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This standard is developed according to the rules specified in GB/T 1.1-2009.
This standard replaces YY 0065-2007 Ophthalmic Instruments - Slit-lamp Microscopes, and the following technical changes have been made with respect to YY 0065-2007:
——Requirement for focus difference between the left and right observation systems is added (see criterion No.7 in Table 1);
——Requirement for optical radiation hazard is added (see 4.4);
——Requirement for minimum spot size is deleted (4.1.3 of 2007 edition);
——Requirement for spot illuminance of slit is deleted (4.1.6 of 2007 edition);
——Requirement for field diameter is deleted (4.1.5 of 2007 edition);
——Requirement for mechanical motion is deleted (4.2 of 2007 edition);
——Requirement for environment test is deleted (4.5 of 2007 edition).
This standard has been redrafted and modified in relation to ISO 10939:2007 Ophthalmic Instruments - Slit-lamp Microscopes.
Technical differences exist between this standard and ISO 10939:2007 and clauses involving these differences are indicated by vertical single line (|) at page margin. The technical differences between this standard and ISO 10939:2007 and their reasons are as follows:
——For normative references, this standard covers adjustment on technical differences so as to adapt to the technical conditions in China, which is intensively reflected in Chapter 2 - "Normative References"; specific adjustment is as follows:
? Replace IEC 60601-1 with GB 9706.1 which is identical to international standard;
——"This standard is applicable to general slit-lamp microscope." is added in Chapter 1 - "Scope".
——Chapter 5 -"Test Methods" is added. These test methods are recommended to make the requirements of this standard be operable. ISO 10939:2007 contains no test method.
Attention is drawn to the possibility that some of the elements of this standard may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This standard was proposed by China Food and Drug Administration.
This standard is under the jurisdiction of the Subcommittee on Medical Optics and Instruments of National Technical Committee on Optics and Photonics of Standardization Administration of China (SAC/TC 103/SC 1).
The previous editions of the standard are:
——WS2-285-1982;
——YY 0065-1992;
——YY 0065-2007.
Ophthalmic Instruments - Slit-Lamp Microscopes
1 Scope
This standard, together with ISO 15004-1 and ISO 15004-2:2007, specifies requirements and test methods for slit-lamp microscopes.
This standard is applicable to general slit-lamp microscope. This standard is not applicable to slit-lamp microscope accessories, e.g. photographic equipment and lasers.
This standard takes precedence over ISO 15004-1 and ISO 15004-2:2007, if differences exist.
2 Normative References
The following documents for the application of this document are essential. For dated references, only the edition cited applies. For undated references, the latest edition of the normative document (including any amendments) applies.
GB 9706.1 Medical Electrical Equipment - Part 1: General Requirements for Safety (GB 9706.1-2007, IEC 60601-1:1988, IDT)
ISO 15004-1 Ophthalmic Instruments - Fundamental Requirements and Test Methods - Part 1: General Requirements Applicable to All Ophthalmic Instruments
ISO 15004-2:2007 Ophthalmic Instruments - Fundamental Requirements and Test Methods - Part 2: Light Hazard Protection
3 Terms and Definitions
For the purposes of this document, the following terms and definitions apply.
3.1
slit-lamp microscope
instrument consisting of a microscope and a swivelling illumination system providing a slit image
3.2
visual angular magnification
ratio of the viewing angle of an object, when observed through a magnifying system with the image at infinity, to that of the object, when observed by the naked eye at a reference viewing distance of 250mm
Note 1: The visual angular magnification, Γ, can be calculated using the following equation:
Where,
σ′——the angle at which an object is seen through the entrance pupil center of microscope;
σ——the angle at which the same object is seen without any instrument at a viewing distance of 250mm.
Note 2: The visual angular magnification of the microscope comprises the magnifications of the complete system.
3.3
high eye point eyepiece
eyepiece in which the exit pupil is of sufficient clearance from the eyepiece to allow spectacles to be worn
4 Requirements
4.1 General
The slit-lamp microscope shall conform to the requirements specified in ISO 15004-1 and ISO 15004-2:2007.
4.2 Optical requirements
The slit-lamp microscope shall conform to the requirements given in Table 1.
?
