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Lens Marking GuidelinesVersion 2.0, June 2014Table of Contents1.FOREWORD32.DEFINITIONS43.RECOMMENDATIONS FOR TEMPORARY LENS MARKINGS54.RECOMMENDATIONS FOR PERMANENT LENS MARKINGS7Page 2

1.Foreword1.1.Scope and PurposeThe purpose of these guidelines is to serve as a reference for placing temporary and permanent markings,such as ink markings and semi-visible engravings, on the surface of a spectacle lens. These guidelines areintended to maximize the accuracy of automatic and manual positioning, processing, and verification inlens production environments. Additionally, these guidelines are intended to provide a consistent set ofrecommendations for placing markings onto progressive and single vision lenses in order to maximizeefficiency for laboratory personnel and eyecare professionals. It is recognized that alternative markinggeometries may accomplish satisfactory results. As such, these guidelines serve as recommendations only.1.2.Normative referencesThe following normative references contain additional terms and guidelines that are applicable to thisdocument. Wherever possible, the terms and guidelines presented in this document have been written inaccordance with these references:Standard for Device Communications, Vision CouncilLens Description Standard, Vision CouncilANSI Z80.1, For Ophthalmic Optics — Prescription Ophthalmic Lenses — Recommendations, AmericanNational Standards InstituteISO 10322-1, Ophthalmic Optics — Semi-finished spectacle lens blanks: Specifications for single-visionand multifocal lens blanks, International Standards OrganizationISO 10322-2, Ophthalmic Optics — Semi-finished spectacle lens blanks: Specifications for progressivepower lens blanks, International Standards OrganizationISO 8980-1, Ophthalmic Optics — Uncut finished spectacle lenses: Specifications for single-vision andmultifocal lenses, International Standards OrganizationISO 8980-2, Ophthalmic Optics — Uncut finished spectacle lenses: Specifications for progressive powerlenses, International Standards OrganizationPage 3

2.Definitions2.1.Glossary of terms and definitionsThroughout this document, the following terms, definitions, and abbreviations shall apply. Whereverpossible, these definitions are consistent with ANSI and ISO definitions.2.1.1.EXCLUSION ZONE (abbr. EZ): An area on the lens surface in which no permanent lens markingsthat could impair the visual function of the lens should appear.2.1.2.FITTING CROSS (abbr. FC): That point on a lens as specified by the manufacturer to be used as areference point for positioning the lens in front of a patient’s eye.2.1.3.FUNCTIONAL MARK AREA (abbr. FMA): An area on the lens surface in which only “functional”temporary lens markings that are utilized for positioning, layout, or power verification should beapplied.2.1.4.LENS(ES)2.1.4.1. PROGRESSIVE: A lens designed to provide correction for more than one viewingdistance in which the power changes continuously rather than discretely.2.1.4.2. SINGLE VISION: A lens designed to provide correction for a single viewing distance.2.1.5.MARKINGS2.1.5.1. TEMPORARY: Removable markings on the lens that are typically non-permanent inkmarkings and removed prior to wear. These markings are often utilized to position thelens during layout blocking and to verify the power and position of the lens duringinspection and dispensing.2.1.5.2. PERMANENT: Irremovable markings on the lens that are typically engraved markingsand either located on an unusable area of the lens blank or only minimally visible toobservers. These markings are often utilized to identify the brand and addition power ofthe lens, if applicable, and to provide reference points for reapplying temporarymarkings.2.1.6.REFERENCE POINT2.1.6.1. DISTANCE (abbr. DRP): That point on a lens as specified by the manufacturer at whichthe distance sphere power, cylinder power, and axis shall be measured.2.1.6.2. LAYOUT (abbr. LRP): That point on a lens as specified by the manufacturer that is usedas a reference point for positioning the lens in front of the wearer’s eye. For progressiveaddition lenses, the LRP is coincident with the fitting cross (FC). For conventionalmultifocals, the LRP is coincident with the location of the segment. For single visionlenses, the LRP is the geometric center (GC) of the lens blank, unless otherwise specified(e.g., decentered single vision aspheric lenses).2.1.6.3. NEAR (abbr. NRP): That point on a multifocal or progressive lens as specified by themanufacturer at which the addition power is measured.2.1.6.4. PRISM (abbr. PRP): That point on a lens as specified by the manufacturer at which theprism value of the finished lens is to be measured. For progressive lenses, the prismreference point is located at the midpoint between the semi-visible alignment referencemarkings (or “engravings”), separated by a distance of 34 mm, along a horizontal axisbisecting those two markings. For non-aspheric single vision and multifocal lenses, theprism reference point and distance reference point are assumed to be coincident.Page 4

