TIPS NO: 260A
Revision: A
Date: July, 2008

KODAK Precise Short™ Progressive 1.67 Lens

Product Specifications and Fitting Guide

PDF Version: TIP_260_KPS_167_(L) (120 kb)
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PURPOSE: The following information will assist you in processing KODAK Precise Short Progressive 1.67 Lenses.

Characteristics	KODAK Precise Short 1.67 Lens
Refractive Index	1.666
Dispersion Value (Abbe)	32.0
Density	1.35
UV Transmission Cutoff	402nm
UV Blockage	100% UVA and UVB
Chemical Resistance	Excellent
Machinability	Excellent
Rear Surface Coating	Required
Scratch Resistant	Yes, tintable

UNIQUE SEMI-VISIBLE MARK: KS
BLANK SIZE: 75mm diameter blanks decentered 3mm. The effective diameter is 81mm.
BASE CURVES: 1.00, 2.00, 4.50, 5.50, 7.50
POWER RANGE: -13.25 TO +6.00
ADD powers: +1.00 to +3.00 in .25 Diopter steps.
THICKNESS: We recommend a minimum center thickness of 1.5mm.

KODAK Precise Short Progressive 1.67 Lens - DIMENSIONS

Nominal Curve	Diameter	True Curve	Radius mm	SAG at 50mm	Nominal Concave	Edge Thickness	Center Thickness
1.00	75	1.00	530.00	0.59	9.33	18.9	6.8
2.00	75	1.99	266.332	1.18	4.01	10.7	8.8
4.50	75	4.53	116.998	2.70	4.01	7.9	9.4
5.50	75	5.57	95.153	3.34	6.30	9.9	10.00
7.50	75	7.63	69.463	4.64	6.30	8.8	12.3

GENERAL:
Standard surfacing procedures for CR-39^® progressive lenses should be used with the KODAK Precise Short Lens, but bear in mind that 1.67 high index has a refractive index of 1.666. If you have questions regarding these lenses, 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 Short 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.

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 3mm. 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. If you use an automated lens blocker, such as the Gerber Coburn 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 or 4mm up.

SEMI-VISIBLE MARKINGS
KODAK Precise Short Lens markings have a “+” at the nasal and temporal sides along the 180º axis line. Approximately 3mm below the nasal “+” you will find the “KS” 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 Short 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 Short verification chart for the final re-marking.

FINING AND POLISHING:
Processing the 1.67 high index 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 flares and wrinkles.

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.

AR COATING:
Multi-layer AR coatings can be applied to KODAK Precise Short Lenses. Because lens impact resistance is reduced by AR coatings, 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:
The 1.67 index lens material tints similarly to other high index lenses using the normal materials and methods. Prolonged immersion in tint tanks may cause warpage. After tinting, clean the lenses with alcohol or acetone to remove excess dye from surfaces. If you decide to tint the lens, test a sample lens first. Tint at lower than normal temperatures.

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 1.0mm.

We recommend a minimum fitting height (sometimes called the segment height) of 13mm.

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 Short 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.
Precise Short is a trademark of Signet Armorlite, Inc.
CR-39 is a registered trademark of PPG.