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TIPS NO |
239 |
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Revision |
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Date: |
May 2004 |
Kodak Precise™ Progressive InstaShades™ Gray and Brown
1.6 EvoClear® Lens
Product Specifications and Fitting Guide.
Purpose:
The
following information will assist you in processing Kodak Precise Progressive InstaShades 1.6 EvoClear Lenses.
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Characteristics |
KODAK Precise InstaShades 1.6 EvoClear Lens |
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Refractive Index |
1.594 |
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Dispersion Value (Abbe) |
32.0 |
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Density |
1.34 |
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Chemical Resistance |
Excellent |
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Machinability |
Excellent |
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Rear Surface Coating |
Required |
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Scratch Resistant |
In-Mold RLXPlus® |
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UV Blocking |
100% of UV A and UV B |
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Unique Semi-Visible Mark: |
K+6 |
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Blank Size: |
72mm & 76mm diameter blanks decentered 3mm Effective diameters are 78 and 82mm, respectively |
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Base Curves: |
0.50, 1.50, 3.25, 5.00, 7.00, 8.50 |
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Sphere-10.00 to +7.50, Cylinder to -5.00 |
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1.00 to 3.00 in .25 Diopter steps |
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Thicknesses: |
We recommend a minimum center thickness of 1.6mm, or 1.8mm if AR coated, and a minimum edge thickness of 1.4mm. Be sure to add your tolerance to these values for Rx calculation. |
InstaShades
lenses are a MultiMatrix™ product.
The photochromic materials are contained in approximately the front
1.0mm of the lens. The material
behind the first 1.0mm provides the optical properties. The mechanical properties of the lenses
depend on the all of the elements of the MultiMatrix design. Therefore, it is important to surface
the lenses to meet or exceed the recommended minimum center or edge
thicknesses.
KODAK Precise Progressive InstaShades 1.6 EvoClear Lens - Dimensions
General:
These high index lenses have a refractive index of 1.594. Standard pads and polish materials used for surfacing CR-39® lenses are suitable for EvoClear Lenses. If you have questions, please contact Technical Services at 800-759-0075.
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 Lens design data. If your software company has not included this data in its package, 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.
Abrasion Resistance Coatings:
The front surface has the superior protection of the RLXPlus non-tintable coating. Since the uncoated rear surface of the lens will likely not provide adequate durability for normal use, backside coating is recommended. Applying a backside coating after surfacing is required when the lens will be anti-reflective coated. Be sure to verify that impact resistance is maintained, particularly when using a non-tintable coating. Please call Technical Services for the latest test results with various backside coatings.
Layout:
All surfacing should be done
in relation to the prism reference point located on the 180º axis. 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.
Semi-Visible Markings:
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+6” 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.
Special Requirements:
The KODAK Precise InstaShades 1.6 EvoClear Lens processes much like our 1.56 high index and CR-39 lenses.
When cribbing while generating, use a cycle that leaves a smooth edge. Leaving fractured or rough edges can lead to cracked lenses. Lathe style generators may need a slower rough cycle or deeper finish cut to remove subsurface fractures.
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ONE-STEP Fining Pads |
Millimeter Take-off @ 20 sec. intervals |
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Pad Brand & Type |
20 |
40 |
60 |
80 |
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PSI P-1000 |
0.17 |
0.32 |
0.45 |
0.56 |
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DAC
Fire (Fine red vinyl) & |
0.15 |
0.25 |
0.37 |
0.46 |
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0.25 |
0.46 |
0.66 |
0.85 |
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TWO-STEP Fining Pads (DAC) |
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Pad Brand & Type |
20 |
40 |
60 |
80 |
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1st Fine: 600 GRIT |
0.18 |
0.30 |
0.42 |
0.52 |
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2nd Fine: 9 MICRON BLUE |
0.02 |
0.05 |
0.08 |
0.11 |
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1st
Fine: |
0.17 |
0.33 |
0.49 |
0.64 |
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2nd
Fine: |
0.06 |
0.09 |
0.12 |
0.13 |
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POLISHING TIME ( 2 minutes) |
Allow 0.1mm Take-Off |
Fining and Polishing:
Processing the 1.6 EvoClear Lens is similar to the CR-39 lens material. Safety bevel the lens before fining to alleviate chips and allow the slurry smoother access along the lens surface. Large lap tools (at least 3 inch) should be used and allowance made for approximately 0.3mm of stock removal. We strongly recommend fining pads with eight or more petals be used for curves over 9.00 diopters. This can prevent swirls caused by wrinkles in the pads which can result in an aberrated lens. Should you experience unusual reject causes, retain samples and contact Technical Services for assistance.
Edging:
Layout for edging should be done in reference to the fitting cross located 4.0mm above the MRP. The fitting cross is placed at the point of the specified segment height and monocular PD.
Drilling:
InstaShades lenses have been successfully used on three-piece frames that require drilling or slotting. Many variables will contribute to successful three-piece frame usage. They include machining, smooth surfaces, chamfering the edges, using grommets to cushion the contact, not over-tightening the screws, and patient care.
SignetArmorlite recommends
using lens materials with
AR Coating:
Multi-layer AR coatings can be applied to KODAK Precise InstaShades Lenses. Because lens impact resistance is reduced by AR coatings, we recommend a 1.8mm minimum center thickness and a backside coating that will enhance the impact resistance capability. This minimum thickness recommendation is based on surfacing to no less than 1.8 mm and using UltraOptics UVNV backside coating prior to applying AR coating. Other back surface coatings may enhance or reduce the impact resistance.
Be sure that your AR and backside coatings are compatible. If you have lenses AR coated by a coating service, include such samples in your impact testing. 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.
Tinting:
We do not recommend tinting InstaShades lenses. Doing so will void any factory warranty.
Thermal Stability:
KODAK Precise InstaShades 1.6 EvoClear Lens material has a similar level of heat sensitivity as other 1.6 high index materials. The lens will flex if heated under pressure. To prevent warpage, avoid heating the lens over 130°F while under pressure from the frame or clamping during coating. Warpage can cause a plastic lens to become loose in the frame. If the lens should become warped, heat without pressure to allow the lens to return to its original shape.
Call Technical Services for more processing information or technical data. Current customers can find information and TIPS on Signet Armorlite products by visiting our web site at www.signetarmorlite.com.
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.
RLXPlus and EvoClear are registered trademarks, MultiMatrix, InstaShades, Concise, and Precise are trademarks of Signet Armorlite, Inc.
CR-39 is a registered trademark of PPG.
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