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What to do when your Keratometry readings are different from different Keratometers

Many a times a surgeon has been vexed by a dilemma, when his two different Keratometers give two different readings on both axis/meridian and K readings in diopters. It so happens that the auto Keratometer and the manual , or the Lenstar/ IOL Master readings are different in terms of axis and dioptric value of K readings. And then the surgeon does not know which reading to depend on.

Typically, in such cases, Warren Hill and other researchers have advised to stick to one trusted keratometer in practice. What if the surgeon is new, and does not have full confidence on any of the keratometer in his practice.

This dilemma now has an answer from Dr Graham Barrett, who recently introduced his ‘ K Calculator ‘ endorsed by the ASCRS website. The K calculator calculates the centroid value of the dioptric value of the K readings and axis from different Keratometer. This can then be input in the surgeons TORIC calculator of choice.

Remember, the K Calculator is not based on mean, or median mode, but on Centroid value, and hence is more accurate according to Dr Graham Barrett. Toric Calculator has an Integrated "Barrett K Calculator". The use of the K calculator is optional and can be accessed in a similar fashion to the Toric Calculator after the Patient Data has been entered, "Calculated" selected and the "View Formula" Tick Box is displayed.

The K Calculator allows the user to enter up to 3 different Devices or Keratometry measurements and displays the Ks and Cylinder Axis for each device. If the box adjacent to the individual device is ticked then the measurement will be included in an integrated K calculation when the "Calculate" button on the page is selected.

The Ks from the selected device or the integrated K value from multiple devices will be automatically entered into the Flat and Steep K fields and their respective axes for the Toric Calculation - the "Patient Data" menu will then need to be accessed and recalculated to display the recommended Toric IOL.

Image Grab from ASCRS Website