How do Chameleons eyes work

Another surprising fact about Chameleons are the uniqueness of structure and ability of its eyes.  Chameleons have eyes that move and view independently of each other.   That is to say that the creature can move one eye to one direction, and the other eye to a totally different direction at the same time.  This kind of ability provides it with approximately 360-degree vision (Ask Nature).  

The eyes of the Chameleons are actually made up from one large cone shaped eye lid.   It covers virtually the whole eye, leaving a tiny hole to expose the pupil.   Having an eyelid for protection of the pupils, the Chameleon can watch a predator coming its way, and at the same time, examine its surroundings for the best escape routes.   Being one of the most visually-oriented lizards (Chameleon vision, Wikipedia), the creature primarily utilizes its eye-abilities during predator avoidance and prey capture.

One of the primary striking features of the Chameleon eye is the presence of the negative lens.  However, note that although the lens is negative or concave, the cornea is actually positive.  The combination of both gives this creature an unparalleled eye sight.  In fact, the Chameleon eyes are considered to have the highest image magnification among many other vertebrate’s eyes.  Their eyes focus extremely quickly, effectively zooming in on their prey for a much better look and due to the shape of the lens in their eyes, Chameleons can see a large and clear image and this obviously helps when targeting its next meal.  When the Chameleon spots a cricket, locust or meal worm (which can be as much as 10 meters away) it turns its head to face the prey.   The Chameleon will then point both eyes directly at the target, switching to stereoscopic or binocular vision.   The Chameleon uses its binocular vision to increase depth perception and helps the Chameleon to aim with pin point accuracy.

Further to this, Chameleons are known to see in the ultraviolet range too (Devi Stuart-Fox, University of Melbourne), an ability that is quite unique in the animal world! Having lived in the world for more than 80 million years (Chameleons, NWF), the creature has always been an interesting topic among scientists.  Moreover, studies find that Chameleons have the ability to switch between synchronous and uncoupled saccadic eye movements.  That is something totally unique, and not witnessed in case of any other vertebrate in the world.

 

References:

1) “EYES GIVE 360˚ VISION: CHAMELEON.” Ask Nature.  Ask Nature.  Web.  1 May 2014
2) “Chameleon vision.” Wikipedia.  Wikimedia Foundation, Inc., 20 April 2014.  Web.  1 May 2014.
3) MacKenzie, Debora.  “Chameleons’ colourful flashes are social signals.” New Scientist.  Reed Business Information Ltd. 29 January 2008.  Web.  1 May 2014.
4) Bishop, Gerry.  “Chameleons.” NWF.  National Wildlife Federation.  Web.  1 May 2014.

Images:

1) Main image supplied by Scott Cromwell