MadSci Network: Neuroscience

Re: Can lack of light cause blindness?

Date: Thu May 17 20:30:51 2001
Posted By: Amanda Kahn, Grad student, neuroscience, UCSF
Area of science: Neuroscience
ID: 988314271.Ns

Hi Kumaran!

In a sense, this experiment has been done on deep-sea/cave-dwelling species.  
Creatures who live in perpetually dark surroundings tend to have poor or non-
existent eyesight.  They may have vestigial eye structures, but the light-
detecting function is impaired.  (They find their food using tactile senses, or 
by generating their own bioluminescence).  There's even a type of fish (blind 
cave fish) whose eyes fall out as they age.

Why is this so?  Eyes consume a tremendous amount of cellular resources -- 
proteins are constantly synthesized and metabolized, and energy-storing molecules 
are rapidly turned over.  If eyes are not actively detecting light, then the 
maintenance of the eye structures is a waste of cellular resources.

It is conceivable that some of these changes could take place over the course of 
a human life, if a person were deposited at the bottom of the ocean or deep in a 
cave.  The cellular machinery that controls production of eye proteins could 
gradually decrease output, particularly if the person's nutritional state was 
compromised.  I'd probably be pretty hungry at the bottom of the ocean or deep in 
a cave ...

Amanda Kahn

references: There's a lot on the web about blind cave fish (they're popular among 
aquarium enthusiasts).  For information about deep sea creatures, try doing a 
google search for "deep ocean" and eyes, to get articles such as:


Current Queue | Current Queue for Neuroscience | Neuroscience archives

Try the links in the MadSci Library for more information on Neuroscience.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-2001. All rights reserved.