TIPS NO: 252
Revision: B
Date: June 2010

KODAK Precise^® Progressive Lenses in Trivex^®
Product Specifications and Fitting Guide

PURPOSE: The following information will assist you in processing Kodak Precise Progressive Lenses in Trivex.

SUMMARY OF CHANGES: Certain Dimension Specifications have been changed.

Characteristics	KODAK Precise Lens in Trivex
Refractive Index	1.530 ref d
Dispersion Value (Abbe)	44.0
Density	1.11
Chemical Resistance	Excellent
Machinability	Excellent
Rear Surface Coating	Recommended
Scratch Resistant	Front side coated
UV Blockage	100% UVA and UVB

UNIQUE SEMI-VISIBLE MARK: K+△
BLANK SIZE: 75mm & 80mm diameter blanks decentered 3mm Effective diameters are 81 and 86mm, respectively.
BASE CURVES: 1.50(75MM), 3.25(80MM), 5.00(80MM), 7.00(80MM)
POWER RANGE: -10.00 TO +4.50
ADD RANGE: -1.00 to 3.00 in .25 Diopter steps.
THICKNESSES: We recommend a minimum center thickness of 1.2mm, or 1.4mm if AR coated.

KODAK Precise Progressive Lens in Trivex - DIMENSIONS

NOMINAL CURVE	TRUE CURVE	RADIUS MM	SAG at 50MM	NOMINAL CONCAVE	EDGE THICKNESS	CENTER THICKNESS
1.50	1.51	350.993	0.89	3.00	13.1	12.5
3.25	3.22	164.596	1.91	6.00	12.1	8.9
5.00	5.23	101.338	3.13	6.00	6.7	7.1
7.00	7.05	75.177	4.28	6.00	6.7	10.6

GENERAL:
Trivex combines aspects of standard plastic and polycarbonate. Standard surfacing procedures for polycarbonate progressive lenses should be used with Kodak Precise Lenses in Trivex, but bear in mind that Trivex has a refractive index of 1.530. If you have questions regarding these lenses, contact Technical Services at 800-759-007

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 provide the necessary specifications. Please forward us the contact name and phone number of your software vendor.

LAYOUT:
All surfacing should be done in relation to the prism reference point located on the 180 line. 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 directly above the prism reference point dot. This improves the accuracy of positioning the patient's pupil to the center of the corridor. 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.

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+△” 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:
Kodak Precise Lens markings may be removed by wiping the surface with alcohol or other standard polycarbonate lens mark removing solvents. These marks are designed to withstand all processing procedures. They provide an easy way to verify the edging accuracy and must be removed before 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 Trivex is similar to polycarbonate 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 flares and wrinkles.

EDGING:
Edging Trivex is slightly different from other materials. This product is known to create a good amount of dust when dry edged, so we advise special dust collection methods be implemented. Dry edging at slow speed with polycarbonate settings are preferable and Axiom™ wheels are specifically designed for Trivex. Trivex accepts edge polishing very well. 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:
Kodak Precise Lenses in Trivex are excellent for drill mounting. When drilling, do so at a speed slower than standard polycarbonate.

AR COATING:
Multi-layer AR coatings may be applied to Kodak Precise Lenses in Trivex. Because lens impact resistance is reduced by AR coatings, we recommend a 1.4mm minimum center thickness and a backside coating that will enhance the impact resistance capability. Be sure that your AR coating is compatible with your backside coating. Include impact testing 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.

TINTING:
Kodak Precise Lenses in Trivex may be tinted after an appropriate back side coating has been applied, but the results will vary with the type of coating used. Tint tank temperatures should be 175°F to 185°F, and the lenses inspected frequently for proper tint absorption to avoid over-tinting.

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 minimum fitting height (sometimes called the segment height) is 17mm.

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 357-893). 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 Kodak, used under license by Signet Armorlite, Inc.
Concise and Precise are registered trademarks of Signet Armorlite, Inc.
Trivex is a registered trademark of PPG Industries.