What it means and why
Fitting height locates a design’s fitting reference vertically in the selected frame. The exact reference and measuring method depend on the lens design and laboratory instructions. It is not simply the full height of the lens opening.
The frame should first sit in its intended position. Tilt, nose-pad adjustment and slipping can change the relationship between pupils and lens zones; a height copied from a differently fitting frame may no longer place those zones correctly.
A worked example
Teaching scenario: a progressive is measured while the frame sits high, but the loose frame slips after collection. The recorded number has not changed, yet the lens zones have moved relative to the eye. Assess frame stability and the original fitting before deciding to alter the prescription.
What it does not tell you
Do not choose a universal fitting height from a face photo. Two eyes can require separate values, and a design’s minimum fitting requirement is not the same thing as the wearer’s measured height.
THINK IT THROUGHShould a slipping frame be adjusted before measuring height?
After establishing the intended fit, using the selected design’s measuring procedure.
Sources & reading notes
Page updated:
- ZEISS · Which frame for what lens? (manufacturer guidance) ↗ Manufacturer information
Documents the maker’s specifications or positioning for a market; it does not establish independent superiority or personal suitability.