In order to make bifocal, trifocal or progressive lenses, segment height is required as it will determine exactly where the reading portion has to be fitted. Often known as Seg Height or SH, segment height is the vertical measurement from the bottom of the lens to the pupil. This formula helps to get accurate glasses, most of the time. The measurement is specific for each frame and the person wearing it.
Segment height is however not necessary for single vision lenses. Usually, doctors do not mention segment height measurement but you can comfortably measure it at home by yourself or taking any friend's help.
How to measure segment height at home?
It is possible to measure segment height on your own at home. You just need:
Once you're ready follow the steps below:
- First of all, you have to put on any glasses to get the measurement
- Now face the mirror and stand 8 inches away from it (make sure the space is well lit)
- Align the ruler in a vertical position with 0 mm measurement on the bottom of the lens (Remember - 0 mm mark should be placed on the bottom of lens and not frame)
- Look straight ahead and check the millimetre line that ends at the centre of pupil, it is your segment height measurement (from bottom of the lens to centre of pupil)
- Repeat the above steps 3 to 5 times constantly, so that you get an accurate measurement
If you find it difficult to do it yourself, you can ask your friend or family member to take the reading.
So with this segment height, you can now order perfect pair of glasses at Framesbuy and experience enhanced vision.