Segment Height measurement is needed for Bi-focal and Varifocal prescriptions. 

 

We will need the segment height for orders that are for prescriptions with bi-focal or varifocals(progressive). 

Note the difference in measuring difference for Bifocal on the left and Varifocal/Progressive on the right.

 

 

1. Preparation

Before you begin, ensure the frame is properly adjusted to your face. If the frame sits crooked or slides down the nose, the measurement will be incorrect once the lenses are made. Ensure your glasses sit properly on your face. 

• Bridge Fit: Make sure the nose pads or bridge fit comfortably and securely.

• Distance from eye: Ensure the frame isn't sitting too far from or too close to the eyes.

• Ruler 

2. Positioning

• Should be seated or standing comfortably, looking straight ahead with your natural posture.

• The Mirror: Place a small hand mirror on the table in front of you, or use a wall-mounted mirror.

3. The Measurement Process

Note the measurement are different for Bi-Focal and Varifocal. 

The goal is to mark the lens at the specific point where the specialized part of the lens (the "add") should begin.

1. Align Eye Level: Look into the mirror at your own eyes. This ensures your are looking in a "primary position" (straight ahead).

2. Measuring 

   • * For Progressives/Varifocals: Place the ruler vertically and align its 0-mm mark on the centre of the pupil and measure down to the bottom of the lens as shown on the right hand side of the image

   • For Bifocals: Place your ruler vertically and align its 0-mm mark with the lower eyelid and measure down to the bottom of the lens as shown on the left side of the image