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Aug 2004 |
KODAK Precise™ PolarShades™ Gray and Brown
Progressive Lens in Standard Resin
Product Specifications & Processing Information
Purpose: The following information will assist you in processing the KODAK Precise PolarShades Progressive standard plastic lenses in uncoated and scratch resistant coating.
Summary of Changes: The base curves average values have been updated for the highest accuracy.
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Characteristics |
KODAK Precise PolarShades Lens |
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Refractive Index |
1.499 |
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Dispersion Value (Abbe) |
58.0 |
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Density |
1.32 |
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Polarizing Efficiency |
99% |
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Visible Light Transmittance |
16% |
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UV Blockage |
UVB: 100%, UVA: 99% |
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Chemical Resistance |
Excellent |
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Machinability |
Excellent |
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Rear Surface Coating |
Optional |
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Scratch Resistant |
In-Mold RLXPlus® |
Unique Semi-Visible Mark: K+
Blank Size: 78mm diameter blanks, decentered 3mm.
Effective diameter is 84mm.
Base Curves: 3.25, 5.00, 7.00
Add Powers: 1.00 to 3.00 in 0.25 Diopter Steps
Thicknesses: We recommend a minimum center thickness of 1.8mm
KODAK Precise PolarShades Progressive Standard Plastic Lens Dimensions
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General:
Processes used for surfacing CR-39® lenses should be applied to KODAK Precise PolarShades Lenses.
Computer Calculation of Rx:
The easiest, most efficient method to calculate and process values for an Rx is to use an existing computer software package that contains KODAK Precise PolarShades Progressive Lens design data. If your software does not include this data, our Technical Services group will be happy to provide the necessary specifications. Please forward us the contact name and phone number of your software vendor. If you need a software program for processing lenses, Signet Armorlite has developed a computer program to calculate surfacing data. This program is available through Signet Armorlite's Technical Services Department.
Layout:
All surfacing should be done in relation to the prism reference point located on the 180º axis. The polarizing film axis is on the 180º axis, indicated by the inked line and semi-visible crosses. We recommend that you block the lens on the prism reference point even though the corridor is decentered 3 mm. If blocking is done on the geometric center of the blank, you must calculate the amount of decentration prism needed to move the optical center to the prism reference point. The fitting cross is located 4.0mm directly above the prism reference point dot. If you use an automated lens blocker, such as the Gerber Step-One System, and if you are blocking on the cross, be sure to use a segment placement on the lens blank of -4mm down (4mm up), 3.0mm in.
Lens Thickness:
The polarizing film is designed to be as near to the front surface of the lens as possible. The film location moves away from the lens front surface as the add power of the progressive design increases. Therefore, if desired, it is best to specify a minimum edge thickness depending on the add power. If your system cannot be set for a minimum edge thickness by add power, you may wish to use a minimum edge thickness of 2.0mm. The chart below provides recommendations for lens thicknesses by add power.
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Add powers |
1.00 to 1.50 |
1.75 to 2.25 |
2.50 to 3.00 |
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Min edge thicknesses |
1.6mm |
1.8mm |
2.0mm |
We recommend a minimum center thickness of 1.8mm.
Semi-Visible Marking:
KODAK Precise Lens markings have a “+” at the nasal and temporal sides along the 180º axis line. Approximately 3mm below the nasal “+” you will find the “K+” product code. Approximately 3mm below the temporal “+” you will find the add power of the lens. These marks can be located by visually inspecting the lens. Position the lens at arm's length, preferably in front of an overhead fluorescent light. Slowly move the lens away from the edge of the light fixture while looking at the estimated location of the marks along the surface of the lens. The marks will become visible at a given angle of light.
Removal/Re-marking The Temporary Reference Marks:
The KODAK Precise Lens markings may be removed by wiping the surface with alcohol, acetone, or standard lens mark removing solvents. These marks are designed to withstand all processing procedures. They provide an easy way to verify the edging accuracy and can be removed before or after tinting.
To re-mark the lens, first locate the semi-visible markings, specifically the “+” symbols engraved along the 180º axis line (see above procedure for locating the semi-visible marks). Once you have located the semi-visible markings, dot them on the lens and use the KODAK Precise verification chart for the final re-marking.
AR Coating:
Because lens impact resistance is reduced by AR coatings, we recommend conducting impact tests for lenses AR coated and sold by your lab. It may be necessary to increase the minimum center thickness in order to meet impact resistance requirements. Please call Technical Services at (800) 759-0075 for additional information about coatings and impact resistance.
Fitting and Frame selection:
The fitting point (+) has been positioned slightly higher than our other progressives. Therefore, you can fit the lens at the center of the pupil rather than at the bottom of the pupil. Always use monocular PDs and individual fitting heights when they differ more than 1.0 mm.
We recommend a minimum fitting height (sometimes called the segment height) of 20 mm. While a successful fitting of Precise lenses is possible with less than a 20 mm fitting height, we recommend the KODAK Concise™ short corridor lens for smaller fitting height situations.
The frame shape, frame PD and patient’s PD affect how much of the full addition reading area falls inside the frame. To insure these variables will not limit near vision, lay the frame (with the fit point marked) onto the KODAK Lens Dispensing Aid (part number K763-578.) Check to see if the blue shaded area is contained within each eye of the frame. This chart also references a recommended minimum distance up from the fitting point to the frame edge. We advise a minimum distance viewing area of approximately 12mm for patient comfort.
Kodak is a trademark of Eastman Kodak Company, used under license by Signet Armorlite, Inc.
CR-39 is a registered trademark of PPG.
RLXPlus is a registered trademark, and Precise, Concise, and PolarShades are trademarks of Signet Armorlite, Inc.
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