General:
Standard surfacing procedures for CR-39^® progressive lenses should be used with the Kodak Concise lens, but bear in mind that 1.56 EvoClear has a refractive index of 1.557. 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 Concise 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 Concise Lens markings have a "+" at the nasal and temporal sides along the 180º axis line. Approximately 3mm below the nasal "+" you will find the "KcI" 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/Re-marking the Temporary Reference Marks:
The Kodak Concise 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.

Layout:
All surfacing should be done in relation to the prism reference point located on the 180º 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 2.0mm above the prism reference point dot. 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 -2mm down (2 up), 2.7mm in.

Fining and Polishing:
Processing the 1.56 EvoClear 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 wrinkles in the pads which can result in an aberrated lens. Should you experience unusual reject causes, retain samples and contact Technical Services for assistance.

Edging:
Layout for edging should be done in reference to the fitting cross located 2.0mm above the MRP. The fitting cross is placed at the point of the specified segment height and monocular PD.

Drilling:
InstaShades 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.

AR Coating:
Multi-layer AR coatings can be applied to Kodak Concise Lenses. Because lens impact resistance is reduced by AR coatings, we recommend a 1.8mm minimum center thickness and a backside coating that will enhance the impact resistance capability. This minimum thickness recommendation is based on surfacing to no less than 1.8 mm and using UltraOptics UVNV backside coating prior to applying AR coating. Other back surface coatings may enhance or reduce the impact resistance.

Tinting:
We do not recommend tinting InstaShades lenses. Doing so will void any factory warranty.

Neutralizing:
Our test results show the KODAK InstaShades 1.56 EvoClear Lens can be damaged when using tint neutralizers designed for CR-39. Use a neutralizer designed for polycarbonate or high index materials. Use of hot soapy water is safest.

Thermal Stability:
The InstaShades 1.56 EvoClear Lens material has a similar level of heat sensitivity as other high index materials. The lens can flex if heated under pressure. To prevent warpage, avoid heating the lens over 130°F while it is under pressure including from frame or clamping while coating. Warpage can cause a plastic lens to fit loosely in the frame. If the lens should become warped, heat without pressure to allow the lens to return to its original shape.

Fitting and Frame selection:
Our minimum fitting height (sometimes called the segment height) guideline is 17mm, based on the 12mm corridor length. The measurement includes 2mm above the reference dot where the fitting cross is marked, as well as 3mm of clear area below the full addition location. Minimum fitting height values are completely Rx and frame dependent. The frame shape and patient’s monocular PDs will affect this minimum fitting height, which is measured from the lowest point of the frame and not the lowest point of the frame where the reading area falls. Illustration 1.0 shows that the near zone may not fall inside the frame for certain frame and monocular PD requirements.