Practice Quiz

ABO NOCE Basic Opticianry

Category - Ophthalmic Products

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What does the 55□18 mean when seen on a frame?
  1. The frame is 55 mm wide measuring both lenses together and 18 mm in height
  2. Each lens in the frame is 55 mm wide and the bridge is 18 mm wide
  3. None of the above
Explanation
Answer: B - The markings of 55□18, indicates that each lens in the frame is 55 mm wide and the bridge is 18mm wide.

This is the measurement from inside the eyewire and does not include the eyewire edge.

This is a crucial measurement that the lab must in addition to the pupillary distance measurement in order to be able to determine where to place the prescription in the frame.
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