HANDS ON - Ask The Labs
by Karlen McLean, ABOC, NCLC

DEEP BLUE SEE

Q Is it true that gray polarized lenses are recommended for deep water fishing and brown polarized lenses are recommended for shallow water fishing?

A While there are limited scientific data addressing this question, we've accumulated a great deal of information over the years from experienced fishermen.

The preferred polarized lens color for deep water fishing is brown. It is effective in reducing glare in bright sun and also heightens vision in low light conditions.

When fishing in shallow water, such as a trout stream, amber polarized lenses are ideal. Polarization eliminates most of the top water sheen, and because amber tends to be somewhat lighter in color, image flattening is avoided. This allows contrast between the fish and the background or bottom structure.

—Charles E. Van Tassel, president, Beloptix, Inc., Old Lyme, Conn.

ACETONE TIPS

Q Can acetone be used safely on Trivex lenses? What about on polycarbonate?

A Acetone, and even less volatile solvents such as rubbing alcohol, are immediately absorbed by exposed polycarbonate and may cause the material to become opaque and lose impact resistance.

Some tips if you must use solvents on polycarbonate:

1. Avoid using solvents on your patient's old lenses. Solvents can be absorbed through hairline scratches.

2. Avoid contact with the edges of cut lenses and in drilled lens holes. Use a cotton swab to limit concentration of solvent on the lens surface.

3. Avoid allowing the solvent to come in contact with screw-locking adhesives as it can cause stress cracks on the lens edge.

An important note: Stress cracks may form in time when using lens cleaners containing alcohol. The presence of alcohol can be noticed by its odor or by checking the label.

Trivex was designed to have impact resistance similar to poly and to resist chemicals. It is unaffected by acetone or rubbing alcohol.

—Renato Cappuccitti,
director retail and national sales, HOYA Vision Care North America

Picture This

Q We have a professional photographer as a customer who currently wears a standard plastic single vision -2.50 with -0.50 cylinder OU Rx. He always scratches his lenses on the camera while taking photos. What can you suggest to help this problem?

A First, ask your patient to make sure that there is a rubber eyepiece on all of the cameras he uses. Most cameras have rubber eyepieces as standard equipment, but in some cases this could be missing. Next, we'd recommend glass lenses. Although glass is heavier in weight than plastic products, glass doesn't scratch as easily as plastic. Glass also features excellent visual acuity, which a photo-grapher can appreciate. Perhaps a glass lens in a small frame just for "photo time" is the answer.

—Corrine Hood, president, Katz & Klein, Inc., Sacramento, Calif.

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.