ASCRS 2024: Comparing keratometry and total keratometry values in a large dataset

News
Video

Jascha Wendelstein, MD, discusses the outcomes of a study comparing K and TK measurements

At this year's ASCRS 2024 meeting, Jascha Wendelstein, MD, spoke with Ophthalmology Times Europe about the outcomes of using keratometry versus total keratometry values, in both special and normal eyes.

Editor's note: The below transcript has been lightly edited for clarity.

Hello there, my name is Jascha Wendelstein. I'm currently practicing in Switzerland and Austria: university clinic in Austria, private practice in Switzerland. My main base, or my main interest, is cataract surgery, IOL calculation and refractive surgery, with a bit of corneal surgery and keratoconus too. A very big study, which was published and also presented here [at ASCRS] was a study that compared K [keratometry] and TK [total keratometry] values.

Now, why did we compare them? Previous studies of our group, which was basically Oklahoma City University, David Cooke [Great Lakes Eye Care, St. Joseph, Michigan], and myself, we looked at K and TK values, in special eyes. Basically eyes after laser vision correction, eyes after DMEK surgery, and also with keratoconus, so to say. And we saw that TK values work in all those eyes. They were better than the K values. But the next question is, are the TK values overfitted? Do they still work in normal eyes to change something? And we were able to acquire quite a large data set for it 117,000 eyes, which we assembled in that, and we looked at the differences between K values and TK values.

We found that 94% of those eyes were within a quarter diopter, 99% of the eyes were within half a diopter. So no big differences. The 1% was explained by very few eyes that were suspicious for previous laser vision correction, but with a retrospective study, of course you'll get those eye. The rest of the eyes, obviously, no big differences. So K values seem to be fine, TK values seem to be better, not only in special eyes, also in normal eyes. So, greenlight for the use of TK values as the as the default value in your IOLMaster 700 [ZEISS]. Make use of it. You can do it. Have good success using them!

Newsletter

Join ophthalmologists across Europe—sign up for exclusive updates and innovations in surgical techniques and clinical care.

Recent Videos
Christine Curcio, PhD, of the University of Alabama at Birmingham Heersink School of Medicine, shares histology update and revised nomenclature for OCT with Sheryl Stevenson of the Eye Care Network and Ophthalmology Times
SriniVas R. Sadda, MD, FARVO, shares key points from his retina presentation at the International SPECTRALIS Symposium
Robert Sergott, MD, describes fluorescence lifetime imaging ophthalmoscopy (FLIO) and the International SPECTRALIS Symposium – And Beyond (ISS) in Heidelberg, Germany.
Rayaz Malik, MBChB, PhD, a professor of medicine at Weill Cornell Medicine - Qatar, spoke with Ophthalmology Times Europe about his presentation. It's titled "An eye on neurodegenerative diseases: Challenging the dogma" at the International SPECTRALIS Sympsoium. In conversation with Hattie Hayes, Ophthalmology Times Europe
Anat Loewenstein, MD, describes her presentation on remote imaging for age-related macular degeneration and geographic atrophy at the International SPECTRALIS Symposium, in conversation with Hattie Hayes of Ophthalmology Times Europe
Tyson Brunstetter, OD, PhD, a US Navy Aerospace Optometrist at the NASA Johnson Space Center in Houston, Texas, shares key takeaways from his keynote at the International SPECTRALIS Symposium (ISS)
Rayaz Malik, MBChB, PhD, shares his presentation, titled An eye on neurodegenerative diseases: Challenging the dogma, at this year's International SPECTRALIS Symposium
At the Retina World Congress, Siegfried Priglinger, MD, speaks about ensuring the best outcomes for preschool-aged patients
At the 2025 ASCRS meeting, Robert Ang, MD said small aperture IOLs can benefit all patients, especially those with complex corneas or who have undergone previous corneal refractive surgery
Viha Vig, MBChB graduate student at the University of Auckland, New Zealand, discusses her poster presentation on the relationship between mitochondiral disease, Alzheimer disease, and other types of dementia.
© 2025 MJH Life Sciences

All rights reserved.