About safety glasses
Safety glasses refer to eyewear which protect the eyes from flying objects, dust, chemicals, heat, harmful light occurring during work.
Considering the JIS standards (Japanese Industrial Standards), wearing safety glasses is recommended for all workers as well as anyone entering the worksite.
▶Features
| • Impact resistance (durable lenses and frame) |
| • Wear resistance (Scratch resistance on lens surface) |
| ・Heat resistance( Hardly deformed by heat), etc. |
▶Applicable to
| • Workers and anyone entering worksites with a variety of jobs in which flying objects, dust, chemicals, and heat occur |
| • Workers and anyone entering worksites where the eye can be exposed to UV rays and other harmful light |
Types of glasses, styles, and codes
Lens quality and safety under JIS standards for protective eyewear
The JIS standard specifies the quality of lenses and strictly regulates safety to protect workers' eyes from flying objects, dust, chemicals, heat,and harmful light and to prevent vision loss and eye fatigue when workers wear protective eyewear.
Lens quality
● Parallelism
Parallelism refers to the angle (margin of error) at which light diverges when passing through the lenses of safety glasses. JIS dictates a parallelism of 0.16 cm/m, meaning that light one meter away passing through the lenses must have a margin of error within 0.16 cm.
● Spherical surface refraction
Spherical surface refraction is represented by the average value of the refractive power values of the lens's two primary meridians. JIS prescribe a value of or less than 0±0.12 m-1 in the visual axes and three points within 40 mm around the visual axes.
●Cylindrical surface refraction
Spherical surface refraction is represented by the absolute value resulting from the difference of the lens's two primary meridians. JIS prescribe a value of or less than 0.12 m-1 in the visual axes and three points within 40 mm around the visual axes.
●Transparency (rate of visible transmittance)
Transparency refers to the ratio of light passing through the lens which the eye senses. A rate of 0% refers to complete blackness without any light making it through the lens, whereas 100% is akin to complete visuality without a lens at all. JIS requires a ratio of 85%, with the lens being nearly transparent.
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0%
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85%
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100%
Lens safety
● Impact resistance
Impact resistance is tested by dropping a steel ball with a diameter of approximately 22 mm and a mass of approximately 44 g from a height of 1.27–1.30 m onto the glasses to make sure the lenses don't break, crack, or pop out of the frame.
● Heat resistance
Glasses must stand up to 30 minutes or more in an environment of 55±2°C and 23±3°C without deformation and parallelism, spherical surface refraction, and cylindrical surface refraction meeting the lens quality standards.
