ask the labs
Heights & Rights
by Karlen McLean, ABOC, NCLC
DIFFERENT HEIGHTS
Q If a patient has different pupil heights—say 3mm to 4mm difference—with a frame that is virtually non-adjustable, what's the best way to measure and order progressive addition lenses for them?
A Definitely use a pupilometer to get the horizontal measurements. Then dot the optical centers for vertical measurements.
Compare the differences and accurately mark down the different heights. You might even want to consider taking the measurements twice for assurance.
When placing the order with the lab, make thorough notes as to how and why you're ordering the heights the way you are so that the order doesn't bounce back.
— Robert Scherer,
president,
Premium Optics,
Fort Lauderdale, Fla.
BIG IMPACT
Q I heard something recently about the last processor being responsible for impact testing lenses. Does responsibility extend to dispensers who do edging in their in-office labs?
A Yes, dispensers who edge can be held liable.
In fact, defendants in a strict liability or product liability lawsuit can be held liable even if not negligent due to "social policy."
Responsibility has moved from manufacturers to the last processor due to the influence of coatings and edging.
The FDA states that, "a person that put the lens in the form ready for its intended use or who alters the physical or chemical characteristics of the lens by such acts as grinding, heat treating, beveling, or cutting (edging) is responsible for impact testing."
Because impact testing can be difficult and expensive for dispensers, we recommend purchasing uncuts from a certified lab that uses a patented impact-testing program.
— John Young, president,
COLTS Laboratories,
Clearwater, Fla.
| ACETONE REACTION |
|---|
| Q What are the cautions regarding using acetone on polycarbonate lenses? A Acetone should not be used on polycarbonate lenses. Even a slight amount of acetone on a poly lens can cause the lens to crack and craze. Acetone can be used on all types of lenses provided that they have a hardcoat on them. If poly is uncoated, then acetone will ruin the lens. Even if poly is hardcoated, acetone can still damage the lens by seeping under the hardcoat after the lenses are cut and/or drilled. |
| —Stuart H. Blankman, OD, New York, and Brent K. Hammer, optician, Heritage Vision Center, Hattiesburg, Miss. |
If you have a question you'd like to have answered in Ask the Labs, send it to Karlen McLean. E-mail: mcleank@lwwvisioncare.com. Fax: 215-643-1705. An archive of past Ask the Labs columns can be found on the Eyecare Business Website at www.eyecarebusiness.com.
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