Sheep Eye Dissection

In the lab, we dissected a sheep eye. The eye below is fully intact, the cornea covering the front of the eye, and the sclera covering the rest. 

First we cut away any fat (yellow) or muscle left on the sclera, then we cut into the sclera. It was really tough and thick - much tougher than I expected it to be. After we finally made it through the sclera, we cut all the way around it, turning the eyeball into two hemispheres.

 We had to be careful to not cut the optic nerve. We got really lucky in that our cut was right where we wanted it to be. On the anterior half (left in photo), we had the part of the eye that is visible to the world. In it, was a gelatinous vitreous humor.

The vitreous humor maintains the shape of the eye. On the posterior half (right in photo) the retina on our sheep eye was still intact over the choroid coat.

 The retina is where images focused by the lens are collected. The underlying choroid coat nourishes the back of the eye. It has the tapetum lucidum, which is bluish in color and gives animals their night vision. It was fascinating to see that the retina is only connected to the eye in one spot, the blind spot. The blind spot is the spot on the retina where images cannot be focused. We then tipped the vitreous humor out of the front half of the eye. It tipped out quite easily, and we were met with the lens.

The lens focused light and is connected to the eye by suspensory ligaments. The lens will flatten or thicken depending on what needs to be seen. Now, we could also see the other side of the cornea. It was cloudy, because it was not in the living state. It is also to focus light. We could also see the ciliary body underneath it, which looked a bit like the underside of a mushroom.

The iris was brown/ black in colour, and overall the cornea had an oval shape, where humans have a circular cornea.