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Chapter 12: Corneal topographic astigamtism (CorT) Anterior and Total

Practical Astigmatism: Planning and Analysis book order -

CorT Anterior and Total, corneal topographic astigmatism (CorT), Simulated Keratometry (SIm K) The measurement of corneal astigmatism is most important when planning Toric IOL selection. What is your approach to measuring the most accurate corneal astigmatism parameter? On any patient’s visit you are going to take multiple corneal astigmatism readings, manual keratometry, corneal topography, IOL master, Lenstar. There are a lot of ways of measuring the corneal astigmatism so you take them all to see which is the most representative. Over time I have found the most accurate measure to be corneal topographic astigmatism or CorT where instead of using a 3mm zone with only one ring as is the case for simulated keratometry measures, all the rings of the corneal topographer are used taking a vectorial average of all the measures. How does a doctor calculate the CorT parameter? CorT Anterior or CorT Total which includes the posterior cornea can be calculated by having the iAssort interface with the particular topographer or tomographer you use. The CorT calculation uses the measured data only without any extrapolation.