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1、STD-IS0 8598-ENGL L99b Li851903 07q2bbl TBO INTERNATIONAL STANDARD IS0 8598:1996 TECHNICAL CORRIGENDUM 1 Published 1998-05-01 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MErrmYHAPOIIHAR OPTAHH3AUHR Il0 CTAHMPTM3AUHH ORGANISATION INTERNATIONALE DE NORMALISATION Optics and optical instruments - Foc
2、imeters TECHNICAL CORRIGENDUM 1 Optique et instruments doptique - Frontofocomtres RECTIFICATIF TECHNIQUE 1 Technical Corrigendum 1 to International Standard IS0 8598:1996 was prepared by Technical Committee ISO/TC 172, Optics and optical instruments, Subcommittee SC 7, Ophthalmic optics and instrume
3、nts. This material is reproduced from IS0 documents under International Organization for Standardization (ISO) Copyright License number IHSllCC11996. Not for resale. No part of these IS0 documents may be reproduced in any form, electronic retrieval system or otherwise, except as allowed in the copyr
4、ight law of the country of use, or with the prior written consent of IS0 (Case postale 56,1211 Geneva 20, Switzerland, Fax +41 22 734 10 79), IHS or the IS0 Licensors members. Page 2 Subclause 4.4 Replace the second sentence with the following text: Translational movements of the lenses on the lens
5、support of not less than 30 mm in a direction perpendicular to the optical axis and to the adjusting rail shall be possible, starting from not more than 1 O mm below the optical axis of the instrument (see figure 1). “ l in which the phrase . starting from more than 10 mm below . “ has been correcte
6、d to “ . starting from not more than 10 mm below . n. ICs 11.040.70 Ref. No. IS0 8598:1996/Cor.l:1998(E) Descriptors: optics, opticai equipment, optical measuring instruments, frontofocometers, specifications, manufacturing requirements, accuracy, tests. (B IS01998 Printed i n Switzerland Copyright
7、International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:30:41 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8598 9b m 4851903 0669386 996 W INTERNATIONAL STANDAR
8、D IS0 First edition 1996-08-01 Optics and optical instruments - Focimeters Optique et instruments doptique - frontofocomtres Reference number IS0 8598:1996(E) Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/997254500
9、1 Not for Resale, 04/25/2007 01:30:41 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8598:1996(E) IS0 8598 9b W 4851903 0669387 822 Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodi
10、es). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be rep- resented on that committee. International organizations, governmental an
11、d non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bo
12、dies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 8598 was prepared by Technical Committee ISO/TC 172, Optics and optical instruments, Subcommittee SC 7, Oph- thalmic, endoscopic, metrological
13、instruments and test methods. O IS0 1996 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. Internati
14、onal Organization for Standardization Case postale 56 CH-121 1 Genve 20 Switzerland Printed in Switzerland II Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:30:41 MDTNo repro
15、duction or networking permitted without license from IHS -,-,- IS8 8598 96 m 4853903 0669388 7 b m INTERNATIONAL STANDARD Q IS0 IS0 8598:1996(E) Optics and optical instruments - Focimeters 1 Scope This International Standard specifies requirements for continuously indicating focimeters and digitally
16、 rounding focimeters with which the vertex powers and prismatic powers of spherical and astigmatic lenses, including lenses mounted in frames and contact lenses, can be measured and with which lenses can be orientated and marked. NOTE 1 For the measurement of vertex powers of contact lenses, see IS0
17、 9337:-11, Optics and optical instruments - Contact lenses - Determination of back vertex power. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions ind
18、icated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid I
19、nternational Standards. IS0 7944:-2), Optics and optical instruments - Reference wavelengths. IS0 8429:1986, Optics and optical instruments - Ophthalmology - Graduated dial scale. IS0 9342:-1), Optics and optical instruments - Test lenses for the calibration of focimeters. 3 Definitions For the purp
20、oses of this International Standard, the following definitions apply. 3.1 focimeter: Instrument that is used to measure vertex powers and prismatic effects of spectacle and contact lenses, to orientate and mark uncut lenses, and to verify the correct mounting of lenses in spec- tacles frames. 3.2 co
21、ntinuously indicating focimeter: Focimeter with a continuous scale. 3.3 digitally rounding focimeter: Focimeter which displays measured values rounded to the nearest incremental value. 3.4 lens support: Aperture on the instrument against which the lens or the contact lens is placed for measurement.
