What Is Topography?

Mr Glenn Carp – “Topography is a type of scan which looks at the curvature of the cornea.  It is able to look at certain shapes that the cornea presents with and in turn it can look and help us screen for certain conditions like keratoconus where there is some irregularity to the overall shape of the cornea.  Most people have a pretty rounded, spherical type shape or if they do have a slight steep and ridge like in astigmatism, it is in a fairly regular distribution whereas topography can actually look at the curvature of the whole cornea, determining if there are any irregular areas.”

Topography Explained Further…

Topography measures the depth of the surface of your eye, your cornea. The picture produced by a topography machine looks like a map of a mountain range, with the different elevations shown in contrasting colours.

Topography is one of the most important safety factors in determining how suitable you are for Laser Eye Surgery. The most basic kind of topography measures the shape of the surface at the front of your eye. The most detailed topography measures the shape of both the front and back surfaces of your cornea. Common topography machines are the Orbscan™, the Pentacam™ and the Galilei™.

Our laser eye surgeons chose the Orbscan II to perform corneal topography at London Vision Clinic. The Orbscan II machine provides the most detailed topography. It is the ‘gold standard’ across the world because of the sheer number of points it measures on your eye. This is the very best option for determining changes in the shape of your cornea. It provides a 3D map of your cornea, which is essential for determining whether it is too thin for surgery to be safe. We perform topography both before and after treatment.