Ask The Labs
By Joseph L. Bruneni

MISUNDERSTANDING REGARDING INDUSTRIAL SAFETY LENSES

Q In a story about Trivex lenses in the May issue of Eyecare Business, an optician is quoted as stating, "It (Trivex) also works well for kids and safety glasses because we are able to get away from the 3.0 centers." Is it legal to dispense Trivex lenses for safety glasses with less than 3.0mm centers?

A Similar in impact resistance to poly, Trivex lenses for children can be legally dispensed in conventional thickness. Prescription lenses for industrial safety glasses in any material are required to be 3.0mm at their thinnest point. A revised Z87 standard is currently under consideration to permit prescription lenses in polycarbonate or Trivex to have 2.0mm centers. Until that revised standard is issued, Trivex lenses for industrial safety are required to be 3.0mm.

--Polycarbonate Lens Council

ANOTHER WAY TO REMOVE HARD WATERMARKS FROM LENSES

Here is an additional answer to the following question, which was featured in a previous Ask the Labs column.

Q What should we recommend to remove what appears to be a thin layer of hard water deposits, maybe calcium carbonate, from a patient's polycarbonate eyeglasses?

A For removing hard water deposits, common here in Houston, I wet the lenses with an inexpensive white vinegar for a few minutes and then rinse the lenses under the faucet.

Take care to not use a towel or anything to dry the lenses before they are rinsed. The hard water scales can get loose on the lens surface and scratch the lens if they haven't been rinsed off.

--Fernando J. Rueda, Houston, Texas

MORE ON SCRATCH COATINGS AND LASER MARKINGS

A The filling in of laser etchings with scratch coating was a problem when PALs were made without scratch coating and labs applied the coating. Today, there aren't enough PALs made without scratch coating to worry about.

Also, few scratch coatings will stick to a lens that is already scratch-coated, so applying scratch coating to fill in a mark probably isn't an option.

--Jim Grootegoed, Walman Optical

Problem in New Jersey

Q Is it a law that children under a certain age must use polycarbonate lenses in the state of New Jersey?

A We wish we could help you, but we're not up-to-date on state laws. We would be surprised if that's the case, however, and believe we would know if it were the law. If you're in an optometric office, you might check with the American Optometric Association. They generally keep up with state laws regarding optical services.

--Polycarbonate Lens Council

If you have a question you'd like to have answered in Ask the Labs, send it to Joseph L. Bruneni. Fax: 310-533-8165. Phone: 310-533-4975. E-mail: joe@bruneni.com.  Or mail questions to: Vision Consultants, 2908 Oregon Court, #I-2, Torrance, CA 90503. An archive of past Ask the Labs columns can be found on the Eyecare Business Website at www.eyecarebiz.com.