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Normal Eye Corneal Topography
We have an available tool called corneal topography. This is latest generation and altimetric which serves to extrapolate a whole series of values, indexes and figures relative to the cornea which is an anterior segment of the eye.
The corneal topographer is a machine that manages to encode everything that is transparent. It practically gives us information on the most anterior part of the eye. This is the one we can measure with an instrument equipped with cameras, such as the topographer.
This altitudinal topograph combines two technologies. The first technology, an ancient one, is that of Placido's discs. These concentric circles are projected onto the cornea and reflected by it and the machine captures them through a camera that is in the center. The other technology is much newer and is that of the Scheimpflug camera, in which a rotating camera is able to capture a whole series of measurements relating to the front and transparent part of the eye.
These measurements are captured by the computer and processed. This very sophisticated and very powerful machine is able to provide us with a whole series of measurements, which is a screen appears with a series of numerical values, which the ophthalmologist and the orthoptist must know how to read and interpret and it is a real map of colors. This color map represents the surface of the cornea and we can select a whole series of parameters. Usually the corneal topography is used with six maps, in which the anterior and posterior surfaces of the cornea are represented, corneal thickness, anterior tangent, anterior and posterior sagittal, anterior and posterior refractive elevation, the space of the anterior chamber and finally the background.
Practically, this is what is photographed by the machine. This is Placido's disc with Placido's circles that are reflected. Depending on how they are reflected, the computer is able to interpret and define what is the radius of curvature of the cornea.
The smaller the reflexed circles are, the more the cornea is curved. The larger the reflexed circles are, the more the cornea is flat. This is the principle on which the Placidum disk is based. It provides a corneal topography that can be tangential anterior or front axial depending on the type of computer processing. However, it still gives an answer of what is the shape of the cornea in the sense of curvature which is the radius of curvature at that point of the cornea.
If we look at it in three dimensions, we see how the cornea, in a healthy subject like this, is represented as fundamentally spherical and a little more curved on one axis and a little more flat on the other (because it is an astigmatic patient). Fundamentally, it is green and a little bit redder in the center.
The corneal topography is expressed in diopters. Here, on the left the color scale is represented in which there are the coldest colors that show the flattest part of the cornea. The intermediate colors represent the intermediate part and the warmer colors represent the most curved part of the cornea...
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Graduated in Medicine and Surgery from the University of Turin in 1996 and specialised at the same University in Ophthalmology in 2000. Is one of the best and most successful Italian refractive surgeons and, in particular, deals with:
► Cataract surgery with high-tech IOL implants:
- Performed the first Panoptix trifocal lens implant procedure
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► In June 2016, he implanted the first ICL Evo+ V5 lens implants in Italy
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