eye on equipment

What Smell?

Susan Tarrant

Q Why do high-index lenses produce an unpleasant odor during edging? Is it harmful? And what can I do to keep the odor from drifting through to the rest of the practice?

A All 1.67 and 1.60 lenses are made with a resin that provides a stronger, safer, lighter, and more optically superior lens product. According to the Material Safety Data Sheet (MSDS), hydrogen sulfide is the only classified chemical class with an established threshold limit value (TLV) set by the American Conference of Governmental Industrial Hygienists.

The actual TLV at time-weighted average (TWA) is 10 parts per million (PPM), which is the level at which workers can work a 40-hour week repeatedly exposed to the product without any adverse health effect. The actual measured results at 5cm to 10cm around the edging point are 0.01 PPM or less. That is to say, the exposure is 1,000 times less than the TLV-TWA, and safety is not a concern.

The best way to eliminate odor associated with edging high-index lenses is to use a deodorizing unit. These are separate units attached to your edger (dry or wet) that filter the fumes through a filter (see sidebar to the right).

If you don’t use a deodorizing unit, there are a few other methods you can employ to help manage the odor. None are as effective, but they will help reduce issues with odor.

■ Ventilation. Install a ventilation hood or hose over the edging area to draw odors out of the area and vent them outside.

■ Circulate. Use a ceiling fan or floor fan to move the air around.

■ Creative work hours. Save your high-index jobs for after or before office hours, when patients and customers, as well as other employees, will not be bothered.

■ Go wet. Use a wet edger, if possible; it’s going to eliminate some of the odor. And, be sure to change the water frequently to reduce odor.

■ Dust masks. This isn’t going to reduce the smell for anyone else in your lab or practice, but wearing a dust mask will help those operators who are particularly sensitive to the smell.

■ Air deodorizers. We’re not talking Glade air spray (though that would create an interesting smell). We’re talking about the kind that recirculates the air through a charcoal filter. EB

Many thanks to the finishing equipment experts who provided these tips: Andy Huthoefer, vice president, product development, Satisloh North America group; Matt Menzies, technical manager, Briot/Visionix; Franco Aluigi, product manager, Santinelli International; and Matt Vulich, vice president, marketing, AIT Industries.