What does the Pentacam measure?

Explanation Pentacam

The measurements with the Pentacam are very important to be able to follow the progression of keratoconus. This device measures several things:

It measures:
1. The thickness of the cornea and cone
2. The curvature and bulge of the cone at the back of the cornea
3. The curvature and bulge of the cone at the front of the cornea.

Below is an example of these measurements:

The 4 Maps Refractive shows 4 images of four different measurements.

1. The axial map shows the topography of the anterior cornea.
2. The elevation front shows how much the cone protrudes above the normal shape of the cornea
3. The elevation back shows how much the cone protrudes above the normal shape of the back of the cornea
4. The corneal thickness shows the thickness of the cornea and of the cone.

We know about keratoconus, that it starts with a thinned part of the cornea, after which the back of the cone first forms and later the front of the cone also begins to protrude.

This allows the ophthalmologist to assess the most essential aspects of the cone.

The Pentacam also has special software that is intended to analyze the cone very precisely. This software is written by Dr. Belin and Dr.Ambrόsio, hence the name Belin/ Ambrόsio Ectasia.

The progression of the keratoconus is thus assessed by this software on three different aspects:

• Has the thickness decreased at the cone?
• Has the bulge and curvature at the back of the cone increased
• Has the bulge and curvature at the front of the cone increased

Progression is determined as determined in the past year. If there has been too long a time between the measurements, it is therefore not clear whether the progression was in the past year or if it has already taken place.

Since corneal crosslinking has the goal of stopping progression, it must be established that the progression was active in the past year.