On-demand webinar

Total Keratometry (TK) versus anterior keratometry – Does it really make a difference?

11 March 2024 · 33 min watch
Catarina Praefke Coutinho
Author Catarina Praefke Coutinho Biomedical Engineer at Studio Oculistico d'Azeglio, Bologna, Italy
Jascha Wendelstein, MD
Author Jascha Wendelstein, MD Specialist at the Institute for Refractive and Ophthalmic Surgery (IROC), Zurich, Switzerland

Total Keratometry (TK®) versus anterior keratometry – Does it really make a difference?

In this symposium, Dr. Jascha Wendelstein and Catarina Coutinho discuss the impact of integrating Total Keratometry values into IOL power calculation, it's impact on the accuracy of clinical results and where it really makes a difference.

Chapter 1 – Jascha Wendelstein, MD: “Utility of K vs TK in IOL calculation: From normal eyes to eyes with keratoconus or Fuchs endothelial dystrophy”

Time: 0:00 – 12:58
Dr. Wendelstein begins his talk by addressing the importance of simplifying clinical workflows and minimizing errors in IOL calculations, especially in cases of abnormal corneas like keratoconus or Fuchs endothelial dystrophy. He highlights that TK values are beneficial in achieving consistency across different eye types. While negligible differences are observed in normal eyes between K and TK values.

Time: 12:59 – 19:15
Moving on to more challenging cases, Dr. Wendelstein explores how Total Keratometry, helps with IOL Calculation in keratoconus eyes.

Time: 19:16 – 24:10
Towards the end of the discussion, Dr. Wendelstein provides tips on the best usage of TK values in DMEK cases.

Chapter 2 – Catarina Coutinho, Biomedical Engineer: “Total Keratometry in post LASIK eyes”

Time: 24:11 – end
In her talk, Catharina Coutinho demonstrates the superiority of TK values over traditional keratometry in maintaining accuracy in post-LASIK eyes. She specifically, addresses two key questions: which corneal power to use and which formula to choose for IOL power calculation in post-LASIK eyes?


  • The speakers have a contractual or other financial relationship with Carl Zeiss Meditec AG and its affiliates and have received financial support.

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