BOX AND DATUM SYSTEM OF SPECTACLE FRAME MEASUREMENT

A system used to quantify the concentration of a slurry based on the specific gravity of the slurry. The previously used datum system for measuring lenses was established as a system of reference points for frames lenses so that placement of lens optical centers bifocal segment heights would be consistent.

How To Measure Glasses Eye Size Lens Width Is The Horizontal By Sizely Medium

This is usually synonymous with bridge size although it is important to note that manufacturers not adhering to the boxing system may mark a bridge size that does not correspond to the distance between.

. For spectacle frames having a significant face form angle the boxed centre distance shall be measured between the boxed centres 21 marked on the back surfaces of lenses of appropriate base curve fitted to the frame. Usually a 2 digit number in. The sum of the two measurements above and below scale A along B is the mid-datum depth.

The Numbers on your Glasses. These numbers usually include the frame model colour code and measurements as illustrated. Width of the lens along the central datum line.

The top example is for a frame with a lens 50 mm wide a bridge size of 17 mm and a temple length of 145 mm. Datum line is a line that is drawn halfway between the two horizontal lines and parallel to the two horizontal line. Shop the Best Fit for Your Face Shape.

From left to right these eyeglass measurements. This letter will also show up in any feature control frame that uses this datum feature as a reference. Thats the A dimension.

In the datum system this was called the datum line. Measurement where an imaginary line is drawn through the middle of the eyewire both in the horizontal and vertical plane. Next measure the DBL or bridge size.

Some may also refer to this section as the arm of your glasses. When measuring an eye size using the datum system an imaginary line is drawn through the middle of the eyewe both in the horizontal and vertical planes. The DBL is the distance between the two boxes when both lenses are boxed off in the frame.

Bevel The angled edge of the spectacle lens. THE BOXING SYSTEM 7. All the Latest Styles.

The boxing system also makes it possible to define the distance between lenses DBL. Box System of Measurement. Ad Browse Our Collection of Eyeglass Frames.

However in the boxing system this line is more com monly referred to as the. The current system is called the boxing system. THE BOXING SYSTEM Geometric Center The center of the lens is the point on the horizontal midline halfway between the two lens-bordering vertical lines.

SPECTACLE FRAME MEASUREMENT Conclusion Based on your own understanding explain about box system and datum system of spectacle frame measurement. Frames may be measured using either one of two systems the Datum System or the Box system. These three numbers are the frames measurements.

The datum features on a drawing are denoted with a series of capital letters. This name continues to be used. Bell gauge See Gauge bell.

First search for the three little numbers on the inside of the temple of your glasses. The datum system preceded the currently used boxing 6. The box system designates the lens width at its widest point the A measurement the depth of the lens at its deepest point the B measurement The halfway point of the B measurement is called the datum line.

Be 145 - 145SG where SG specific gravity. All four lines form a box around the lens Horizontal Midline There is a horizontal line halfway between the top and bottom of rhe lens. Horizontal measurement of box enclosing lens area.

The boxing system is measured by drawing an imaginary box around the lenses and then measuring the lens and bridge between the vertical sides of the box. Horizontal lines were drawn at the highest lowest edges of the lens. The length of those lines correspond to the horizontal and vertical measurements of the eyewire.

The point on the datum line that is halfway between the edges of the lens. If youre a glasses wearer you may notice some numbers on the arms or the bridge. Lastly turn the ruler and measure the B or vertical size of the lens.

To cut lenses so they fit into frames you need to have some sort of system of measurement. SYSTEM IN FRAME MEASUREMENTS. The width of the lens along the datum line is called the datum length or eye.

2 horizontal lines at the highest and lowest edges of the lens. Distance between opposite parallel sides of the box determine the length of the distance being measured. In 1962 the Optical Manufacturers Association adopted the boxing system to provide a standard for frame and lens measurement that greatly improved upon the accuracy of previous systems.

Vertical measurement of box enclosing lens area. Measurements tend to be inconsistent box system imaginary box is drawn around the area to be measured. The numbers 55 18 - 145 in millimetres displayed in this image indicate the following-55 mm will represent the width of the lens.

Thousands of Frames Starting at 6. Hold the ruler over the frame front and sight an imaginary line from the farthest edge of a box touching the left temporal lens edge of the right eye to the right edge of the box. The boxing system creates a box around the lenses so that their shapes and curves are less important.

The depth of the lens measure vertically through the datum center. The current standards render BS 3199197221004 obsolete. Summary of Frame Measurements Box System A.

These letters are in boxes and tied to the datum feature with a black triangle. The Datum system measures the lens and bridge sizes at the 180 line or along a horizontal line midway between the top and bottom of a lens. A feature control frame can reference multiple datums at once and each one can be.

See Distance boxing center. The depth of the lens measured as the vertical depth through the datum center was the mid- datum depth. The older system was called the datum system but it was capable of producing some confusing measurements.

Note 1 to entry. These vertical lines are placed against right and left edges Of the lens. DATUM SYSTEM BOXING SYSTEM 2 3.

Datum Line and BoxingSystems Critically Compared. Be An abbreviation for degrees Baume. BCD Boxing center distance.

21004 defines the datum length and mid-datum depth of the lenses. A New Day A Fresh Look. Width of the lens along the datum line-- eye size.

The boxing system is based upon the idea of drawing an imaginary box around a lens shape with the boxs sides tangent to the outer most edges of the shape. The sum of the two measurements on each side horizontally of the datum centre is the horizontal datum length always recorded first.

Frame Measurementsand Markings