ISO 15253:2021 Ophthalmic optics and instruments — Optical and electro- optical devices for enhancing low vision.
5.1.4 Flammability/Ignitabillty
When the device is tested as described in IEC 60695-2-11, there shall be no continued combustion after withdrawal of the test rod.
5.1.5 Resistance to perspiration
Parts of the device that are normally in contact with skin, as on the face and head, and that are covered
by the scope of ISO 12870 shall meet the relevant requirements of ISO 12870.
5.1.6 Robustness
Spectacle magnifiers and spectacle- and head-mounted magnifiers shall meet the relevant requirements of ISO 12870 and ISO 14889.
Tinted lenses and filters shall meet the relevant requirements of ISO 12312-1.
If appropriate, electro-optical devices shall meet the relevant requirements of IEC 60601-1-3.
5.1.7 Resistance to drop
If claims are made that the device is drop-resistant. the manufacturer shall state the conditions under which this claim is made and the conditions of testing.
5.2 Optical devices
5.2.1 Spatial resolution
The resolution of the optical device shall he measured at an object contrast of not less than 80%. Devices designed for near/intermediate use
When tested in accordance with 6.2,1. the device shall resolve a target that consists of line pairs measuring not more than 0,233 mm per pair (0,116mm per element) within the central 70% of the linear field of view, for targets having white light meeting the specifications of CIE standard illuminant D65 within the illuminance range of 750 lx to 1 000 lx with the device used as intended by the manufacturer.
NOTE 1 0,116mm is the element size that subtends l’of arc at a distance of 400 mm.
NOTE 2 For stand magnifiers it is recommended that the manufacturer state the range of viewing distances for which the magnifier meets the resolution requirement and also state the range of resolvable fields of view for this range of viewing distances. Devices designed for distance vision
When tested in accordance with 2.1, the device shall resolve targets consisting of line pairs subtending an angle of 2’ (or less) having elements subtending an angle of 1’ (or less) within the central 70 % of the linear field of view, or the central 10°, whichever is the smaller. If these requirements exceed the diffraction limit of the device, then the smallest resolvable element spacing, specified in cycles per degree, shall not be less than 50% of the diffraction limit for monochromatic light at 555 nm within the above specified area. The telescope shall meet these requirements at the limits of the claimed working range.
5.2.2 Equivalent power (applies to optical devices designed for near or Intermediate use)
The equivalent power of a spherically powered magnifier or fixed-focus telemicroscope/near-vision telescope measured along the optical axis shall he stated by the manufacturer and shall be within ±5 % of the value stated.ISO 15253 pdf download.