Eyeworld

EW FEATURE 70 IOL calculations February 2015 by Vanessa Caceres EyeWorld Contributing Writer Intraoperative aberrometry helps steer surgical outcomes Clinic, Cleveland. The technology across platforms works particularly well for patients with previous laser surgery and for patients who require a toric IOL, he said. It also is espe- cially useful in eyes that are longer or shorter than usual, Dr. Ianchulev said. In a study of 246 eyes published last year in Ophthalmology and led by Dr. Ianchulev, there was more than a 50% increase in accuracy with use of the device in eyes with previous myopic LASIK or photorefractive keratectomy compared against the surgeon's best preop choice, the Haigis L formula, and the Shammas IOL formula. 1 Francisco, and chief medical officer, Transcend Medical, Menlo Park, Calif. "This is then used to derive precise IOL power." Dr. Ianchulev holds 4 patents for intraoperative aberrometry related to the ORA system (Alcon, Fort Worth, Texas). In the United States currently, the ORA system and the HOLOS IntraOp (Clarity Medical Systems, Pleasanton, Calif.) are approved for use. There are other systems avail- able outside the U.S. This article will focus on pearls for using these devices. Specific in- formation about each system will be featured in future issues of EyeWorld. The devices continue to evolve and become more accurate, said Shamik Bafna, MD, Cleveland Eye While the technology has a learning curve, pearls can assist in overcoming those challenges M ore cataract surgeons are turning to intraop- erative aberrometry to help identify a precise IOL power for patients. Yet how does the technology work, and what variables can affect outcomes? EyeWorld asked some experts in the field for answers. "The devices are made from the idea of measuring the eye while we are operating to gather refractive in- formation to help make decisions," said Robert Weinstock, MD, The Eye Institute of West Florida, Largo, Fla. "The raw data translates into a prescription after it's taken through different formulas," said Jonathan Solomon, MD, Solomon Eye Physicians & Surgeons, Bowie, Md. "It guides refinement in hopes of achieving a better outcome refrac- tively." "Intraoperative aberrometry works by using a Talbot-Moire waveform aberrometer to measure the optical powers of the eye at the time of surgery, such as aphakic and pseudophakic, as well as astigmatic residuals," said Sean Ianchulev, MD, MPH, clinical associate pro- fessor, University of California, San Monthly Pulse Keeping a Pulse on Ophthalmology T he topic of this Monthly Pulse survey was "IOL calculations." We asked, "Which generation IOL formula do you routinely use for normal eyes?" More than half of respondents use 3rd generation formulas (Holladay 1, Hoffer Q, SRK/T). The majority of respondents rely on the ASCRS Post-Refractive IOL Calculator to determine the IOL power for post-refractive eyes. Regarding posterior corneal astigmatism, when choosing the toric power, most respondents said they don't have a way to measure it so they do not make any adjustments. Finally, we asked about long eyes >25 mm. The majority uses the correction factor formula for axial lengths then calculates with the new length. The was followed closely by the response "Use the SRK/T formula without any modifications." AT A GLANCE • Intraoperative aberrometry is helping to improve cataract surgery outcomes, particularly in patients with previous laser refractive surgery or those receiving a toric IOL. • The technology has a learning curve; surgeons should monitor IOP, the tear film, and patient positioning during its use. • Surgeons should always have a backup plan in place and check intraoperative aberrometry's results against their preop readings. The technology evolution

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