ISO 15253 pdf download – Ophthalmic optics and instruments -optical devices for enhancing low vision

ISO 15253 pdf download – Ophthalmic optics and instruments -optical devices for enhancing low vision.
5.2 Materials and construction
5.2.1 Materials
Components designed to come into direct contact with the skin of the patient shall be made from a material which,
when used as Intended by the manufacturer, shall conform with ISO 15004.
5.2.2 FlammabIlity
When the device is tested as described In ISO 15004. there shall be no continued combustion after withdrawal of the test rod,
5.2.3 Resistance to immersion
For devices that are claimed to withstand immersion in water, the following requirement shall be met:
After the device has been fully immersed for 5,0 mm ± 0.5 mwi in water at 40 °C to 45°C and allowed to dry in air at
20°C ± 5 °C, it shall comply with all requirements specified in this Internalional Standard.
5.2.4 ResIstance to perspiration
Parts of the device covered by the scope of ISO 12870 (spectacle frames) shall meet the relevant requirements of ISO 12870.
5.2.5 Robustness of head-mounted, including spectacles and spectacleeounted, devices Parts of the devce covered by the scopes of ISO 12870 (spectacle frames) and of ISO 14889 (spectacle lenses)
shall meet the relevant requirements of ISO 12870 and ISO 14889.
5.2.6 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.
6 Environmental conditions of use
tinder the envwonmental conditions of use given in Table 3. aM requirements specified in this International Standard shall be met. These requirements take precedence over 5.1 of ISO 15004:1997.
Al Principle
A series of distorlion assessment charts representing barrel distortion at a number of discrete levels are presented in a range of sizes. The grids of the appropriate size are viewed with the magnifier or telescope under defined conditions and the degree of prncushion distortion is estimated from the grid or grids which most nearly compensates for me magnifier’s distortion.
NOTE The maorlly of devices only edibit pincushion distortion; this test deals with that form of catocbon only.
A.2 Apparatus
A.2.1 Hand and stand magnifiers
L21.1 Distortion assessment charts. generated by means of a computer program to represent, respectively, barrel distortions of 0%. 5%, 10%, 15% and 20% for hand and stand magnifiers. The charts are presented in six rows In descending order of size.
See Figure Al.
4.2.1.2 Adiustable brow support In the form of a stand with a crossbar, in order to standardize me position from which the distortion of the magnifier is assessed.
A.2.2 Distance and atocal telescopes
A.22.1 Distortion assessment charts. generated by means of a computer program to represent, respectively, barrel distortions of 0%, 2,5%, 5%, 7.5% and 10% for, principaly, distance telescopes. The charts are presented as 4 x larger versions of those generated for magnitiers Some near-vision telescopes are found to work better with the magnifier assessment charts, due to their shorter working distances.
A.3 Procedure
A.3.1 Magnifier viewing position
For magnifiers where the object distance is governed by a fixed frame or stand, place the chart flat on a table and mount the magiifier on me chart with the centre spot of a suitable grid on the optical axis of the magnifier. Hand magnifiers shall be attached to an adjustable stand and the distance between the test chart and the magnifier shall be set in accordance with the manufacturers instructions for use Move the stand so mat the centre spot of a suitable grid is on the optical axis of the magnifier.
Use the brow support to fix the distance at which the assessment will be done. The distance between the magnifier and the assessors eye shall be set In accordance with the manufacturer’s instructions for use. The assessors eye shall lie on the optical axis of the magnifier.