What Is Topography?

How do we learn so much about the cornea before surgery? The answer lies in all the sophisticated scans. The shining star of all these tests is corneal topography.

Topography isn’t unique to the eyes. In fact, topography has existed for centuries. Topography is simply an elevation map showing the difference between peaks and valleys of something (typically mountains or hills on a map of land).

But topography isn’t just limited to seeing where and how high the nearby mountains are. These principles have also been applied to detect patterns in the cornea of the eye. One such pattern that topography is perfect at detecting is astigmatism.

When we think of the eyes, we think of a dome structure. And that is pretty much true. The cornea exists in a dome. But within that dome there are sometimes parts which are more elevated than other parts. One easy way to describe astigmatism is that the cornea has a football shape. Well, if the cornea is supposed to be a dome, like a basketball but instead is a football, you will have parts of the cornea which are higher than the other. If you look at a football, two parts (opposite of each other) are in fact higher than the other two sides of the football. This same thing exists on the cornea.

So how do we see astigmatism and other patterns on the cornea? Topography is the key which unlocks this map!

Related Articles