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New ANSI Standards

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his is very important information for eyecare professionals with in-house processing especially as the American National Standards Institute (ANSI) earlier this month approved a series of updates to the Z80.1 standard for prescription spectacle lenses. Overseen by the Z80 Accredited Standards Committee (ASC) for Ophthalmic Optics, which consists of 18 voting organizations and more than 100 experts, these changes are designed to increase the durability and quality of lenses.

The Z80.1 standard serves as a guideline for both eye care professionals with in-house processing and optical laboratories to follow prior to the delivery of finished eyewear to the patient. It applies to the processing of all prescription ophthalmic spectacle lenses in edged or assembled form. Relevant optical specifications and tolerances of this standard also apply to uncut lenses supplied by an optical laboratory to be used in filling a specific prescription.

The revised Z80.1 standard includes updates to:

* Measurement of transmission power: In 1995, Z80.1 adopted the ISO method to measure specified power which is based on the meridian of highest power. The 2010 Z80.1 revision reverts to the sphere and cylinder method without a change in tolerances.

* Use of compensated power: The use of compensated power for the as-worn position was expanded to include both distance power and add power. The power tolerances are applied to the compensated values and not to the prescribed prescription.

* Lens durability: Lens durability requirements were added from two new ISO standards – specifications and test methods for anti-reflective coatings from ISO 8980-4 and minimum requirements for spectacle lens surfaces claimed to be abrasion resistant from ISO 8989-5.

* Lens abrasion resistance: The new requirement for lens abrasion resistance applies only if the lens supplier claims it. The requirement is that the lens resists abrasion at least as well as uncoated hard plastic (CR-39) as determined by a rubbing test.

* AR coating: The new AR coating requirements assess durability by subjecting the lens to mechanical rubbing, high humidity and UV radiation. After the sequence, the lenses are inspected to determine if delamination of the AR coating has occurred. The maximum reflectance of an AR coated surface was also changed to 2.5 percent.

“The changes to the Z80.1 standard are significant to the optical community. For one, lens power measurement is now done using the method most familiar to labs and ECPs as the ISO international method is no longer used,” said The Vision Council’s Ken Wood, secretariat for ASC Z80. “The other additions covering lens abrasion resistance and AR durability are the first such requirements in the US market and establish a minimum level of performance that can protect both the patient and the ECP by barring poor performing products.”

The 2010 ANSI Z80.1 standard for prescription spectacle lenses can be purchased at www.webstore.ansi.org. This standard does not apply to products covered by American National Standard Requirements for Nonprescription Sunglasses and Fashion Eyewear, ANSI Z80.3-2008.

For more information on the changes to the Z80.1 standard, please contact Amber Robinson, The Vision Council manager of member and technical programs, at (703) 740-1094 or at arobinson@thevisioncouncil.org.

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