How Eyes Evolved to See The World Differently

This special lab houses an impressive collection of over 60,000 different animal eyes, where disease and morphology are studied in great detail.

"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! 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.