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Biology/Light and human eye

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Expert: - 9/30/2008


Question
Hi, I would like to know 1) What are the spectrum's of light that the human eye cannot see? 2) What are the spectrum's of light the will not damage the human eye assuming this is not direct and or extended exposure?
Thanks, Gary

Answer
Dear Gary,

The human eye is sensitive to wavelengths between about 380nm (violet) and 750nm (red).  Anything shorter or longer than that is invisible, though there is some variation in sensitivity among humans.

Short wavelengths are potentially more damaging to living tissue (such as the eye) than long wavelengths.  Hence, anything shorter than about 380nm (ultraviolet, x rays, gamma rays) are to be avoided.   Wavelengths longer than red (infrared, radio waves) should not be harmful to tissues, though there is some possibility that microwaves (between infrared and radio waves in wavelength) can harm tissues by increasing molecular vibration and heating them up.

Hope that helps.

Dana

Biology

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Dana Krempels, Ph.D.

Expertise

I can answer biology-related questions in the areas of evolution, zoology, botany, genetics, and ecology. But I don't answer homework questions or provide ideas for your science fair projects. So students please do your learning the right way by reading your text assignments and studying!

Experience

At the University of Miami, I teach Evolution and Biodiversity, Botany, Zoology, Genetics, Ecology, and a variety of seminars (e.g., the Biology and Evolution of Human Gender Roles).

Education/Credentials
I have a B.S. in Biology and an A.B. in English from the University of Southern California (1980). I earned my Ph.D. in Biology in the area of evolutionary biology/visual physiology from the University of Miami in 1989.

Past/Present Clients
I am currently an "expert" in both the "Rabbits" and "Wild Animals" categories.

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