How Eyes Evolved to See the World Differently


We all can appreciate how important vision
is for the way we and animals perceive our environment. It’s fascinating how nature evolved and created
all these sort of specializations for every species. The eye is one of evolution’s greatest successes. It acts like a camera that focuses light,
and converts it into an electrical signal that the brain translates into images. Everything needs to work in perfect harmony
for vision to happen. But the smallest shift in those sensitive
mechanics can result in a loss of vision. Inside this special lab, scientists are studying
what happens to animal eyes that can no longer focus light. We study the disease of the eye or the ocular
tissues so that we can understand ocular disease better and treat their patients. Founded by Emeritus Professor Dick Dubielzig
and currently run by Dr. Leandro Teixeira, the work happening here is equal parts diagnostic
lab and exotic animal eye collection. We receive samples from almost every single
state in the US, clients from Europe, clients from Hong Kong. Basically, everywhere in the world. The size of our obsessions has multiplied
every year since then and continues to multiply. There are over 60, 000 different specimens
stored here. And while the majority are dog, cat and horse
eyes, there are 6,000 exotic ones like jaguars, bonobos, and even whale eyes. “This is currently the biggest eye COPLOW
has. Whoa! Look at that guy. That is beautiful. Look at that guy.” Every single day, there’s a challenge it’s
safe to say that on a weekly basis we get cases that we’ve never seen before. A day at the lab begins with a pile of unknowns,
just waiting to be opened. The first thing that we look for is the overall
shape of the eye. Is there anything distorted? Is there a mass? Is there any change in the tissue basically
from outside even before we cut? Tissue goes through an overnight processing
to a machine just to dehydrate. The paraffin enters the tissue, and then you
make a block of paraffin. We proceed to sectioning the tissue. The goal here is to have in the end a very
thin section of that tissue on a slide, stained so we can look at a microscope. We have a five headed microscope. We all sit together, look at it, read the
story of the case and try to understand what’s happening. These are two eyes from a walrus and a walrus
is a pinniped, they hunt under water using vision. So they need to see underwater and they also
need to see above water. There are some special modifications of the
eye that account for that. A lot of animals that need to see above and
below water tend to have a very flat cornea. My favorite eye is that of the chameleon. Their eyes move independently, back and forth,
and they catch insects with their tongue, which requires a good depth perception, but
they don’t use their two eyes together. There’s a staggering diversity of eye adaptations
in the animal kingdom, and it all sprung into existence during one major event: the Cambrian
Period. About 540 million years ago, life transformed
from a dull, microbial existence to an explosion of animal diversity….and the evolution of
the eye is often considered the catalyst. Understanding how life went from tiny organisms
to large complex creatures with visual systems is an ongoing field of research. Even Charles Darwin struggled with it. Ultimately, animals process light
to compete and survive. We’re looking at a high magnification image
of a lens capsule of a cat. The cat has been traumatized and the bright
magenta tissue that’s been wrinkled up is the lens cap. This process – trauma to the lens and cats
is responsible for the second most common cancer of the cat eye, which we call the post-traumatic
sarcoma. Studying this kind of tumor in cats could
have a major impact on human cancer treatment. Now we can study, what are the differences
between the lens epithelial cells in cats and humans and try to see, “Oh, this gene
is off in humans but it’s on in cats. Is that switch present in other cells that
we can turn it on and off and try to regulate cancer?” This collection of eyes is a resource for
evolutionary biologists and veterinarians alike, creating an unparalleled photographic
record, indexed by animal species. By studying the disease origins, effects and
progression, we’re helping push the field forward bit by bit. It feels good to be able to help, and to know
that all that information is getting archived in a way that we might be able to work with
and make an impact on animals’ lives.

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