SIST EN 167:2002

SIST EN 167:2002 is the Slovenian identical adoption of EN 167:2001 from SIST. It specifies optical test methods for personal eye-protectors, and the requirements being checked are defined in other EN standards.

This document is for manufacturers, test laboratories, and quality or compliance teams that need to measure optical performance of eye-protectors such as spectacles, goggles, and face-shields. It gives the methods used to verify refractive power, light diffusion, transmittance, and related optical properties.

What does SIST EN 167:2002 specify?

SIST EN 167:2002 specifies the optical test methods used for eye-protectors whose product requirements are given in other EN standards. It also points readers to EN 168 for non-optical test methods and to EN 165 for terms.

The document is organized as follows:

Alternative methods may be used if they are shown to be equivalent. In practice, that gives laboratories some flexibility, but the results still need to match the intent of the standard.

What are the key requirements of SIST EN 167:2002?

SIST EN 167:2002 focuses on a small set of optical checks that show whether an eye-protector will affect vision in use. The main requirement is not a single pass/fail number, but a set of defined measurement methods and reporting rules.

Refractive power testing

Clause 3 covers spherical, astigmatic, and prismatic refractive powers. For unmounted oculars and mounted products, the sample is tested in the as-worn position when that position is known; otherwise the geometric centre is used.

This matters because the optical result has to represent how the user actually sees through the product, not just how a flat sample behaves on the bench. If the telescope image shows doubling or another aberration, the ocular may be treated as defective or checked further using Annex A.

Light diffusion

Clause 4 gives two ways to measure reduced luminance factor: a basic method and a simplified method. The basic method is for oculars without corrective effect and for all shade numbers; the simplified method is for oculars with corrective effect.

The document also limits the relative measurement uncertainty for reduced luminance factor to 25%. In practice, the test method chosen has to match the product type, and the laboratory has to control uncertainty well enough to make the result meaningful.

Material and surface quality

Clause 5 uses visual inspection with a light box or illuminated grid. If the appearance is doubtful, the standard directs the user to objective checks using a 5 mm light beam and the methods for transmittance, diffusion, and refractive power.

This means appearance alone is not enough when quality is in question. The tester should confirm whether visible marks or defects affect optical performance.

Transmittance and transmittance variation

Clause 6 measures transmittance with radiation falling normally on the ocular and on the frame areas through which light can reach the eye. Clause 7 then checks how luminous transmittance varies across the lens area.

This is important for tinted lenses, gradients, and multi-zone products. The standard defines the test area around the centre, excludes a 5 mm marginal zone, and allows corrections when thickness variation is part of the design.

Infrared reflectance

Clause 8 measures spectral reflectance in the infrared over 780 nm to 2 000 nm at a nominal 8° angle of incidence. This is the check used when infrared performance is relevant to the eye-protector design.

Localized refractive power

Annex A gives a small-area method for spherical and astigmatic refractive power. It scans a 5 mm beam across the sample and is intended for assessing local optical effects that the telescope method averages out.

What terms does SIST EN 167:2002 define?

SIST EN 167:2002 uses several optical terms that are central to the test methods.

• Visual centre - the point on the ocular used as the reference position for measurement when the wearer’s line of sight is being represented.
• Geometric centre - the physical centre of the ocular, used when the visual centre is not known.
• Prismatic refractive power - the prism effect of the ocular, expressed in cm/m, which shifts the image position.
• Spherical refractive power - the overall lens power measured in the telescope method.
• Astigmatic refractive power - the difference in power between two principal meridians.
• Luminous transmittance - the amount of visible light that passes through the ocular.
• Reduced luminance factor - the diffusion measure corrected for transmittance so products can be compared more fairly.

Who uses SIST EN 167:2002?

SIST EN 167:2002 is used by eye-protector manufacturers, optical test laboratories, and quality assurance teams. It is also useful for purchasers and certification staff who need to verify that a product’s optical performance is checked by the same method each time.

It is especially relevant for products such as spectacles, goggles, and face-shields. These users rely on the standard when selecting test equipment, setting up measurements, and reporting results.

What changed in SIST EN 167:2002 from the previous edition?

SIST EN 167:2002 replaces EN 167:1995.

Which standards are used with SIST EN 167:2002?

SIST EN 167:2002 relies on three companion standards:

• EN 165 - provides the vocabulary used for terms such as visual centre.
• EN 166 - gives the specifications for personal eye-protection that the tests are meant to support.
• EN 168 - gives the non-optical test methods that complement this standard.

What does the SIST EN 167:2002 document contain?

SIST EN 167:2002 contains detailed test set-ups, apparatus descriptions, and measurement procedures. It includes figures for the telescope target, prism test arrangement, diffusion test arrangements, and the small-area refractive power method in Annex A.

It also includes calculation methods and formulas for transmittance, reduced luminance factor, thickness correction, and infrared reflectance. Annex B explains how to treat uncertainty of measurement in reporting, and Annex ZA links the clauses to EU Directive essential requirements.