Frame measurements and markings serve practical and sometimes aesthetic purposes, helping users identify, install, or appreciate the frame properly. Measurements: Frame measurements usually include dimensions such as width, height, and depth. These measurements are essential for ensuring that the frame fits the intended object or space. Markings: Markings on a frame can vary depending on the type and purpose of the frame.

1. FRAME MEASUREMENTS AND MARKINGS
PRESENTED BY MIFTAHUL ISLAM
OPTOMETRY INTERN
(2023-2024)

2. DATUM SYSTEM
• The line drawn halfway between the two line horizontal and parallel to them was
known as the datum line .
• the width of the lens along this line was called the datum length or eye size .
• the point along the datum line halfway between the edges of the lens is the datum
center .
• the depth of the lens measured as the vertical depth through the datum center, was
the mid datum depth .
• the datum system preceded
the currently use boxing .

3. BOXINGSYSTEM
What is boxing system :- This system intriduce in 1962 to provide a standard for
frame and lens measurement . this system was ans improved version of datum
system.
It is an idea of drawing an imaginary box around a lens shape with box side
tangent to the outer most edge of the lens shape.
The system uses the sides of the boxes as reference points for the standers
system of measurements.

4. A MEASUREMNT:-
It is measured as the
horizontal distance between
the furthest temporal and
nasal edge of the lens shape
or the distance between
the vertical side of the box.
the measurement is also
known as the eye size.

5. B MEASUREMENT
• It is measured as the vertical
distance between the furthest top
and bottom edges of the lens
shape or the distance between the
horizontal sides of the box. This
is measured in millimetres.

6. GEOMETRIC CENTER (GC)
The centre of the lens is the point on the horizontal midline halfway
between the two lens bordering vertical line . it is known as
geometrical centre or boxing centre of the edged lens
FRAME DIFFERENCE
The difference between the horizontal and the vertical
measurements is known as frame difference and is measured in
millimetres . the larger difference , more rectangular the enclosing
box appears .

8. DISTANCE BETWEEN LENSES(DBL)
• The DBL is the distance between the two boxes when both lenses
are boxed off in the frame . it is also referred to as bridge

9. TEMPLELENGHT
• Most temples currently marked with the total, or overall temple
length , temple length are expressed in millimetres .
OVERALL TEMPLELENGHT
The overall temple length is the distance from the centre of the barrel screw
hole to the posterior end the temple measured along the centre of the temple .

10. LENGTH TO BEND (LTB)
• this is measured from the centre of the barrel to the middle of the
bend (LTB) . the distance from the middle of temple bend to the
end of the temple is known as length to drop .

11. FRONT TO BEND (FTB)
• If the end pieces wrap around in a swept back menner there is a
distance between the plane of the temple length could be specified
as front to bend (FTB)

12. FRAME MARKING
• The most frame marked according to size with three measurement
eye size , DBL and temple length .
• Metal frames that are manufactured from rolled gold are also
marked as to the amount of gold found in the frame .

13. EYE SIZE AND DBL
• When a frame marking such a frame as 50 20 is seen , it means
that the eye size is 50 mm and the distance between lenses is 20
mm .
• The box – the eye size is measured according the boxing method .
• The eye size and dbl are sometimes simply marked 50-20 or
50/20 .

14. LOCATION OF MARKINGS
PLASTIC FLAME :-
printed on the inside of the nose pad, or on the upper outer section of the
eye wire .
back side of the end pieces, and the temple must be folded closes to find it
.
on one end pieces and the DBL on the other
METAL FRAMES :-
eye size and DBL are usually on the inside of the bridge or on the temples
.