Segment height is a measurement needed when ordering progressive or bifocal glasses online. It refers to the vertical distance from the bottom of the lenses to the pupil. Knowing the segment height ensures the reading portion of progressive lenses is placed correctly. If the current frames are unavailable, measure similar frames owned to get the height and width for fitting purposes. The document then provides steps to accurately measure segment height with a ruler by aligning it with the bottom of the lens while facing a mirror.

1. O P T O M . A S K A R P K
Segment Height Measurement

2. What is it? And why is it
relavant when ordering
progressive or bifocal
glasses?

3.  Segment Height, can also be known as Seg Height or
SH and it is a value that may or maynot be included
in your progressive or bifocal prescription

4.  When you order progressive or bifocal glasses
online the segment height is a very helpful
measurement and while not all doctors will provide
this measurement even when ordering glasses in
person this measurement is very specific to the
actual frame and the person wearing them

5.  This is the distance (the vertical measurement) from
the bottom of the lenses to where your eyes (pupils)
are.
 You need this measurement so that when you order
your progressives the optican will know where to put
the reading portion of your glasses
 Segment height does not apply to Single Vision
lenses
 What can you do if you don't have the glasses you are
about to order on hand?

6.  Measure the glasses that you currently own and try
to find glasses very similar to those
 The measurement to look for in this case is the
height and for fitting purposes the width of the frame

8.  How to Measure Your Segment Height
 1. Use a ruler that has millimeter measurements. You
can also use a ruler with centimeter measurements
and simply times the result by 10 to get
your millimeter measurement.
 2. Put the glasses on your face and adjust them so
that they sit comfortably.
 3. Stand about 8 inches (20 cm) away from a well lit
mirror with your face parallel and square to the
mirror.

9.  4. Align the ruler's zero (0) measurement to the lowest
point at the bottom of your lens, keeping it exactly
vertical. Make sure you are measuring from the bottom
of the clear lens, not the bottom of the frame (see graphic
above).
 5. Stare straight ahead and read the millimeter line that
lines with the center of your pupil. This is your segment
height measurement for these frames.
 6. Repeat these steps at least 3 to 5 times to get an
accurate and consistent measurement. Make sure your
head and the ruler do not move after lining up the zero
(0) measurement with the bottom of your lens until you
note your measurement. Ask a friend to help if you are
having trouble.

10. Thank You