Eyeworld

52 | EYEWORLD | DECEMBER 2023 R EFRACTIVE LESSONS LEARNED by Liz Hillman Editorial Co-Director About the physicians Brandon Baartman, MD Vance Thompson Vision Omaha, Nebraska David R. Hardten, MD Minnesota Eye Consultants Minnetonka, Minnesota Bryan Lee, MD, JD Altos Eye Physicians Los Altos, California Dagny Zhu, MD NVISION Eye Centers Rowland Heights, California T he rotational stability of toric IOLs and reposition rates have been well stud- ied and reported. In most cases (95% according to one study 1 ), any rotation that occurs postop is usually 5 degrees off axis or less. Brandon Baartman, MD, reported a similar rate of toric rotation requiring intervention. David R. Hardten, MD, said less than 1% of his toric IOL cases need rotation. Bryan Lee, MD, JD, also reported a less than 1% return-to-OR rate for toric IOLs. "With modern lens design, it's not all that common of an occurrence that an IOL will appear to be 'off axis' postoperatively, where the lens power axis and corneal cylinder are misaligned," Dr. Baartman said. Prevention To avoid residual astigmatism in the first place, Dr. Baartman said he makes sure to use up-to- date calculators, like the Barrett Toric Calcula- tor, and Placido disc topography. "I mark the eye preoperatively to account for cyclorotation and will use an intraoperative ring (e.g., Mendez toric marker) to make sure my alignment is correct. There are a number of image guidance systems out there that do a lot of this work for surgeons, and I personally like having the ORA intraoperative aberrome- ter [Alcon] to confirm axis of astigmatism," Dr. Baartman said. Dr. Baartman said there are a few things surgeons can do to reduce the risk of in-the-bag IOL rotation postop: 1) ensure 360 degrees of overlap of the anterior capsule with the optic, 2) leave the anterior capsule unpolished, 3) remove all viscoelastic, and 4) leave the eye slightly hypotensive. He added that in long eyes (those with an axial length of more than 28 mm), surgeons can consider placing a capsular tension ring to redistribute tension and encour- age sufficient contact with the lens implant to prevent rotation. Dr. Hardten also discussed methods to ensure correct initial alignment (marking the 3 o'clock and 9 o'clock position while the patient is sitting upright, looking for a vessel, pinguecula, or other unique characteristic in the eye, and topography) and techniques to help the IOL stay where it's placed. He said to completely allow the IOL to unfold, remove all the viscoelastic (especially under the IOL), and use careful wound construction to keep the eye at physiologic pressure after surgery. Like Dr. Baartman, Dr. Hardten said he uses a capsular tension ring in larger eyes. Dr. Lee uses a digital marking system, which he noted has been shown to improve toric outcomes compared to manual marking. He also uses intraoperative aberrometry and if he is using dispersive viscoelastic, removes it from the eye and switches to cohesive prior to aberrometry. He'll then remove all the viscoelas- tic, going behind the optic with the I/A. "I gently bump the IOL against the posterior capsule before putting in intracameral antibi- otic, and I tell the patient not to squeeze as I remove the speculum and to let the OR chair do the work of sitting up," Dr. Lee said. "We ask patients to restrict bending, lifting, straining, and eye rubbing and to avoid close activities such as reading, cell phone use, and computer use for 24 hours." Toric troubles: postop rotation Toric IOL rotation procedure, from axis 108 degrees to 120 degrees Source: David R. Hardten, MD

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