HANDS ON - ASK THE LABS
by Karlen McLean, ABOC, NCLC

POLARIZED PROTOCOL

Q Are there situations where polarized lenses aren't recommended?

A Polarized lenses can adversely interact with today's digital displays, for example, gas pump displays, dashboard gauges, and cellular telephone readouts. Certain professions and environments where polarized lenses aren't recommended are airline pilots, snow skiers, and photographers—any instance where using LED crystal display gauges is very important.

It can also depend on individual experience: I wear polarized melanin lenses when golfing and love them, where occasionally other golfers have mentioned that polarized lenses make it tough for them to see the undulation in the greens and fairways. The key question is if the minor inconvenience of occasionally having some trouble reading gauges is worth the overall beneficial visual experience that polarized lenses offer, or if by wearing polarized lenses, the person's life and living will be severely compromised.

— Paul Zito, president,
Encore Optics, LLC,
South Windsor, Conn.

IT'S PHOTOCHROMIC

Q What's the most effective way to activate plastic photochromic lenses?

A Natural light is the best, most realistic activator. So, if possible, take a walk outside with the lenses and activate them in normal sunlight. That said, an in-office UV demonstration device is a convenient way to show patients in-office how photo-chromic lenses darken.

You can also wear photochromic lenses yourself and show patients how your personal lenses darken and lighten by either walking outside or using a demonstrator.

This is a high-impact way of demonstrating photochromics, since patients will be impressed that you've invested in the technology and can talk about it from firsthand experience.

— Gregory Rudin, president,
Expert Optics, Shorewood, Ill.

SHAVING FACE:  Another Answer

A Regarding the July Ask the Labs segment on shaving glasses, I believe the answer was based on a common misconception of physics and mirrors. Instead of giving the patient a pair of glasses focused from the mirror to the patient's face, it's important to note that the focal length of a mirror is actually twice that distance. The image is projected at a distance equal to that of the object in front of the mirror. In other words, the image is actually projected as far behind the mirror as the object is in front of the mirror.

The glasses in question would likely need to be half of the add power needed for the distance the mirror is from the patient's face, otherwise the focal point will be at the plane of the mirror and the image would be blurred.

— Stephen M. Montaquila, OD, Dr. David W. Ferris & Associates, Warwick, R.I.

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.