HANDS ON - ask the labs
by Karlen McLean, ABOC, NCLC

GET IN THE GROOVE

Q Can I utilize high index lenses when patients opt for a screwless drill mounting?

A Generally, we fabricate lenses for a groove-mount rimless frame by maintaining a 2.0 to 2.2 edge thickness.

If we try using high index lenses with 1.8 edges, they invariably flake, either during fabrication, at the dispensing table, or once the patient takes them home.

We've also found that it's important to clean all the leftover lens material from the grooves. If we don't, the leftover debris can cause unevenness and flaking.

The most effective cleaning method, in our experience, is to use a toothbrush to clean out the grooves manually, then follow-up with ultrasonic cleaning.

We're more comfortable using a groove-type rimless than a clip-type rimless for high index work, but we strongly encourage using polycarbonate, Trivex, or specialized 1.67 material for rimless jobs due to safety issues and Duty to Warn concerns.

— Mike Lynch, vice president operations, and Art Waite, sales manager, Winchester Optical,
a group with four locations in New York and Pennsylvania

Q Under what circumstances should I roll the edges of a lens? And in what situations shouldn't I roll the lens edges?

A We recommend rolling the edges only in situations where there is trouble with temple closure, which is typically seen on a high minus lens.

Take care when rolling edges on a high index lens, because rolled edges can cause more chromatic aberrations, which exhibits reflections. If the person has problems with reflections, rolling isn't the way to go.

It is also harder to roll a high index lens. These lenses have to be machine rolled, which causes them to come out looking more like a facet than a true roll.

If it's the patient's preference and it cosmetically enhances the lenses, remember that prettier eyewear has better patient acceptance.

— Bob Kosmach, lab manager, Sunstar Optical Company,
Las Vegas and Reno, Nev., and
Salt Lake City, Utah

COLORFUL CREATIONS

Q What tint colors would you recommend for my in-office tinting unit so that we can cover the basics and also have a basis for custom colors? We have six tint pans available.

A We recommend gray, brown, blue, pink, yellow, and green. Each can be used on its own as a popular tint in solid or gradient form, and each can be customized by blending with other colors to individual patient preferences. This tint grouping also lends itself to the easy creation of double gradient hues, such as gray on the top and pink on the bottom. When creating your own custom colors, such as turquoise or magenta, it's best to practice on demo lenses first, then tint the patient's lenses after practicing and getting the color right on the demo lens.

— Steve Seibert, president, Three Rivers Optical, Pittsburgh

If you have a question you'd like to have answered in Ask the Labs, send it to Karlen McLean. Fax: 215-643-1705. E-mail: mcleank@boucher1.com. An archive of past Ask the Labs columns can be found on the Eyecare Business Website at www.eyecarebusiness.com.