ask the labs
Outdoor Activities and Toughness
by Karlen McLean, ABOC, NCLC
FOGGING UP
Q I have a patient who needs anti-fog lenses. What are my options?
A There are several good anti-fog wipes available; there is no one market leader. All anti-fog wipes require frequent reapplication. Some plano safety lens products advertise that the lenses are anti-fog, but require the use of a ‘rejuvenator’ to restore the anti-fog properties.
— Bob Gustin, vice president of business development, Walman Optical, Minneapolis, Minn.
SURF'S UP
Q What kind of eyewear can you recommend for surfing?
A There are several companies out there that provide plano and Rx-able surfing eyewear, including SeaSpecs and Silverfish. The styles vary from full wrap frames to goggles. At least one company offers oversized goggles with vents that allow circulation and drain water out.
I surf three to five days a week and have seen everything out there, from goggles to eyewear with tight sports straps, contact lenses, and no eyewear. If you're extreme surfing or kite surfing, or get into the washing machine, anything you're wearing is likely to come off in big water. But many people, including me, choose to wear sunwear to protect their eyes.
We're seeing 20-year-olds with pterygiums now, and quite a few surfers I know have this eye pathology and are very protective of their eyes because of it. We Rx lenses in primarily Trivex or SR-91 materials for high impact-resistance and visual clarity, always polarized, and with super hydrophobic coating.
I wear, and we recommend, polarized lenses with higher transmission levels because surfers generally need to be able to read the contrast on the ocean and between the waves so they can clearly view bumps in the wave signaling a good ride to catch.
Most surfers go out before 10 a.m. and after 5 p.m., so the intensity of the bright sun—requiring a dark lens—isn't as strong.
— Richard Wilhelm, founder and owner, West Coast Lens, Huntington Beach, Calif.
| Cracking up |
|---|
| Q When I process polycarbonate lenses, they often crack. Why? How can I prevent this from happening? A If there is too much material being taken off at the generator, poly will craze in the center of the lens. The craze is actually a group of small cracks that occur due to pressure and heat. This can also occur when aggressively edging poly. Cracking will occur in the lens center where the mounting pad is located. When mounting poly, care must be taken to avoid clamping the lens too tightly in the frame, especially a metal frame. Over time this steady pressure will cause the poly to crack. While poly protects well against fast traveling hazards, anything that is slow that creates pressure on poly can be a problem. — John Young, president, COLTS Laboratories, Clearwater, Fla. |
If you have a question you'd like to have answered in Ask the Labs, send it to Karlen McLean. Email: 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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