Progressive lenses often carry tiny engravings that become visible only under the right light. They are not decorative. After temporary ink markings have worn away, these permanent marks provide a way to re-establish lens orientation and the reference layout. Their symbols and meanings, however, vary by manufacturer and design, so one brand's rule should not be applied universally.
01 · PERMANENT MARK
Permanent markings provide the starting coordinates for reconstructing the lens layout
A progressive lens is a power-variation lens: optical power and prism characteristics change with position. International requirements for this lens category include permanent marking, and products commonly use a pair of small engravings to restore horizontal orientation and reference geometry.
Temporary ink marks showing circles, lines, and a fitting cross can disappear in use; the permanent engravings remain as the reference for later verification and re-marking.
02 · LAYOUT
The engravings are interpreted with the manufacturer's layout chart
Manufacturer charts specify how fitting, distance verification, prism reference, and near verification points relate to the permanent marks. The distances and geometry can differ between designs.
For that reason, a statement such as ‘the fitting point is always a fixed number of millimeters above the engraving’ should not be treated as a universal progressive-lens rule.
03 · INFORMATION
Design, addition, or material information may be encoded, but the system is manufacturer-specific
Some progressive designs engrave identifiers for the design family, ADD value, material, or production information. An optician can compare these symbols with official identification charts to determine the appropriate verification layout.
A single engraving, however, should not be treated as a complete proof of distribution history, every ordered option, or authenticity by itself.
04 · FITTING CROSS
A reconstructed fitting cross helps check wearing position, but it is not necessarily the power verification point
Once the layout is reconstructed, the fitting cross can be compared with the pupil position to review whether the lens was edged and fitted appropriately for the wearer.
The fitting cross serves a wearing-position role, while distance power and prism may have separate defined verification points. Mixing those functions can lead to an incorrect interpretation of measurements.
05 · IDENTIFICATION
Hidden engravings are coordinates for reading the lens, not a stand-alone authenticity detector
Identification should consider the pair of engravings, nearby numbers or symbols, and the manufacturer's official layout together. In small finished frames, some peripheral markings may also be cut away.
When product identity matters, compare the marks with order records, packaging or warranty information, prescription data, and measured lens values.
SOLUTION GUIDE
A practical check order
Use directional light and reflections to locate the paired permanent engravings.
Use the official manufacturer layout to interpret symbols and reference positions.
Restore the fitting cross and verification points according to their specific roles.
When needed, compare order records and measured lens values as well.
GLANOS CHECK
The primary value of a progressive-lens engraving is reconstructing the lens coordinate system after temporary marks are gone.
Permanent marks and the manufacturer's layout should be used together to distinguish fitting position from each optical verification point.
CAUTION
Do not transfer engraving spacing or symbol rules from one manufacturer to every progressive design.
Marking conventions can differ by manufacturer and product. Use the official identification chart or technical guide for the exact lens.
GLANOS EYEWEAR
There is usually a reason behind eyewear discomfort.
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