glasses?
Answer: They’re size measurements in millimeters. They’re measurements. The first number (e.g. 52), is the width of the lenses. The second number (e.g. 20) is the distance between the lenses. And the third number (e.g. 135) is the complete length of the temple arm, which includes the portion that goes behind your ear.
How do I read my eyeglass prescription?
When you look at your prescription for eyeglasses, you will see numbers listed under the headings of OS and OD. They are Latin abbreviations: OS (oculus sinister) means the left eye and OD (oculus dextrus) means the right eye. Occasionally, you will see a notation for OU, which means something involving both eyes.
What do the numbers in eye prescriptions mean?
A “plus” (+) sign in front of the number means you are farsighted, and a “minus” (-) sign means you are nearsighted. These numbers represent diopters, the unit used to measure the correction, or focusing power, of the lens your eye requires.
How do I know what size glasses to get?
The width of your frames should not be wider than the width of your face at the temples. The top of your frames should be no higher than the line of your eyebrows. The lower edge of the frames shouldn’t sit on your cheeks otherwise they will start to rub against your skin and cause irritation.