Impact Resistant Materials

The two videos below show just how tough impact resistant lenses are compared with standard acrylic lenses. Impact resistant lenses look the same as standard optical lenses. However they are made from special polymers provide good clarity but are extremely flexible. This flexibility allows the lens to absorb the energy of a high velocity impact without shattering.

Of the many different optical lens material available only two have the necessary qualities to make prescription safety glasses. They are POLYCARBONATE and TRIVEX lenses.

Polycarbonate Lenses

Safety lenses made from polycarbonate material are extremely flexible and resistant to impact. In fact they are more than 40 times more impact resistant than standard plastic lenses. Polycarbonate is also lightweight and therefore comfortable to wear and blocks 100% of the sun’s harmful UV radiation. More than 90% of all safety glasses are made with Polycarbonate lenses.

Polycarbonate does have some disadvantages, mainly being it is sensitive to common solvents such as ACETONE and Alcohol. The slightest contact with these solvents can soften polycarbonate lenses rendering them unsafe. The optical clarity of Polycarbonate while satisfactory is not as good as the clarity of regular optical lenses.

Trivex- Solvent Resistant Lenses

TRIVEX also branded as TRILOGY or PHOENIX sets a new benchmark in eye protection as it resistant to most common industry solvents.

Polycarbonate vs Trivex Lenses

While both Polycarbonate and Trivex lenses offer adequate eye protection for medium impact in accordance with ASNZs/1337.6. Polycarbonate does have the distinct advantage of being able to withstand a much higher velocity impact than Trivex before breaking. It also costs a bit less and comes in a wider range of lens styles.

Trivex material however, is more optically stable giving the wearer greater optical clarity than Polycarbonate. Most importantly Trivex is relatively unaffected by contact with solvents and even resists highly corrosive liquids including ammonia and hydraulic fluids. If you think your employee?s safety glasses will come in contact with any solvents then Trivex lens material may be the best option. See Fig. 1 below

CR39 Non Safety Polycarb Trivex

Fig. 1. Effect of Solvents on Polycarbonate and Trivex Safety Lenses
The Three lenses to in Fig 1 have been exposed to a common solvent- Acetone. Trivex is unaffected while The polycarbonate lens is destroyed.

Optical Clarity Comparison

The view through two lenses on Fig 2 demonstrates how the higher chromatic dispersion of polycarbonate gives rise to image distortion. Trivex gives superior clarity of vision

Features and Benefits of Polycarbonate & Trivex

Please refer to following table as a guide to help you select the best lens material for your work activity.