BS ISO 10936-2:2001 pdf – Optics and optical instruments — Operation microscopes — Part 2: Light hazard from operation microscopes used in ocular surgery.
1 Scope This part of ISO 1 0936 specifies requirements and test methods for optical radiation hazards from operation microscopes which are used during ocular surgery. NOTE General requirements for operation microscopes and test methods for these requirements are specified in ISO 1 0936-1 . 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO 1 0936. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of ISO 1 0936 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 1 0936-1 :2000, Optics and optical instruments —Operation microscopes —Part1: Requirements and test methods. IEC 60601 -1 :1 988, Medical electrical equipment — Part1: General requirements for safety, including Amendment1:1991, including Amendment2:1995. 3 Terms and definitions For the purposes of this part of ISO 1 0936, the following terms and definitions apply. 3.1 auxiliary beam off-axis beam attached to or an integral part of the microscope and intended to illuminate the eye 3.2 corneal plane plane that is perpendicular to the optical axis of the instrument and that is tangential to the corneal surface closest to the instrument when in normal use 3.3 photoretinitis retinal photochemically induced injury resulting from intense retinal radiant exposure NOTE Photic maculopathy is a term also used to describe photoretinitis in the fovea-macular area of the retina.
3.4 irradiance E at a point on a surface, the radiant energy flux incident on an element of the surface, divided by the area of that element [ISO 31 -6:1 992] NOTE Irradiance is expressed in milliwatts per square centimetre (mW/ cm 2 ). 3.5 main beam axial beam exiting from the microscope 3.6 radiance L quotient of the radiant flux d ? passing through a given point and propagating within the solid angle d ? in a given direction ? divided by the product of the area of a section of that beam on a plane perpendicular to the given direction containing the given point and the solid angle d ? (see C.1 ) NOTE Radiance is expressed in milliwatts per square centimetre per steradian [mW/(cm 2 ? sr)]. 3.7 retinal hazard limit limiting value of the spectrally-weighted source radiance of an ophthalmic instrument which, if exceeded, could cause damage at or to the retina NOTE The effect of the radiance of a source (see 3.6) will decrease as the light beam passes through an optical system due to filtering, absorption or other loss mechanism. Thus, basing the retinal hazard on the source radiance ensures that the radiance at the retina cannot exceed the source radiance. 3.8 spectral radiance L ? (?) value of the radiance L (3.6) of an infinitesimal wavelength interval, at any given wavelength in the spectrum, divided by the range of that interval [L ? (?) = ? L / ? ?] NOTE Spectral radiance is expressed in milliwatts per square centimetre per steradian per nanometer [mW/(cm 2 ? sr ? nm)]. 3.9 spectrally-weighted photochemical aphakic source radiance
4 Requirements for optical radiation hazard 4.1 General The operation microscope shall comply with the requirements specified in 4.2, 4.3 and 4.4. The limit values given in 4.2 are considered acceptable with respect to the risks when weighted against the performances intended. The requirements in IEC 60601 -1 apply to this part of ISO 1 0936, with the exception of this clause which replaces clauses 32, 33 and 34 of IEC 60601 -1 . 4.2 Limit values Limit values apply to radiation from the operation microscope used to illuminate, view or photograph the human eye with visible light (380 nm to 700 nm) and in which the full beam homogeneously illuminates a circular pupil of diameter 8 mm. These limits apply to each light source intended to illuminate the eye and attached to the operation microscope, including the main and auxiliary beams, and are as follows. a) Short wavelength limit: the amount of radiant power exiting the instrument in the portion of the spectrum from 305 nm to 400 nm shall have an irradiance no greater than 0,05 mW/cm 2 as measured in the corneal plane when the operation microscope is operating at maximum intensity 1 ) and at maximum aperture. b) Long wavelength limit: the amount of radiant power exiting the instrument in the wavelength range 700 nm to 1 1 00 nm shall not exceed either the amount of energy exiting the instrument in the range between 380 nm and 700 nm or 1 00 mW/cm 2 , whichever value is the smaller. The energy shall be measured in the corneal plane when the instrument is operating at maximum intensity 1 ) and maximum aperture. If, due to stops or other obstructions of the beam, a pupil of less than 8 mm diameter is illuminated, the limit values may be increased by the ratio of the area of an 8 mm pupil divided by the true area illuminated.