22、NOTE 2 The focimeter measures the vertex power rela- tive to the surface placed against the lens support. 3.5 adjusting rail: Movable rail or bar used as the reference axis for spectacles during measurement, which is aligned perpendicularly to the optical axis of the focimeter and parallel to the ax
23、is direction O“ to 180“. NOTE 3 Also called the lens table or frame rest. 3.6 principal meridians: The two meridians of an astigmatic power lens (see 3.1 O) containing the optical axis; one of the meridians has maximum refractive 1) To be published. 2) To be published. (Revision of IS0 7944:1984) 1
24、Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:30:41 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8598 96 = 4853903 Ob69389 bT5 I I VI 7 IS0
25、8598:1996(E) / m AI power, the other meridian has minimum refractive power. NOTE 4 In general, the two principal meridians are mutu- ally perpendicular to each other (regular astigmatism). O i *I 3.7 vertex power: There are two vertex powers of a lens. 3.7.1 back vertex power: Reciprocal of the para
26、xial value of the back vertex focal length measured in metres. 3.7.2 front vertex power: Reciprocal of the paraxial value of the front vertex focal length measured in metres. NOTES 5 Conventionally the back vertex power is specified as the “power“ of a spectacle lens, although the front vertex power
27、 is required for certain purposes, for example in the measurement of some multifocal lenses. 6 The unit for expressing vertex power is the reciprocal metre (m-1). The name for this unit is the “dioptre“ for which the symbol is “D“. 3.8 prismatic power: Deviation of a ray of light through a specified
28、 point on a lens. NOTE 7 The unit for expressing prismatic power is the centimetre per metre (cm/m). The name for this unit is the “prism dioptre“ for which the symbol is “A“. 3.9 spherical power lens: Lens bringing a paraxial pencil of parallel rays to a single point focus. NOTE 8 This definition c
29、ould also apply to single-vision aspheric lenses. 3.10 astigmatic power lens: Lens bringing a par- axial pencil of parallel rays to two separate line foci mutually at right angles and hence, unlike a spherical lens, having two principal powers. NOTE 9 One of these powers may be zero, with the corres
30、ponding focal line at infinity. Lenses referred to as toric lenses, sphero-cylindrical lenses, and cylinder lenses are all astigmatic lenses. 3.1 1 centration error of the instrument: Residual prismatic error of the instrument with no lens in place. 4 Design requirements and recommendations for gene
31、ral purpose focimeters 4.1 The measuring range shall include vertex pow- ers with a range from at least -20 D to +20 D and prismatic powers from O to at least 5 A. 0 IS0 The instrument shall be capable of measuring the axis direction (see IS0 8429) of cylindrical lenses between O“ and 180“. For pris
32、ms it shall be possible to deter- mine the direction of the base setting between O“ and 360“. 4.2 For continuously indicating focimeters, the dioptre scale shall have a scale interval not greater than 0.25 D and shall be readable to the accuracy given in tables 1 and 2. For axis directions (see ISO8
33、4291, the scale interval shall not exceed 5“ and shall permit interpolations to be made to the nearest degree. For prismatic power readings the interval shall not exceed 1 A. 4.3 For digitally rounding focimeters in the range from +IO D to -10 D, each increment of the digital display shall be not mo
34、re than 0,125 D. In the range outside +IO D, each increment shall be not more than 0,25 D. The display shall show at least two decimal digits. For axis directions, the increment of the digital display shall be 1“. The increment for the prismatic power shall be not greater than 0,25 A. 4.4 The instru
35、ments shall be designed so that it is possible to measure lenses with a diameter of at least 80mm and a thickness of at least 20mm. Trans- lational movements of the lenses on the lens support of not less than 30 mm in a direction perpendicular to the optical axis and to the adjusting rail shall be p