Table 1 Requirements for Optical Properties
No. Criterion Requirement
1 Permissible tolerance of visual angular magnification of microscope ±5%
2 Permissible tolerance of visual angular magnification between left and right observation systems ≤3%
3 Angular difference in axis between left and right optical systems a Vertically Interpupillary distance: 60mm~66mm ≤10′
Interpupillary distance: 55mm~<60mm; >66mm~72mm ≤15′
Horizontally Convergence b ≤45′
Divergence ≤10′
4 Shift in the object plane by change in magnification ≤0.4mm
5 Focus tolerance for illumination system with respect to the mechanical rotation axis c Axial c Δα=±0.5mm
Lateral c (Δα)α=±0.35mm
6 Tolerance for foci planes of left and right observation systems (?R, ?L) including all magnifications with respect to the focus of illumination system (slit image) in any position ΔR, ΔL≤X·dd
X=2e
7 Focus difference between the left and right observation systems Δ(R, L)≤X·dd
X=2e
8 Eyepiece 1) Calibration error of dioptre scale ±0.25D at zero on the dioptre scale
2) Range for interpupillary distance adjustment 55mm~72mm
3) Range for dioptre scale adjustment (minimum) -5.00D~+5.00D
-4.00D~+2.00D for high eye point eyepieces
4) Difference in axial positions of the exit pupils between left and right observation systems ≤1.5mm
9 Slit image 1) Minimum width ≤0.2mm
2) Maximum length ≥8.0mm
3) Parallelism of the sides (for a slit image 0.2mm×0.8mm) ≤0.5°
4) Maximum width Equal to slit length
a With the eyepiece for which the slit-lamp microscope is designed.
b This requirement does not apply to those slit-lamp microscopes where, due to the design, the mechanical axes of the eyepieces are not parallel to each other.
c For explanation of criterion No.5, see Figure 1.
d Depth of field, expressed in millimetres:
Where,
N—— the numerical aperture;
Γ—— the total visual angular magnification of the microscope (see 3.2);
λ—— the reference wavelength in accordance with GB/T 10050-2009, λ=546.07nm or 587.56nm.
e X is a weighting factor.
Key:
(Δα)α=Δα sinα for a rotational angle range up to α = 45°;
OS——observation system;
IS——illumination system;
RC——rotational centre of OS and IS;
Δα——axial focus tolerance.
Figure 1 Explanation of Criterion No.5
4.3 Construction and function
4.3.1 Basic requirements
The following requirements shall apply:
a) The parallel slit edges shall be smooth and free from any imperfections when observed using the highest visual angular magnification;
b) The slit image shall be evenly illuminated;
c) No contrast decrease in the slit image caused by reflections or scattered light shall be observed;
d) The brightness and colour transmission of the left and right optical systems shall be identical;
e) At the highest visual angular magnification, the resolving power in the centre of the field shall be at least 1,800N lp/mm (N is the numerical aperture).
4.3.2 High eye point eyepiece
If the manufacturer states that the eyepiece is a high eye point eyepiece, the distance between the exit pupil of the observation system and the nearest part of the eyepiece shall be not less than 17mm.
4.4 Optical radiation hazard with slit-lamp microscopes
Slit-lamp microscopes shall comply with the light hazard protection requirements given in ISO 15004-2:2007.
It shall first be determined if the slit-lamp microscope is classified as a Group 1 or Group 2 instrument in accordance with ISO 15004-2:2007, Chapter 4. The applicable clauses of ISO 15004-2 for slit-lamp microscopes are as follows:
a) For Group 1 slit-lamp microscopes:
1) Applicable requirements of ISO 15004-2:2007 are 5.1, 5.2 and 5.4.
2) Applicable test methods of ISO 15004-2:2007 are 6.1, 6.2, 6.4 and 6.5.
3) If status is determined to be Group 1, there are no further requirements; if status is determined not to be Group 1, the additional requirements given in b) are applicable.
b) For Group 2 slit-lamp microscopes:
1) Applicable requirements of ISO 15004-2:2007 are 5.1, 5.3 and 5.5.
2) Applicable test methods of ISO 15004-2:2007 are 6.1, 6.2, 6.3, 6.4, 6.5 and 6.6.
3) ISO 15004-2:2007, Chapter 7, also applies.
If the intended use of the slit-lamp microscope includes the use of supplementary 90D lenses, an arrangement shall be made for measurement of corneal and lenticular related exposure values. The 90D lens (e.g. Volk lens) shall be at a position 7mm behind the focus plane of the slit lamp with the maximum illumination field. The exposure measurement then is to arrange 7mm behind the 90D lens on the spot of the minimum size of the illumination field.
Foreword I
1 Scope
2 Normative References
3 Terms and Definitions
4 Requirements
5 Test Methods
6 Accompanying Documents
7 Marking
