TIPS NO: 257
Revision: 00
Date: August 2007

KODAK Precise Short™ Progressive Lenses in
in PolyClear^® Product Specifications and Fitting Guide.

PURPOSE: The following information will assist you in processing KODAK Precise Short Progressive Polycarbonate Lenses.

Characteristics	KODAK Precise Short Lens in PolyClear
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
Scratch Resistant	Front side non-tintable coating
UV Blockage	100% UVA and UVB

UNIQUE SEMI-VISIBLE MARK: K_SP
BLANK SIZE:78mm diameter blanks decentered 3mm Effective diameter is 84mm.
BASE CURVES: 2.00, 4.50, 5.50, 7.50
POWER RANGE: -10.00 TO +6.00
ADD RANGE: 1.00 to 3.00 in .25 Diopter steps.
THICKNESSES: We recommend a minimum center thickness of1.5mm.

KODAK Precise Short Progressive Lens in polycarbonate - DIMENSIONS

Nominal Curve	True Curve	Radius mm	SAG at 50mm	Nominal Concave	Edge Thickness	Center Thickness
2.00	2.04	259.804	1.21	6.00	13.0	8.0
4.50	4.51	117.517	2.69	6.00	8.7	8.0
5.50	5.52	96.014	3.31	6.00	8.0	9.0
7.50	7.54	70.292	4.60	6.00	8.0	12.5

GENERAL:
Processing of the KODAK Precise Short PolyClear Lens is similar to that of standard resin with a few exceptions. Generator and edger wheels designed for polycarbonate material and two-step fining pads used for polycarbonate must be used.

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 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 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 “KSP” 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 provide an easy way to verify the edging accuracy and must be removed before tinting. These marks are designed to withstand all processing procedures. They may be removed by wiping the surface with alcohol. Never use acetone on polycarbonate lenses. If AR coating the lenses, make sure all residue is removed by wiping the area a second time.

To re-mark the lens, first locate the semi-visible markings, specifically the “+” symbols engraved along the 180° 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 KODAK Precise Short polycarbonate 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.

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:
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.

TINTING:
The KODAK Precise Short Lenses in polycarbonate may be tinted after an appropriate back side coating has been applied, but the results will vary with the type of coating used. Neutralize by using only products designed for polycarbonate. Standard neutralizers will damage the lens.

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 13 mm. The frame shape, frame PD and patient’s PD affect how much of the full addition reading area falls inside the frame. To ensure these variables will not limit near vision, lay the frame (with the fit point marked) onto the KODAK Precise Short 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.
Precise Short is a trademark and PolyClear is a registered trademark of Signet Armorlite, Inc.