TIPS NO: 230
	Revision: A
	Date: Aug 2003

Purpose:
The following is provided for fitting and processing KODAK Precise Progressive Polycarbonate Lenses.

Summary of changes: The back curves and thicknesses were changed on the 1.50 and 3.25 bases.

The new OPCs are:
1 base Precise = 0103821195 - 0103821443
3 base Precise = 0103821468 - 0103821716

replacing the following OPCs:
1 base Precise = 0103733465 - 0103733713
3 base Precise = 0103733739 - 0103733986

General:
Processing of the KODAK Precise polycarbonate lens is similar to that of standard resin with a few exceptions. Generator and edger wheels designed for polycarbonate material and fining pads designed for polycarbonate must be used. If you have questions on processing the KODAK Precise polycarbonate 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 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 polycarbonate 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 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:
Multi-layer AR coatings can be applied to KODAK Precise 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. 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:
Polycarbonate material will not absorb tint. Therefore, in order to tint, a tintable backside coating must be applied. Conventional hard resin tints are acceptable. Neutralize by dipping the lens in a non-citrus liquid detergent and water. 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 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.