Ask the Labs
By Joseph L. Bruneni and Martine Breheny

FITTING HEIGHTS
Q What progressives are you familiar with that have a fitting height of 16mm or less?

--Shannon Ross, Precision Optical Group, Creston, Iowa

A Your question involves a sensitive subject. To answer it, we contacted manufacturers and asked what lenses they produce with a minimum fitting height of 16mm or less. The following includes lenses with a published minimum fitting height of 16mm or less: Hoya Lens' Summit CD and Summit 13; Seiko's Super Proceed; Rodenstock's Progressive XS; Zeiss' Gradal Short i; Shamir Insight's Piccolo; INDO's Micra; Polycore's Micro; and Pentax's AF.

Many other progressive producers said that some of their PALs could be fit at 16mm, but it was not officially recommended as the "minimum fitting height." The best way to ensure a successful fit is to follow each manufacturer's minimum fitting height.

SURFACING SENSE
Q  We are considering adding a surface room. We currently do about 25 to 30 jobs a day, which includes about six stock single-vision orders. We currently do about 30 percent AR, and it's growing. At what point does the investment become
practical? Another consideration is free-form generating. How much will that impact future on-site labs?

Jeff Sears, Tri-State Vision, Akron, Ohio

A One current factor not in your favor involves lens inventory.

The increasing number of substrates, lens designs, and photochromics require a larger (and more expensive) lens inventory for surfacing, particularly if the goal is faster service. You'll need added space and will have additional plumbing and electrical demands.

In terms of work flow, much depends on the product mix going through your lab. In-house lens casting makes some sense today. Previously, only casting of progressives provided much savings but photochromics and aspherics can also now be cast.

The new free-form equipment is an exciting development for mid- to high-volume surfacing labs, but doesn't offer much help for your lab at this point.

In-house AR won't make much sense until your AR usage increases. Equipment manufacturers can provide guidelines for determining when surfacing makes economic sense.

An Echofrom the Past
Q We are considering a new, high-end sunglass line featuring polarized glass lenses. We are trying to determine what the safety and legal ramifications are for offering glass sunwear. Are we within our legal limits and obligations of offering this type of sunwear to our patients? Also, should we be concerned about delamination?

A This recent development in polarized sunwear seems to defy current attitudes, but the manufacturer makes some interesting points about its new sunglass. The producer reports the following: "Our glass wafers are tempered so an impact would more likely chip or simply crack the lens rather than break it. Glass properties offer the scratch resistance with superior optics and durability. Glass works well for those less gentle with their eyewear. Many sunwear patients use polarized sunwear primarily for driving and glass holds up under vigorous wear and tear. Delamination issues have been eliminated and should not be a concern. For sports applications, polarized lenses are available in polycarbonate and should also be offered."

A reminder: Duty to Warn is a professional responsibility, so polycarbonate (or Trivex) should be discussed with every patient.

If you have a question you'd like to have answered in Ask the Labs, send it to Joseph L. Bruneni. Fax: 310-533-8165. Phone: 310-533-4975. E-mail: joe@bruneni.com. Or mail questions to: Vision Consultants, 2908 Oregon Court, #I-2, Torrance, CA 90503. An archive of past Ask the Labs columns can be found on the Eyecare Business Website at www.eyecarebusiness.com.