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Keeping an eye on safety

When it comes to lens coating technology Sperian leads the way

By Philip Johnson

Protective eyewear is a crucial part of any safety program and there are many different kinds of eyewear on the market from which to choose.

Their design, features, functionality and even the materials from which they are made all affect their performance.

Lens coatings are one of those features that have a major impact on the effectiveness of protective eyewear.

Choosing the right lens coatings not only help keep employees safe and comfortable in the workplace, but can also translate into fewer injuries, increased productivity and an overall healthier bottom line.

Advances in plastic lens technology, particularly the development of polycarbonate material, have created incredibly strong, flexible and lightweight lenses. Polycarbonate lenses, because of their higher refractive index (they bend light more than glass), are thinner and lighter than both standard plastic and glass. They also have higher impact resistance than glass, which shatters under force, making polycarbonate lenses the lens of choice for protective eyewear.

Polycarbonate lenses, however, do not inherently feature scratch resistance, glare reduction, antifog capabilities or laser protection — they require coatings to provide clear vision and performance for different work environments.

Various coatings can be applied to improve scratch, impact and chemical resistance, protect against ultraviolet (UV) and infrared (heat) radiation, and provide anti-fog properties for work environments where excess moisture is present. When combined with coatings and tinting, polycarbonate lenses can provide a complete eyewear protection package.

Polycarbonate lenses provide lightweight, comfortable eye protection that lasts, improving user compliance and safety.

Increasing compliance for eye protection is one of the most effective means to increase worker safety and productivity.

Non-compliance with AS/NZS standards can result in lost production and worker injury.

According to the Optometrists Association Australia, 60 per cent of all eye injuries happen in the workplace and about 95 per cent of eye injuries are the result of carelessness and lack of attention.

Grinding and welding are the two most common tasks being performed when an eye
injury occurs.

Lens coatings improve compliance because workers tend to keep their eye protection on when they are able to see their work clearly.

Lens coatings enhance clear vision through improved scratch resistance, wavelength
filtering and anti-fog properties. With improved fabrication techniques and manufacturing methods, companies now produce lens coatings for almost any application.

From common hardcoats to mirror coatings designed for outdoor use, manufacturers offer product lines with an array of options and benefits.

Advances in lens coatings include new and improved anti-fog formulations, added UV
protection and protection from chemical splash.

In addition, there are specialized coatings designed to protect the eyes from laser radiation.

No lens material, including glass, is entirely scratch proof, making it important to treat lenses with a clear, durable coating. Scratch-resistant hardcoats — perhaps the largest category of lens coatings — provide longer life for the lens and preserve visual clarity.

For best results, protective eyewear should be cleaned and cared for according to the
manufacturer’s instructions.

Manufacturers like Sperian, continue to improve and perfect scratch-resistant coatings to increase lens clarity, by producing coatings such as Supra-Dura that has five times more scratch resistance than most hard coats on the market.

The lenses are treated with a hardcoat that withstands rigorous testing and performs extremely well in the most demanding work environments.

Because the lenses resist scratching better, they last longer and require less frequent replacement, a cost-saving benefit to safety managers. And because they provide ongoing optical clarity, workers are more likely to wear them, resulting in a workforce that is better protected than one that removes safety eyewear due to poor visibility caused by lens scratches.

While polycarbonate lenses offer inherent UV protection (over 99 per cent), mirror coatings are often used to enhance that protection and comfort the eye when exposed to heat (infrared radiation) in hot environments.

Mirrored lenses are frequently used in conjunction with a tinted lens and are ideal for general purpose sun and glare protection in work environments such as landscaping, construction, ground and air transportation, and utilities. A light application of a mirrored coating to a clear lens works well for work conditions that require frequent transition between indoor and outdoor activities, such as operating a forklift at a receiving dock.

Certain environments and some types of eye protection, such as high coverage spectacles and goggles, are particularly susceptible to fogging due to the lack of airflow around the lenses. When a lens fogs it temporarily interrupts the wearer’s field of vision, which can lead to a potentially dangerous situation.

To help minimise fogging, manufacturers apply anti-fog coatings to improve the performance of the eyewear.

Currently, there are two distinct anti-fog lens coatings that work for different moisture levels.

Hydrophilic or “water loving” coatings absorb water into the coating matrix and evaporate moisture. They are most effective in moderate moisture situations, including many factory settings (food processing plants, for example), or when an individual’s body heat is warmer than outside temperatures due to physical exertion.

Hydrophobic or “water spreading” coatings create a sheeting action where the water forms a uniform film on the surface of the lens, without impairing the user’s vision.

Hydrophobic coatings are useful in environments that are very steamy, where exertion levels are high, or where people transition between work in very low temperatures (freezers) and higher temperatures (outside in humid climates).

However, many hydrophobic anti-fog coatings are not permanent and easily erode after repeated cleanings.

One innovation that has created a stir in the market is technology that creates an anti-fog lens for all seasons and all environments.

Leading manufacturers, like Sperian, have implemented this technology and now offer protective eyewear that features both hydrophilic and hydrophobic properties.

This improved user compliance delivers better safety results, and helps ensure that AS/ NZS requirements are met.

Selecting eyewear and coatings that offer the best functionality, style and comfort can help increase user compliance. The results are a safer workplace, fewer incidents of eye injury, and ultimately increased productivity and profitability.

*Philip Johnson is Director of Technology, Sperian Eye & Face Protection, Inc.

Sperian Protection
Ph: 1300 139 166
www.sperian.com