Welcome to LRIcalc.com, the only place to access the Wörtz-Gupta® Formula calculator for femtosecond laser arcuate incisions. This formula has been validated through an unsponsored peer reviewed publication in Clinical Ophthalmology. The full text article can be accessed for free here.
The goal of this calculator is to provide surgeons with a tool to estimate the arc length and location of corneal arcuate incisions made by the femtosecond laser for the correction of low corneal astigmatism (below 1.25D). It is important to note that this formula has been derived using anterior keratometry only, and it is recommended anterior Ks be used for the input. The cataract incision is dictated to be placed at 0 or 180 (temporally) in all cases. The arcuate incisions will always be placed on the steep access. The formula has a standard SIA built in, and is designed to offset against-the-rule posterior corneal astigmatism. It is also designed for a 9.0mm optical zone (4.5mm radius), and 80% depth.
While other nomograms were designed to be used with manual instruments to debulk higher amounts of astigmatism, this formula has been designed with the precision of the femtosecond laser in mind, and does not attempt to advise for correcting astigmatism in the range that toric IOLs can be a better option. With that in mind, the maximum arcuate incision length recommended by the calculator is 50 degrees, to prevent unwanted irregular results.
Please use this as a guidance tool among many, along with your best judgment, to treat your patients.