Recommendations for Temporary Lens Markings3.1.Progressive LensesTemporary markings for progressive lenses should adhere to the following guidelines when possible(Figure 1):3.1.1.The lines in all temporary markings should be uniform in thickness and 0.1 to 0.4 mm in width.3.1.2.The lines in all temporary markings should be opaque.3.1.3.The design of the temporary markings should satisfy the following criteria:3.1.3.1. Markings should not interfere visually with the permanent alignment markings.3.1.3.2. Markings should be no closer than 2 mm to any permanent markings (engravings).3.1.3.3. If a fitting marking is used, it should be a cross or inverted “T” with a width of no lessthan 4.0 mm. A separate fitting marking should not be used, however, if the location ofthe fitting point coincides with the location of the PRP.3.1.3.4. The PRP marking should be a dot with a diameter of no less than 0.1 mm and no greaterthan 0.4 mm. Clearance around the PRP marking should be maximized.3.1.3.5. The addition power verification area surrounding the NRP should be indicated by acircular marking with a diameter of no less than 8.0 mm.3.1.3.6. The distance power verification area surrounding the DRP should be indicated by acircular mark 10 to 15 mm in diameter, which does not come closer than 3 mm to thefitting cross. This may necessitate a gap in the circle.3.1.4.If present, the 180 axis line should be a solid line, not dotted or dashed. This line shall beinterrupted at, and no closer than 2 mm to, the permanent alignment markings, if present, and nocloser than 4 mm to the PRP marking. This line should extend as far out as practical.3.1.5.The Functional Mark Area (FMA) is defined as a cross-shaped zone centered on the PRP, withlegs 16 mm wide. The FMA should not contain any markings other than those previously defined.In addition, a minimum of 2 mm clearance should be maintained from any of the functionaltemporary markings. The outer 5 mm of the lens is exempt from this requirement.3.1.6.An “R” or “L” marking indicating whether the lens is used for the right eye or left eye is desirable.3.1.7.When applicable, a minimum quantity of ink should be utilized to minimize lens cleaningdifficulty.5.0FMA10.0-15.0 4.00.1-0.4 3.016.03. 2.0 4.0ProductBrandR 2.0 8 .016.0Figure 1 Recommended placement and geometry of temporary markings for progressive lensesPage 5

Single Vision LensesTemporary markings for single vision lenses should adhere to the following guidelines when possible(Figure 2):3.1.1.The lines in all temporary markings should be uniform in thickness and 0.1 to 0.4 mm in width.3.1.2.The lines in all temporary markings should be opaque.3.1.3.The design of the temporary markings should satisfy the following criteria:3.1.3.1. Markings should not interfere visually with the permanent alignment markings.3.1.3.2. Markings should be no closer than 2 mm to any permanent markings (engravings).3.1.3.3. If a fitting marking is used, it should be a cross or inverted “T” with a width of no lessthan 4.0 mm. A separate fitting marking should not be used, however, if the location ofthe fitting point coincides with the location of the PRP.3.1.3.4. The PRP marking should be a dot with a diameter of no less than 0.1 mm and no greaterthan 0.4 mm. Clearance around the PRP marking should be maximized.3.1.4.If present, the 180 axis line should be a solid line, not dotted or dashed. This line shall beinterrupted at, and no closer than 2 mm to, the permanent alignment markings, if present, and nocloser than 4 mm to the PRP marking. This line should extend as far out as practical.3.1.5.The Functional Mark Area (FMA) is defined as a horizontal, rectangular-shaped zone centered onthe PRP, with a height of 16 mm. The FMA should not contain any markings other than thosepreviously defined. In addition, a minimum of 2 mm clearance should be maintained from any ofthe functional temporary markings. The outer 5 mm of the lens is exempt from this requirement.3.1.6.When applicable, a minimum quantity of ink should be utilized to minimize lens cleaningdifficulty. 4.0FMAFMA0.1-0.416.00.1-0.416.03.1. 2.0 4.05.0ProductBrandSeparate Fitting Point and PRP Locations 2.0 4.05.0ProductBrandSingle Fitting Point and PRP LocationFigure 2 Recommended placement and geometry of temporary markings for single vision lensesPage 6

4.Recommendations for Permanent Lens Markings4.1.Progressive LensesPermanent markings for progressive lenses should adhere to the following guidelines when possible inaccordance with the ANSI Z80.1 and ISO 8980-2 standards (Figure 3):4.2.4.1.1.Two alignment reference markings comprising two marks with their centers separated by adistance of 34 mm 0.5 mm, equidistant to a vertical plane through the PRP and locatedvertically at the height of the PRP, should appear on the lens.4.1.2.An indication of the add power of the lens, in diopters, should appear directly below the temporalalignment reference marking.4.1.3.An indication of the manufacturer, supplier, tradename, or trademark should appear on the lens,either as a recognizable alignment reference marking or as a separate marking directly below thenasal alignment reference marking.4.1.4.The Exclusion Zone is defined as a 30 mm, circular zone centered on the PRP. No permanentmarkings that could impair the visual function of the lens should appear within this 30-mmExclusion Zone in accordance with cosmetic inspection guidelines.Single Vision LensesPermanent markings for single vision lenses should adhere to the following guidelines when possible:4.3.4.2.1.If alignment reference markings are present, two alignment reference markings with their centersseparated by distance of 34 mm 0.5 mm, equidistant to a vertical plane through the PRP andlocated vertically at the height of the PRP, should appear on the lens.4.2.2.The Exclusion Zone is defined as a 30 mm circular zone centered on the PRP. No permanentmarkings that could impair the visual function of the lens should appear within this 30-mmExclusion Zone in accordance with cosmetic inspection guidelines.Compensated PrescriptionsIf the fabricated prescription differs from the specified prescription due to a power compensation, it isrecommended that a carat ( ) symbol be placed below the temporal alignment reference marking, ifpresent. For progressive lenses, this symbol should appear to the temporal side of the add power marking.17.0COMP 200ADDARM17.0PRPEXCLUSIONZONELLOGO30.0Figure 3 Recommended placement of permanent markings for progressive lensesPage 7

3. Recommendations for Temporary Lens Markings 3.1. Progressive Lenses Temporary markings for progressive lenses should adhere to the following guidelines when possible (Figure 1): 3.1.1. The lines in all temporary markings should be uniform in thickness and 0.1 to 0.4 mm in width. 3.1.2. The lines in all temporary markings should be opaque. 3.1.3.