troubleshooting tips
How to make thin nice
Karlen McLean, ABOC, NCLC
Thin and light are the two lens features consumers ask for the most. But getting thin lens results can take a lot more than just writing “thin as possible” on an Rx. Here's some background so you don't skate on thin ice when it comes to thin lenses.
GETTING THE SKINNY
Q I feel that our availability in getting the thinnest possible lenses has regressed with lens manufacturers closing in their parameters on high-definition lenses and newer technology. Is this true?
A Different algorithms in the software labs and manufacturers used to design and fabricate free-form lenses can impact the resulting lens thickness profiles. Several products can actually come out thinner than when using traditional design and production means. Try sampling multiple sources before concluding that all newer lenses are thicker than conventional products. It's a good idea to tour labs and take advantage of their education opportunities.
— Brad Main, director, training and technical resources, Hoya Vision Care, North America, Lewisville, Texas
CONFIRMATION SITUATION
Q I've always assumed that my lab provides me with the thinnest product available when I ask for it. What should I do if I have to check this or prove it to a patient?
A This is a tricky situation because it speaks to the level of trust in the customer-lab relationship. We often run the job through the computer under different scenarios. For example, we key in the job first as a 1.0 CT poly, then a 1.67, and finally a 1.74, and provide the customer with the resulting thickness data and prices.
In most cases, the highest index lens will be the thinnest, but may not be worth the extra price. A lens may be 0.2mm thinner in a 1.74 versus a 1.67, but the price difference may be $20 or $30 to the ECP, so we leave the decision to the customer. Giving customers the data up front allows them to make an educated decision.
— Jason Mansuy, vice president operations, Vision Craft, Walled Lake, Mich.
| THIN PLUS |
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Q What's the best way to ensure that I get thin (reduced) center thickness with high-plus lenses? A Follow these tips: 1) Select a frame with a frame PD that's close to the patient's PD. Eye size plus DBL gives you the frame PD. If the eye size is 52mm, and the DBL is 18mm, the frame PD is 70mm. If the patient's distance PD is 64, there will be a difference of 6mm, or 3mm of decentration per eye. Keeping decentration to 3mm or less per eye is helpful. 2) Stay away from drill or groove mount frames. The lab has to add lens thickness so the edge of the lens is thick enough for these frame designs. 3) High-index lenses will reduce the thickness over, say, CR39. 4) Aspheric lens designs will flatten lens curve and be more cosmetically appealing. — Chris Brown, Optical Help Desk, Walman Optical, Minneapolis |
If you have a question you'd like to have answered in Ask the Labs, send it to Karlen McLean. E-mail: Karlen.McLean@WoltersKluwer.com. An archive of past Ask the Labs columns can be found on the Eyecare Business website at www.eyecarebusiness.com.
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