It is important to know the characteristics and function of the eyes to understand which agents can damage then and which type of safety devices must be utilised to protect them.
Eyes act as a sensor for the human body, allowing it to perceive visible light. Light enters by means of a crystalline to be projected onto the retina, the inner part and the rear of the ocular bulb. From here, optic nerves take the image and sends it to the brain which decodifies it in a visual image. The entire ocular bulb forms the most tender part of the human body and for the 5/6 posteriors it is not visible, well-protected by bone, muscles, etc.
The sixth anterior is covered by the cornea and is the most exterior part and least protected of our eyes. This means that it is essential to protect the sixth part of the eye, in as much as, other than being exposed to hazards of individual vision, it is also the only system that leads directly to the brain. This fragile structure allows us to see and is fundamentally threatened by three categories of hazards:
TYPE OF HAZARD:
- mechanical: collisions of solid parts, dusts
- chemical: chemical substances
- luminous radiation: UV, infrared, visible, laser
On the basis of results reported from hazard evaluations, the employer must supply eye protection which responds to CEE safety pre-requisites, defined by European norm UNI EN 166:2004 which defines, as art. 4.1., that the eye protection must provide for protection against:
- different entity impacts
- optical radiation
- fused metal or incandescent particles
- sprays and drops
- electrical arcs
Art. 4.2. also defines the types of eye protection:
- glasses with side pieces which are with or without side guards
- mask glasses
- welding helmets
The eye protector must be marked both on the lens and on the frame. Mask glasses marking is set on the frame. Visors must have a support structure.
Marking must be made up of 7 fields:
1°) the first number indicates the type of luminous protection (example: 2=UV filter, 3= UV filter without colour alteration, 5=solar filter, 6=solar and infrared filter). The second number, set apart by a dash, corresponds to the gradation (a single number: gradation of a protector for welding).
2°) manufacturer brand
3°) optical class: indicates the degree of ocular optic neutrality
4°) mechanical resistance: S=increased robustness, F=low energy 162 km/h impact protection, B=medium energy 432 km/h impact protection (mask glasses and visor), A=high energy 684 km/h impact protection (only visors).
5°) field of use: 3=liquids, 4=coarse particles, 5=gas, 8=electrical arcs, 9=fused metals
6°) letter K if the eye protector is abrasion resistant
7°) letter N if the eye protector is anti-fog
It is important to verify the environmental characteristics of the workplace and the individual working activity to identify an eye protector with a good comfort index.