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176 Ophthalmic Lenses

When you look for safety glasses, there are a number of things to be
considered:
• Ensure that the safety eyewear meets the standards applicable for your
region and also usage. In USA “ANSI Z 87” should be marked on the
frame and the manufacturer’s initials and any special lens attribute
should be noted on the lens.
• Look for the safety glasses made with high quality, virgin resin
polycarbonate material. Recycled resins are cheaper, but they are also
burdened with a high degree of distortion and yellowing lenses are not
as durable.
• Zero distortion lenses allow you to not only see more clearly through
the safety glasses, but also allow you to wear them for longer periods of
time without eyestrain or fatigue.
• If you wear the safety glasses over top of your prescription lenses or
reading glasses, make sure that they are large enough to fit. Safety glasses
with bifocal lenses are available, sometimes allowing you to take off
your prescription glasses altogether.
• Fit is very important. There are a few aspects to this – width of the
frame, width of the nosepiece, length of the temples and angle of the
temple with respect to the lenses.
• Fit ensures comfort, but additional features can enhance this. If the
nosepiece is soft, rather than a molded in part of the lens, it will enhance
comfort. If the glasses have soft pieces on the temple tips, they will be
easier on your ears. If the temple frame is thinner and more flexible,
that also adds to comfort. Lastly, if the glasses are lighter in weight,
that will help ensure a comfortable wear.
• Replacement lenses, if they are available, can help reduce ongoing costs.
However, for most styles of safety glasses, the most expensive
component is the lens, so don’t expect to be paying a lot less for just the
lens.
• Degree of protection is more important than just the safety rating. So
the glasses can have the added features of side shields, wrap-around
lenses and brow guards.
• Lastly make sure the lens tint is applicable for your specific application.

LENS MATERIALS
The lenses for safety eyewear may be made of:
• Glasses
• Plastics
• Wire gauze.