How to accurately measure lenses

The current method used to measure lenses is called...

• Boxing method

• Datum method

The method that is NO LONGER used to measure lenses is called...

• Boxing method

• Datum method

"ED" stands for...

• Eat Daily

• Everything Does

• Effective Diameter

• Even Diameter

"DBL" stands for...

• Down Below Lenses

• Distance Between Lenses

• Definitely Be Loud

• Distributed Business Logic

Measurement "A" stands for...

• How round the glasses are

• The length of the arms

• The width of the lens (horizontal)

• The length of the lens (vertical)

Measurement "B" stands for...

• The length of the lens (vertical)

• The DBL

• The width of the lens (horizontal)

• How long the ruler is

Why do we need to measure the lens size?

• To determine the size of the lens

• So the Lab knows which 'blank size' to choose

• So we know if a prescription can be used in this frame

• ALL OF THE ABOVE

What unit of measure do we use when measuring lenses?

• Kilogram
• Dioptre

• Millimetre

• Meter

When ordering glasses,
rather than measure the lenses, we can just 'guess' the size of a lens.

• True

• False

The rule for measuring ED (Effective Diameter) is...

• Measure from the widest edge of the lens to the geometric centre.
  Times this number by 2.

• The ED is not a measurement used

• Measure from the corner of one lens to the other

• Measure around all sides of the lens and add them together