Avoid the Double Dip: Rely on VERACITY When Using Formulas That Require K1/K2 and PK1/PK2 Inputs

The menu of formulas we cataract surgeons have at our disposal allows us to select the surgical parameters that best fit a given patient’s individual circumstances. As has been written elsewhere in this Tip of the Month series, ZEISS VERACITY Surgery Planner empowers cataract surgeons to break free from the two or three formulas in their comfort zone by allowing instantaneous toggling between formulas. In using ZEISS VERACITY Surgery Planner this way, we realize the benefits of less familiar formulas without enduring the heavy lift of manual data input—all while making patient visits more efficient and precise.

Surgeons who use analog systems to prepare for surgery rely on online calculators that increase the risk of mistakenly entering inaccurate biometric data—and not only through typographic error, but also from an incomplete understanding of the precise inputs some formulas require. But surgeons who leverage the power of ZEISS VERACITY Surgery Planner have a distinct advantage: because VERACITY pulls directly from your biometric equipment, you can’t mistakenly input inaccurate data into your formulas. When it comes to formula calculation input, VERACITY has your back from start to finish.

Surgeons still calculating by hand run the risk of “double dipping” certain biometric inputs when using manual calculators—that is, they may enter Total K (TK) values rather than individually entering flat (K1) and steep (K2) corneal powers and posterior corneal curvature (PK1 and PK2). It’s easy to see how a surgeon performing manual calculations could do this: because TK is a composite of anterior and posterior corneal measurements, a surgeon trying to maximize efficiency in the clinic could opt to enter TK for all K1/K2/PK1/PK2 inputs rather than enter four distinct values individually.

But here is where manual calculations risk a double dip. The Barrett suite formulas integrate K1/K2 and PK1/PK2 values differently than a TK calculation does, the output of a formula calculated with four redundant TK values differs meaningfully from the output of a formula calculated with distinct K1/K2 and PK1/PK2 values. Double dipping risks distorting the actual keratometry measurements’ value, which may undercut efforts to maximize postoperative outcomes.

ZEISS VERACITY Surgery Planner’s default configuration automatically pulls both anterior and posterior K values from whatever biometer a particular surgeon has connected to VERACITY, eliminating the possibility that TK values disrupt calculations that don’t need them. In other words, the double dip is impossible with ZEISS VERACITY Surgery Planner.

Even if a surgeon selects TK within the planning screen, ZEISS VERACITY Surgery Planner corrects for this input by automatically selecting the anterior and posterior Ks (this only applies when a formula from the Barrett Suite is selected, due to this suite of formulas having the ability to use the actual measured values). In this case, the surgeon will see their input as “TK/ Barrett U II or Barrett True K,” and can rest assured knowing that the output will be correct thanks to ZEISS VERACITY Surgery Planner selecting the proper inputs for calculation. Of course, VERACITY is customizable to each surgeon, allowing the option to use PK or only AK as default in their calculations if they so choose. The ZEISS VERACITY Surgery Planner support team can assist the surgeon in reviewing their current default settings.

And remember, ZEISS VERACITY Surgery Planner is compatible with platforms outside of the ZEISS Cataract Workflow; while I personally have connected ZEISS IOLMaster 700 to ZEISS VERACITY Surgery Planner, surgeons using third-party technologies that distinctly capture K1/K2/PK1/PK2 values such as Pentacam or Cassini would still receive the benefits of seamless integration with VERACITY. Even if a surgeon opts for TK values within the calculator interface in VERACITY, the system corrects for this input imprecision. In this case, the surgeon will see their input as “TK/True K,” and can rest assured knowing that the output will be the same thanks to ZEISS VERACITY Surgery Planner selecting the most precise inputs prior to calculation. (Of course, VERACITY is customizable to each surgeon, and if a surgeon wishes to reconfigure their default settings so that the system does not override their selection, they can work with a VERACITY team member to do so. In such cases, be sure to exercise caution when reviewing calculator inputs.)

ZEISS VERACITY Surgery Planner users are all about saving time and enhancing surgical outcomes. Whether you’re a legacy VERACITY user or a recent adopter, rely on ZEISS VERACITY Surgery Planner to ensure that your data inputs maximize the elegance of modern formulas by automatically avoiding a keratometry double dip, thereby maximizing outcomes and patient satisfaction.

^{The statements of the author reflect only his personal opinions and do not necessarily reflect the opinions of any institution with whom he is affiliated.
The author has a contractual or other financial relationship with Carl Zeiss Meditec, Inc. and has received financial support.}