ISO 10942-2022 pdf download – Ophthalmic instruments — Direct ophthalmoscopes.
5.3 Construction and function of the viewing system
5.3.1 The viewing lenses shall be arranged so that, as viewed from the observer’s side:
a) increments of positive power, indicated by black or green figures, increase when the disc is turned
clockwise;
b)increments of negative power，indicated by red figures,increase when the disc is turned
anticlockwise.
5.3.2The viewing lens control shall be provided with indexing stops for each lens power.5.3.3 Left-hand and right-hand operation of the viewing lens control shall be possible.5.4Construction and function of the illumination system
5.4.1 The defocused illumination beam shall be homogenous and achromatic as determined by visualinspection.
5.4.2The minimum adjustment range of the luminous flux from the illuminating system of Group Adirect ophthalmoscopes shall be from the maximum to 10 % of the maximum.
5.4.3 Group A direct ophthalmoscopes shall have a minimum oftwo aperture stops in theilluminatingsystem. These shall be a full aperture and a reduced aperture.Additionally a red-free filter shall beincluded.
NOTE other filters, apertures, ophtalmoscope graticules, slits or half-circles are optional.
5.5Optical radiation hazard with direct ophthalmoscopes
This clause replaces IEC 60601-1:2005+A1:2012,10.4,10.5, 10.6 and 10.7
The direct ophthalmoscope shall conform to the relevant requirements in accordance with ISO 15004-2.
6 Test methods
6.1General
All tests described in this document are type tests.
6.2Checking the optical and functional requirements
6.2.1 The requirements specified in 5.2 shall be verified by the use of measuring devices withaccuracy better than 10 % of the smallest value to be determined.
Measurements shall be carried out according to general rules of statistical evaluation.
For measuring the refractive power according to ‘Table 2, a focimeter as specified in IS0 8598-1 shouldbe used.
6.2.2 For measuring the field of view, place the direct ophthalmoscope so that the back surface of theinstrument is 12 mm in front of a pin-hole illuminated by a non-collimated light source.
6.2.3 The requirements described in 5.3 and 5.4.1 shall be checked by observation.
lt is essential that the divergent angle of the light source exceed the minimum angle of field of viewspecified in Table 1.
Project the light patch onto a screen at a distance l (expressed in millimetres) from the pin-hole (seeFigure 1). Measure the diameter d (expressed in millimetres) of the fully illuminated, central core of thepatch, disregarding the penumbra rim.
7 Accompanying documents
The direct ophthalmoscope shall be accompanied by documents containing instructions for use. Inparticular this information shall contain:
a) the name and address of the manufacturer;
b)any additional information as specified in IEC 60601-1:2005+A1:2012,7.9;
ca reference to this document (IS0 10942:2022), if the manufacturer or supplier claims compliance with it.
8Marking
The direct ophthalmoscope shall be permanently marked with at least the following information:a) the name or trade name and full address of the manufacturer;
b) where applicable, an authorized representative within the locale;
a distinctive identification i.e.commercial product name, model number or catalogue number;d)the classification according to Clause 4;
e)marking as required by IEC 60601-1.ISO 10942 pdf download.