TIPS NO

 

248

Revision

 

 

Date:

 

Mar 2006

 

 

 

 

 

KODAK Precise™ InstaShades® PolyClear™ Progressive Lens
in Gray and Brown
Product Specifications and Fitting Guide.

 

Purpose:
The following is provided for fitting and processing KODAK Precise InstaShades PolyClear Lenses.  As with all technical information, please check for updates if a good amount of time has elapsed from the printed publication date.

 

Characteristics

KODAK Precise InstaShades PolyClear Lens

Refractive Index

1.586 ref d

Dispersion Value (Abbe)

28.0 (standard polycarbonate)

Density

1.20

Chemical Resistance

Fair (avoid all solvents except IPA)

Machinability

Good

Rear Surface Coating

Required

UV Transmission cutoff

> 380 nm, less than 1% UVA and UVB

 

 

Unique Semi-Visible Mark:  K+P

 

Blank Size:        74mm diameter blanks decentered 3mm

Effective diameter is 80mm.

 

Base Curves:     1.50, 3.25, 5.00, 7.00

 

Power range:              -7.50 to +6.00

Add range:        1.00  to 3.00 in .25 Diopter steps.

 

Thicknesses:      We recommend a minimum center thickness of 1.5mm and a minimum
edge of 1.3mm.  To ensure proper frame retention, low power lenses may require greater thickness.  Special frame mounts, such as grooved lenses, should have a 2.3mm edge thickness with the groove centered on the edge.

 

 

 

Text Box: InstaShades lenses are designed with MultiMatrix™ technology. The photochromic materials are contained in approximately the front 0.8mm of the lens. The material behind the first 0.8mm provides the optical properties. The mechanical properties of the lenses depend on 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 InstaShades PolyClear Lens - Dimensions

Nominal Curve

True Curve

Radius mm

SAG at 50mm

Nominal Concave

Edge Thickness

Center Thickness

1.50

1.48

358.108

0.87

6.00

14.10

8.80

3.25

3.12

169.872

1.85

6.00

13.00

10.00

5.00

5.07

104.536

3.03

6.00

9.00

8.80

7.00

6.86

77.259

4.16

6.00

9.80

12.30

 

 General:
Processing of the KODAK Precise InstaShades PolyClear lens is similar to that of standard polycarbonate lenses.  Generator, edger wheels, and fining pads designed for polycarbonate must be used.  If you have questions on processing the KODAK Precise InstaShades PolyClear lenses, please contact our Technical Services department at 800 759-4630.

 

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.

 

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+P 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/Remarking the Temporary Reference Marks:

The KODAK Precise Lens markings may be removed by wiping the surface with alcohol.  If AR coating the lens, wipe the area a second time to make sure all residue is removed.  Never use acetone on PolyClear lenses.

 

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.

 

Fining and Polishing:

Processing the KODAK Precise InstaShades PolyClear lens is the same as processing other polycarbonate lenses. Safety bevel the lens before fining to 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.  Perform a stock removal test, using your process to most accurately establish the correct surfacing thickness allowance.  We strongly recommend fining pads with eight or more petals be used for curves over 9.00 diopters.  This can prevent aberrations and score lines.

 

Back Surface Coating:

Since the processed back surface of the lens is standard polycarbonate, it must be hard coated with a polycarbonate compatible coating.

 

Edging:

Edge this lens using techniques for polycarbonate lenses.  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.


For rimlon or grooved lens type processing, the groove should be placed so it is contained within the rear polycarbonate portion of the lens.  For plano, plus, or up to -0.50D lenses, the edge thickness must be set to at least 2.3mm and the groove positioned at the center of the edge.  For minus powers below -0.50, placing the groove  so that it is one third of the distance from the front surface and two thirds of the distance to the back surface will ensure the groove is within the polycarbonate material.

 

Drilling:

InstaShades polycarbonate 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.  The drilled portion of the lens may fail over time if the drilling was done improperly.  Please see TIPS 242, “Making Stronger Three-Piece Eyewear,” for our recommendations on drilling and screw torque measurement techniques.  We recommend no greater than 8 inches ounces of torque be applied to nuts of three-piece frames.

 

AR Coating:

Multi-layer AR coatings can be applied to KODAK Precise InstaShades PolyClear lenses.  Be sure that your AR coating is compatible with your backside coating.  Include impact testing for lenses AR coated and sold by your lab.  This lens has a front surface factory-applied hard coating which is designed to be compatible with most AR coating processes.  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.  This coating is applied in the mold and not considered strippable.

 

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.

 

The lens corridor from the fit point to the full add power measures 17mm, so we recommend a minimum fitting height (sometimes called the segment height) of 20 mm. Use 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 Precise Lens Dispensing Aid (part number K763-578.).  Verify that the blue shaded area is contained within each eye of the frame.

 

Kodak is a trademark of Kodak, used under license by Signet Armorlite, Inc.

InstaShades is a registered trademark and Precise, Concise, PolyClear, and MultiMatrix are trademarks of Signet Armorlite, Inc.

 

KODAK Precise InstaShades PolyClear

Base Curve Selection Chart