36、oss- ible, starting from more than 1 O mm below the optical axis of the instrument (see figure 1). Dimensions in millimetres Figure 1 - Permissible movement of the adjusting rail 2 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical
37、 Standards 1/9972545001 Not for Resale, 04/25/2007 01:30:41 MDTNo reproduction or networking permitted without license from IHS -,-,- 0 IS0 IS0 8598:1996(EI 4.5 The design of the lens support shall not ad- versely affect the accuracy of measurement by intro- ducing excessive sagittal error. 13 With
38、some lens materials, if the light source used in the focimeter is not centred on one of the reference wavelengths, correction may be necessary to meet the tolerances. NOTES 10 The test lenses described in IS0 9342 may be used to verify this requirement in the case of a lens support d e signed for sp
39、ectacle lenses. The test lenses have back surface curvatures similar to those used on spectacle lenses in general use. 1 1 An example of a suitable lens support for spectacle lenses is shown in figure 2. 5.2 Continuously indicating instruments Continuously indicating instruments, when tested over th
40、eir entire measuring range by means of test lenses as specified in IS0 9342, shall give readings for vertex power and prismatic power which shall not deviate from the nominal values of the test lenses by more than the limits given in tables 1 and 2, respec- tively. Table 1 - Tolerances of measured v
41、ertex power for continuously indicating instruments Values in dioptres (D) I Measuring range of vertex power I Tolerances I l + l d2 I I 1 + 5 I a - 10 s + 10 f 0.09 I- d, d , = 6 mm to 9 mm d2 = d, - (0.5 mm to 1 mm) d3 = (dl + d2J /2 r = d, - d,) i 4 I f0,12 B - 15 s+15 I I f 0.18 a - 20 I d +15 +
42、 20 Figure 2 - Example of a lens support for spectacle lenses Table 2 - Tolerances of measured prismatic power for continuously indicating instruments Values in prism dioptres (A) 5 Accuracy requirements 5.1 General I Measuring range of prismatic power I Tolerances I O 4 5 I I Vertex and prismatic p
43、owers shall be displayed and shall be referred to either the green mercury line Ae = 546,07 nm or to the yellow helium line & = 587,56 nm (see IS0 7944). 5 d 10 10 d 15 I I If the requirements of table 1 are not met for both wavelengths the reference wavelength used for calibration shall be indicate
44、d. 15 d 20 I Ot4 I The tolerance or deviations of reading given in tables 1 to 4 shall apply to the measurement of vertex powers and prismatic powers of spectacle lenses of all materials. 20 I 0,5 I 5.3 Digitally rounding instruments NOTES The deviations of the lens power readings from the nominal v
45、alues of the test lenses shall not exceed the values given in tables 3 and 4 over the entire measuring range of the instrument. 12 The tolerances or deviations of reading for vertex power and prismatic power, given in tables 1 to 4, corre- spond to the application of the test lenses specified in IS0
46、 9342 with the respective nominal power. 3 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:30:41 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0
47、8598 96 H Y851903 0669393 253 Measuring range of vertex power IS0 8598:1996(E) Deviation from nominal value of the test lens for increments for increments of 0.25 I of 0,125 NOTES 14 For the testing of digitally rounding focimeters it is essential that the test lenses have exact values in integer mu
48、ltiples of 0,25 D. otherwise the data of tables 3 and 4, which are based on statistical considerations, are not valid. 15 The expression “deviation of reading“ is used to clarify that this does not mean tolerance. However, the given deviations of reading are based on the same tolerances as given for
49、 continuously indicating focimeters in tables 1 and 2. CO 8 - 5 e - 5 a - 1 0 Table 3 - Permissible deviations of measured vertex power reading from the nominal value of the test lenses for digitally rounding instruments Values in dioptres (D) 0,o 0,o 0.0 f 0,125 o + 5 + 2 0 I i0.25 I f0.25 I If an instrument operates in bot