Eyes are the most important sensory organs of the human body. Around 85-90% of all our sensory impressions are conveyed by sight, so it is all the more important to protect these sensitive organs from injury.
Many jobs, however, expose workers to situations that may be hazardous to their eyes. In the workplace, natural defences such as eyelids, blinking reflexes, tears and eyelashes are hardly ever sufficient to afford secure protection and consequently, workers need protective eyewear. The personal protective equipment (PPE) to be deployed should be selected according to the following criteria:
• Compliance with standards (certification and labelling)
• Adequacy of the protective function
• Suitability for the conditions in the workplace
• Suitability in respect of health and ergonomic requirements
Common causes of eye injury include mechanical hazards, such as flying metal or glass splinters, tiny particles, machinery, liquid splashes, chemical hazards or harmful optical radiation.
Typical working areas where protective eyewear is needed include milling,?turning and planing, precision mechanical work, assembly and laboratory work, or working in dusty environments. Protective eyewear must also be used by visitors to these areas. Protective goggles fitted with different lens shades are used to afford protection for welding, metalworking, working near furnaces and for the outdoors (to eliminate glare in bright sunlight). These varied fields of application illustrate there are different types of protective eyewear to suit every requirement.
While the most frequently used eyewear is of the side arm variety, wide vision goggles are generally held in place by an adjustable headband. The wide range of protective eyewear includes welding goggles, laser-protection goggles and prescription lens safety eyewear.
All protective eyewear has to comply with the special European Standard provisions, namely DIN EN 166-172, and needs to be certified by an independent testing institute. The equivalent for the US market is the ANSI Z 87.1 Standard.
Materials for safety eyewear
Where materials are concerned, most protective eyewear has plastic frames made of polycarbonate, polyamide or thermoplastic elastomers. The advantage offered by these materials lies in their high level of resistance to the various conditions prevailing in the workplace. There are also safety spectacles with metal frames, but these are now mainly used for classic twin-lens spectacles. These spectacles have a distinct disadvantage in that the design of the frame obstructs the field of vision to a greater degree than is the case with single lens spectacles.
Lenses and coatings
Most safety eyewear lenses are made of polycarbonate, a popular material most often used to make CDs. It offers the advantage that as well as being flexible and light, it is also extremely stable. The high impact resistant polycarbonate lenses consequently meet the most demanding requirements for mechanical stability and the highest optical quality class.
Conversely, safety eyewear made of mineral glass, glass compound or toughened glass does not offer particularly good wearer comfort, because it is relatively heavy, and its mechanical resistance is not very high.
The use of different lens coatings means that protective eyewear can be made suitable for virtually any working condition, and the most wide-ranging spectrum of applications. In particular, scratch resistant coatings are widely used.
Lenses are often damaged during everyday use through scratching, abrasion, wiping and rubbing against different materials. This means that a scratch resistant coating can significantly lengthen the service life of the safety eyewear.
Anti-fog coatings further add to protection in the workplace as they prevent any misting up which might obscure vision, especially where there is a high level of humidity or working areas are subject to sudden fogging.
There is an essential distinction between the immersion and flood coating application processes. With flooding, optical surfaces of the lens are alternately flooded with the coating. This process enables different coatings to be applied to the inside and the outside of the lens.
Manufacturers specialising in this coating technology offer protective eyewear that is scratch resistant on the outside and permanently fog-free on the inside.
Develpoments in coatings
The latest developments are active photochromatic coatings. First class photochromatic lenses darken in direct sunlight (e.g. in the presence of UV rays) within 10 seconds, and in this way deliver ideal protection from the sun’s harmful rays. In the absence of UV radiation, the lens will again lighten within around 30 seconds. Safety eyewear with these coatings is particularly suited to workplaces that are subjected to frequent changes in light?conditions, such as from indoors to outdoors, or from light to dark. This obviates the need for two pairs of spectacles, which up until now has been the case.
When selecting protective eyewear, wearer acceptance is a critical factor. A feeling of personal safety and a positive experience with the product will make employees use protective eyewear as a matter of course. This leads to better safety in the workplace. Many manufacturers have recognised that for good user acceptance, the products they develop have to meet not only the demands of maximum protection, but also have to be well designed and offer good wearer comfort.
The subject of spectacle weight is an increasingly major consideration. Since lightweight safety spectacles are hardly noticed by the wearer, this is a guarantee of trouble-free usage. Adjustable side arms, easy lens changes and anatomically designed soft ear-pieces are further features which significantly enhance the wearer comfort of safety eyewear.
Extremely comfortable soft/hard combinations of materials for frames and side arms are manufactured using a creative injection moulding process using new innovative technologies and materials. In these spectacles, the central part holds the lens to ensure maximum protection, while the soft, flexible components adapt perfectly to the individual facial features and avoid pressure on the forehead, nose or cheeks. Soft ear-pieces further ensure a comfortable fit.
Another feature that adds to wearer comfort is the adjustable angle of inclination. The sidearm length and angle of inclination on safety spectacles can be precisely adjusted to give an ideal personalised fit.
At a time when design and a sporty styling are important in the world of the worker, personal safety equipment is increasingly selected on the basis of its contemporary appearance. The influence of fashion should not be underestimated by manufacturers and buyers, since even the best protective eyewear can only work if it is worn, and worn at all times.
Gerhard Dietl, Product Manager of Protective Eyewear at uvex Arbeitsschutz GmbH
• Training: Industrial optics/optician
• Product Manager for protective eyewear and hearing protection in the industrial health and safety sector for nine years
• Seminar lecturer on eye protection for internal and external training at the uvex academy
• Many years of experience in the optical sector in ophthalmic optics and lens manufacturing
• Additional experience in sales and marketing
Published: 01st Aug 2010 in Health and Safety Middle East