MadSci Network: Genetics

Re: is lightbrown eyecolor next after hazeleye when going from light to dark ?

Date: Mon Apr 17 14:13:15 2000
Posted By: Tom Stickel, Grad student, Optometry, Indiana University School of Optometry
Area of science: Genetics
ID: 955733931.Ge

	I'm going to go ahead and run down the list 
of common eye colors, and we'll deal with the 
hazel/light brown controversy when we get there.  
Since I'm on the hazel/light brown borderline 
myself, I'm interested in the question too.
	The following is from Remington's 
"Clinical Anatomy of the Visual System," 1st 
edition, published in 1998 by Butterworth-
	"Iris color depends on the cell and pigment 
density and on the collagen arrangement and 
density...If the iris is heavily pigmented, the 
(front) surface appears brown and smooth, even 
velvety, whereas in a lighter iris, the collagen 
(fibers) are evident and the color ranges from 
greys to blues to greens depending on density of 
pigment and collagen...In all colored irises, the 
two epithelial layers are heavily pigmented. Only 
in the albino iris do the epithelial layers lack 
	The pigment we're discussing here is 
melanin, produced by little cells called 
melanocytes in your iris.  Collagen is a 
structural protein in your iris, as well as 
everywhere else in your body.
	Anyway, it looks like the lightest eyes are 
albino, because they have almost transparent 
irises.  The next darkest is grey, then blue, then 
	As for hazel, my dictionary defines it as a 
reddish-yellow brown.  Eyes that I call hazel 
usually seem to have some green mixed in with 
them too.  True hazel eyes have an orange tint to 
the brown which really makes them stand out.  
That textbook by Remington doesn't even 
mention hazel, leading me to believe that the 
official academic opinion is that hazel is just a 
very light colored, orange-ish type of brown.
	As for distinctions between different types 
of browns, that's a little tricky.  People with more 
pigment in the rest of their body, such as 
Africans, Indians, and Southeast Asians, have 
distinctively browner irises than the typical 
Caucasian "brown eye."  People with more 
pigment tend to have that 'velvety' dark brown 
look  mentioned above, while Caucasian brown 
eyes  are usually lighter brown, or even 'hazel.'
	But, like hair color, there are a million 
shades of brown, and eyes come in all ranges 
from light greenish brown to almost black.  If 
you really want to figure out the exact shade of 
brown eye that someone has, the best way would 
probably be to take them to the paint store and 
compare color chips!  So keep looking at eyes 
that are brown, and you'll start noticing subtle 


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