How to dissect an eye from a cow

At the Exploratorium, they dissect cows’ eyes to show people how an eye works. If you can't help but try this at home after watching this video tutorial, wash your hands after the dissection. Wear latex gloves if you have cuts in your hands.

The white part of the eye is the sclera, the outer covering of the eyeball. The blue is the cornea, which starts out clear but becomes cloudy after death.

Six muscles attached to your eyeball move your eye so you can look in different directions. Cows have only four muscles that control their eyes. In the cow’s eye dissection, we cut away all the fat and muscle so that we can see the eyeball.

A clear tough surface called the cornea covers the front of your eye and protects your eye. If you make a cut in the cornea, a clear fluid oozes out. That’s the aqueous humor, which is made of protein and water. The aqueous humor helps give the eye its shape.

Cut through the sclera and divide the eye in half, right around the middle. The cornea will be on the front half of the eye. The cornea is made of many layers of tissue. Watch the video to hear the crunch of a scalpel cutting through those layers.

Then check out the iris. The black spot in the middle of the iris is the pupil, a hole through the iris that lets light into the eye. In dim light, the pupil opens wide, letting lots of light in.

Next, the lens. The clear goo around the lens is the vitreous humor. The eyeball stays round because it’s filled with this clear goo.

The lens of the cow’s eye (like the lens of your eye) is shaped like the lens of a magnifying glass. It’s thicker in the middle than it is at the edges.

The retina is attached to the back of the eye at just one spot. It’s called your blind spot. Because there are no light-sensitive cells at that spot, you can’t see anything that lands in that place on the retina. At the blind spot, all the nerves from the retina join to form the optic nerve.