The chromaticity co‐ordinates for the standard illuminants SA, SB and SC of one British and fifteen Egyptian observers

Ishak, I. G. H.

doi:10.1113/jphysiol.1951.sp004650

Cited by 11 publications

(2 citation statements)

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“…I t has been shown th a t darkly pigmented races have a denser m acular pigm entation of the fundus of the eye (Silvar & Pollack 1967). Furtherm ore, spectral sensitivity in darkly pigmented races is reduced in the short wavelength p a rt of the spectrum, particularly in the blue (Ishak 1951;1952;D odt et al 1959). This is m intraocular pigm entation.…”

Section: Animals and Humans Living In Bright Environment Have Darker Eye Pigmentationmentioning

confidence: 99%

Carotenoid pigments: their possible role in protecting against photooxidation in eyes and photoreceptor cells

Kirschfeld

1982

Proc. R. Soc. Lond. B.

131

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The effect of light on animal tissues is ambivalent. Light is necessary for many functions, e. g. for vision and, as in the flagellate halobacterium, to gain energy. But light is potentially dangerous: it is capable of destroying cells or their components by photooxidation, especially in the presence of sensitizing pigments such as haems and cytochromes, which are ubiquitous in aerobic cells. Several different examples are discussed to show how a compromise is achieved in animal tissues that for functional reasons receive high exposure to light. Carotenoid pigments, present in many eyes and photoreceptors, seem especially suited to protect against the deleterious effects of light because they absorb the dangerous short wavelength part of the light spectrum. In plant tissue, carotenoids are also well known to be capable of ‘quenching’ photoexcited states of sensitizing pigments and of oxygen, a function that they might have also in animal tissues. A consequence of the considerations is that whenever animal tissues are exposed to higher than usual light levels and/or oxygen pressures cellular damage might occur. Examples are discussed; strategies to circumvent the deleterious effects by photooxidation follow directly from the arguments.

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Section: Animals and Humans Living In Bright Environment Have Darker Eye Pigmentationmentioning

confidence: 99%

Carotenoid pigments: their possible role in protecting against photooxidation in eyes and photoreceptor cells

Kirschfeld

1982

Proc. R. Soc. Lond. B.

131

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“…So far as I know, this was the first study of the colour-matching characteristics of a group of non-white subjects that could be compared with the characteristics of the 1931 CIE standard observer and Ishak concluded that the main difference could be attributed to a greater density of the yellow macular pigment among the Egyptian observers than that of the standard observer. He did, however, report a significant difference in the green and blue chromaticity coordinates of the spectrum colours that could-not be attributed to macular pigment differences (Ishak, 1951(Ishak, , 1952a.…”

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confidence: 92%