Deeper understanding of toric IOL calculations can help avoid postoperative errors

At the Hawaiian Eye meeting earlier this year, I presented a case in which a patient who underwent cataract surgery with a toric IOL had residual astigmatism postoperatively, even though the IOL was perfectly positioned at the intended axis. One of my mentors, Jack Holladay, MD, MSEE, FACS, explained to me that the error was likely in the toric calculation and that the HICSOAP software — Holladay IOL Consultant & Surgical Outcomes Assessment Program, www.hicsoap.com — would help pinpoint the issue.The first step was to double check all data from the preoperative measurements. The patient had consistent corneal power readings from three different devices, including topography, tomography and automated keratometry. The data were entered correctly, without any transcription errors, into the manufacturer’s online toric calculator. On the day of surgery, the patient’s cardinal meridians were correctly marked and the IOL was precisely placed at the correct axis.