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in the text below, the authors equate chromatic aberration and the spectral sensitivity of the human eye. Aren't these two very different phenomena though? They also propose a so-called "relative myopia" and "relative farsightedness". Are these claims valid? Does chromatic aberration even pertain to the human eye? I can only find sources that discuss this phenomenon within the field of photography.

I would very much appreciate any citations that debunk this text.

Here are my summed-up points that I, as an amateur without any formal education or training in ophthalmology, find problematic. I think that the text:

  1. equates chromatic aberration and the spectral sensitivity of the human eye – which are two very different phenomena
  2. proposes that chromatic aberration (which is a property of a lens) happens in all human eyes and it causes a so-called "relative myopia" and "relative farsightedness" – terms I cannot seem to find online. Would not this result in all of us seeing blurred colourful fringes and haloes around objects, just like you can see in a photograph taken by a camera that strongly exhibits chromatic aberration? I can't find a study to support my point though.
  3. states that the human eye is most sensitive to the yellow-green wavelength range because this range is most predominant in the Sun's spectrum – but isn't it so because the weighted function of the spectral sensitivity of our cones simply lies around 555 nm? Maybe these studies might help, I am not sure [1,2]. They also vaguely state that this yellow-green range has "the most favourable effect on humans" which is confusing, what does that mean? For example, "favourable" during the night certainly is light devoid of blue and green wavelengths that suppress melatonin secretion [3,4,5] – so "favourable" is debatable without being specific.

The text:

When designing lighting, the chromaticity of the light used must be carefully considered. Due to the predominant yellow-green component in sunlight, the human eye is most sensitive to the yellow-green wavelength range and this light also has the most favourable effect on humans. On the contrary, red or blue light of the same intensity is much more difficult to perceive. In the eye, light with a high proportion of blue wavelengths falls in front of the retina, causing so-called relative myopia; on the contrary, light with a high ratio of red wavelengths falls behind the retina and causes relative farsightedness. This phenomenon is also called chromatic aberration (also a chromatic defect or colour defect) and it is necessary to keep in mind when designing the lighting systems or electronic displays.

The text is not published anywhere, it is an excerpt I got sent which I translated into English.

References

[1] Stockman, A., & Sharpe, L. T. (2000). The spectral sensitivities of the middle- and long-wavelength-sensitive cones derived from measurements in observers of known genotype. Vision Research, 40(13), 1711–1737. https://doi.org/10.1016/S0042-6989(00)00021-3

[2] Hofer, H., Carroll, J., Neitz, J., Neitz, M., & Williams, D. R. (2005). Organization of the human trichromatic cone mosaic. Journal of Neuroscience, 25(42), 9669–9679. https://doi.org/10.1523/JNEUROSCI.2414-05.2005

[3] Brainard, G. C., Hanifin, J. R., Greeson, J. M., Byrne, B., Glickman, G., Gerner, E., & Rollag, M. D. (2001). Action spectrum for melatonin regulation in humans: Evidence for a novel circadian photoreceptor. Journal of Neuroscience, 21(16), 6405–6412. https://doi.org/10.1523/jneurosci.21-16-06405.2001

[4] Al-Naggar, R. A., & Anil, S. (2016). Artificial light at night and cancer: Global study. Asian Pacific Journal of Cancer Prevention, 17(10), 4661–4664. https://doi.org/10.7314/APJCP.2016.17.10.4661

[5] Bonmati-Carrion, M. A., Arguelles-Prieto, R., Martinez-Madrid, M. J., Reiter, R., Hardeland, R., Rol, M. A., & Madrid, J. A. (2014, December 17). Protecting the melatonin rhythm through circadian healthy light exposure. International Journal of Molecular Sciences. MDPI AG. https://doi.org/10.3390/ijms151223448

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    $\begingroup$ Which of the references actually contains the text you quote - 1? $\endgroup$
    – MattDMo
    Jan 11 at 15:31
  • $\begingroup$ @MattDMo it is not an English text and it does not come a from a published work – it is just something I got sent. $\endgroup$
    – Fipah
    Jan 11 at 20:45
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    $\begingroup$ OK, then you need to edit your question clarify it. All quotes need to have attributions. $\endgroup$
    – MattDMo
    Jan 12 at 21:23
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There are two phenomena described in the quoted text, and while there is some relationship between them, they are indeed distinct: spectral sensitivity of the human eye, and longitudinal/axial chromatic aberration of the eye resulting from variation of refractive index of the lens by wavelength. I found the following on Physics.SE:

https://physics.stackexchange.com/questions/12602/do-eyeballs-exhibit-chromatic-aberration

which links to this interesting page:

https://www.telescope-optics.net/eye_chromatism.htm

Note that the existence of such aberration is a purely optical phenomenon, but biologically, the structure of the eye (in particular, the distribution of retinal cone cells, and neural processing) compensates for the resulting perception to a significant extent.

That said, I think the way the information is explained in the quoted text is not particularly clear, as it sort of jumbles the concepts together. If you want to learn more, do a web search for key phrases such as "human spectral sensitivity" and "human lens dispersion."

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