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% Psychtoolbox:PsychAnsiZ136MPE.
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% Partial and in progress implementation of Ansi Z136.1-2007 standard for computing
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% maximum permissable exposure.
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% *****************************************************************
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% a) Individuals using these routines must accept full responsibility
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% for light exposures they implement. We recommend that values computed
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% with these routines be carefully checked against independent calculations.
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% We have done our best to follow the standard, but it is very complex and
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% there may be errors.
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% b) As of March, 2013, these routines are still very much a work
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% in progress and should thus be treated with special caution. See
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% AnsiZ136MPEBasicTest and AnsiZ136MPEDeloriTest, both for test
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% code, and for comments about points of uncertainty.
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% c) Particularly obscure to me at present is the limiting cone aperture
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% section described with an asterisk in Table 2 of the 2007 standard
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% d) The field's knowledge of safe light levels is evolving, and it is important
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% to keep abreast of current research and not to rely soley on the
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% Ansi standard. In particular, note that there
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% are reports of disrubption at light levels below the limits specified
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% in the Ansi 2007 stanard. See for example:
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% Morgan et al., (2008), IOVS, 49, 3715-3729.
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% Morgan et al., (2009), IOVS, 50, 6015-6022.
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% Hunter et al., (2012), Prog. Ret. Eye. Res., 31, 28-42.
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% e) Apparently a new version of the Ansi Z136 standard is forthcoming,
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% but I do not have information as to what changed.
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% f) The Z136 standard is for laser light, which is coherent and monochromatic.
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% Different standards apply for broadband lights. Two relevant references are:
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% ISO 15004-2:2007, Ophthalmic instruments -- Fundamental requirements and
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% test methods -- Part 2: Light hazard protection.
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% ICNIRP (International Commission on Non-Ionizing Radiation Protection) Guidelines,
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% (1997), Guidelines on exposure to broad-band inchoherent optical radiation (0.38 to 3 uM),
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% Health Physics, 73, 539-554.
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% The second seems a little old, but is the most recent ICNIRP guideline for broadband
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% that I could easily locate.
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% - David Brainard, March 6, 2013.
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% *****************************************************************
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% Ansi Z136.1-2007. The standard document. The more recent Ansi Z136.8-2012
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% refers back to the 2007 document for the MPE calculations. But see
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% point d) in the notes above.
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% Delori et al., 2007, JOSA A, 24, 1250-1265. Provides explanation
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% about many of the calculations in the 2000 version of the standard.
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% AnsiZ136MPEBasicTest - Test the suite of routines. Generates many figures that should match those in the standard.
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% AnsiZ136MPEComputeCa - Compute constant Ca, Table 6
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% AnsiZ136MPEComputeCb - Compute constant Cb, Table 6
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% AnsiZ136MPEComputeCc - Compute constant Cc, Table 6
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% AnsiZ136MPEComputeCe - Compute constant Ce, Table 6
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% AnsiZ136MPEComputeExtendedSourceLimit - Compute overall MPE limit for extended sources, Table 5b
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% AnsiZ136MPEComputeExtendedSourcePhotochemicalLimit - Compute photochemical MPE for extended sources, Table 5b
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% AnsiZ136MPEComputeLimitingConeAngle - Compute limiting cone angle, Table 6
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% AnsiZ136MPEComputeT2 - Compute constant T2, Table 6
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% AnsiZ136MPEDeloriTest - Tests our computations against those from Delori's spreadsheet.
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% Copyright (c) 2013 by David Brainard