Flawless or error-free glasses are vital to the individual as they are a sign of his/her style, the main function of the eyeglass frame is to place the precisely defined lenses in front of your eyes, and therefore choosing the correct size of the frame is an important stage in the vision correction process.
What do those numbers inside your glasses mean?
These are the main measurements that make up the size of your glasses.
Measurements
Lens height
It is the height of any of the lenses measured vertically in millimeters
Lens width
It is the width of any of the lenses measured horizontally in millimeters
Frame width
It is the total width of the tire from one side to the end, which includes the frame parts or the hinges, if any, and is measured in millimeters
Chassis arm length
It is the length of the arms on either side of the frame that extend from the hinge to above the ears to keep the glasses on the wearer's face
bridge width
It is the width between the two lenses and is measured in millimeters from the inner edge of one lens to the inner edge of the other lens
Self test
Finding the right size for your glasses
There are two main widely accepted methods of finding the correct size of eyeglasses, the credit card method, which is used when no previous eyeglasses are available.
The first method: the credit card method
The first step in this method is to stand in front of a mirror and place the edge of a credit card over the center of your nose as shown in the pictures below, then look at the end point of the second edge of the card.
young
If the card extends beyond the end of the eye, your glasses may be small.
Center
If the card only reached the end of the eye, your glasses are probably a medium size.
big
If the card hardly reaches the edge of the eye, your glasses may be oversized
Method 2: From your current glasses
Do you already wear glasses? If yes, look inside the frame arm on some printed numbers (lens width - bridge size - frame arm length) as shown below:
Note the lens width and match the correct size corresponding to you in the table below:
Size separation
| Size class | glasses (lens view) | sunglasses (lens view) |
|---|---|---|
|
YOUNG 
|
40-48 mm | 40-55 mm |
|
CENTER 
|
49-54 mm | 56-64 mm |
|
BIG 
|
55-58 mm | >64 mm |
|
VERY BIG 
|
>58 mm |
Notes:
* The frame is a medium size that is perfect for most faces.
*Minimum 28-30mm lens height is required for multifocal prescriptions such as bifocal and progressive as well as prescription sunglasses
