Eye on Equipment
Demystifying Rimless Lenses
By Susan P. Tarrant

Rimless eyewear has become more popular than ever, and because of high-end lens styles and treatments usually associated with the eyewear, it has become a revenue center. But edging and drilling three-piece mounts is not without challenges. Here, edging and drilling experts provide helpful tips.

QUESTION: How can I achieve the best appearance when grooving a thicker, high-powered rimless lens?

Rimless eyewear, such as Charmant's i-NOVA style 10100, builds revenue

ANSWER: For the best appearance, one technique is to place the groove more toward the front of the lens instead of mid-lens. This helps to minimize the thick appearance of the lens.

With a table groover, it takes a skilled operator to achieve the best placement since the device does not measure the lens thickness or curve. In contrast, a patternless edger with an integrated autogroove function can do this automatically. These edgers have built-in software that's programmed to measure the shape, curvature, and thickness of the lens to automatically determine the best placement of the groove from an aesthetic viewpoint. It's also important for an automatic autogroover to have an override feature that allows the operator to manually adjust the groove placement forward or backward if desired, as in the case of a lens with varied thickness or if the patient has a cosmetic preference.

--Rob Greco, New York metro sales manager, Briot-Weco USA

QUESTION: When prepping to edge a three-piece mount, do I need to handle my patternless edger differently than when edging a framed lens?

ANSWER: It is important, when preparing for a rimless job, that your tracer knows the job is rimless. If you program your edger specifically for a rimless job, it knows how to adjust itself properly at the beveling stage. Setting your automatic edger for rimless will ensure a more accurate lens sizing.

--Susan Polson, director of marketing, National Optronics

QUESTION: When edging a semi-rimless lens, I have a hard time getting the cord to fit properly and securely in the groove. Am I doing something wrong?

ANSWER: Instead of the nylor cord that's used with lenses that are going into full-framed eyewear, semi-rimless lenses are wrapped by a thin metal cord. Since it is thicker than nylor, this metal cord requires a thicker and deeper groove.

My technique has been to use a caliper to measure the width and depth of the wire, and then to indicate that measurement in the "rimless grooving" mode of the automatic edger. If the proper measurements are input, the edger will do a wonderful job.

--Franco Aluigi, product manager, Santinelli International

QUESTION: My rimless lenses look crooked when assembled. Why?

ANSWER: If axis is off, rimless eyewear is going to look crooked. You will be able to see it's off. Maintaining axis control will alleviate this problem. Rimless eyewear needs even tighter axis control in the edging and drilling stages--sometimes even tighter than what's prescribed. Be sure you have an edger that has good axis calibration and variable clamping pressure. Rimless lenses require less pressure--variable clamping pressure would allow you to select a fragile setting that creates less torque.

Another tip: Use "free blocks" that don't use leap pads. Try the wax blocks that are heated and mounted to the lens.

--Marc Okrant, group product manager, Gerber Coburn