Strong prescriptions are always a challenge. Patients are concerned with how their glasses will look, while dispensers need to focus on providing the best optics along with superior cosmetics. Today's smaller frame styles naturally lend themselves to more eye-pleasing eyewear, but there are other tricks of the trade that can be incorporated beyond a smaller eyesize. Here the experts share their insider knowledge about making high Rx's look their best.

EYES WIDE OPEN

PROBLEM: High plus lenses cause the wearer's eyes to appear huge

SOLUTION: Try an aspheric design instead of a regular lens. Aspheric lenses have a flatter front curve, so they won't have a "fishbowl" effect where the patient's eyes look ten times bigger than they really are.

-Dan Kurban, service technician, LOH Optical

SLIMMING DOWN

SOLUTION: Prism thinning can be programmed into most machines if it doesn't automatically come up during the surfacing process. The higher the Rx, the more prism thinning needs to be done to the lens in order to come out with a thinner finished blank. If you order progressives from the surfacing lab, you can request that they do prism thinning on a high-Rx job.

-Kristhian Cruz, technical support, Briot

WALKING A THIN LINE

PROBLEM: Strong prescription lenses look thick in frames with thin eyewires, even in small eyesizes

SOLUTION: When you're putting a high Rx into a thin frame, put the bevel close to the front in order to keep the lens from protruding out in the front. It looks cleaner this way. On the other hand, with a thicker zyl frame, move the bevel back so that the eyewire hides some of the lens thickness.

-Kent Jones, technical services, WECO International

EDGING OFF THICKNESS

PROBLEM: The edges of high minus lenses are unattractive

SOLUTION: On a minus lens, the rear portion of the lens always appears very thick. By rolling the edges on a hand edger, you can eliminate some of the thickness on the outer edges so that the back side of the lens appears thinner. Also, polish the edges so that they appear clear and less noticeable.

-Bill Galindo, president, ODI/Topcon

CR 39 PROBLEMS

PROBLEM: High minus lenses are too heavy and thick in CR 39

SOLUTION: More and more lens materials with higher indices of refraction are becoming available all the time. Choose the highest index available for the thinnest possible lenses. Also, the fabricating lab will do the thinnest center thickness (CT) possible. In a 1.66 IOR material or polycarbonate, it's possible to take a lens down to as little as a 1.0 mm CT. Mid-index materials will wave up at a 1.0 center-they go down to between a 1.5 and a 1.8 mm CT. With CR 39, labs need to stick to a 2.0 to a 2.2 mm CT.

-Stuart Watson, training director, National Optronics

MODIFY THE BASE CURVE

PROBLEM: Surfaced lenses come out too thick

SOLUTION: Trace the frame first and feed that information into the surfacing layout system. If you know the size of the frame, you can manipulate the edge thickness and center thickness of the lens by entering specific values for them on the surfacing side. Also, by selecting a different base curve (BC), you can modify the way the lens is generated. If you go to a higher BC on higher minus lenses, you will come out with a lens that has thinner edges. Just be certain that the patient can tolerate the BC change before modifying it.

-Michael Urban, product manager, Gerber Coburn

CHOOSING THE RIGHT FRAME

PROBLEM: Strong lenses don't work well in certain frames

SOLUTION: The Rx is king. All aspects of dispensing have to work together, so you need to look at the prescription first, then choose the frame. Choose a frame with a thicker eyewire to disguise the thickness of the lens, and opt for lens treatments such as roll and polish and anti-reflective coating as well in order to make the lens look less obtrusive.

-Tom Fefer, western regional manager, Santinelli International

LOOKING GOOD

PROBLEM: Even in smaller frames, high Rx's don't look good

SOLUTION: Keep to frames that have rounded edges as well as being small. If frame shape is squared off, the corners tend to give thick portions to the lenses. Also, take advantage of high-index materials. If price is a consideration for the patient, sacrifice an expensive frame for higher index lenses. Keep in mind that some high-index glass lenses might be thinner than plastic. In polycarbonate, the visual acuity will be better in high minus lenses than in high plus.

-Tracey Morrison, sales and marketing, Optical Works Corp. EB

Got a question you'd like answered in a future "Eye on Equipment" column? Send it now!