Eyeworld

40 | EYEWORLD | WINTER 2025 ATARACT C About the physicians Sumit "Sam" Garg, MD EyeWorld Chief Medical Editor Vice Chair of Clinical Ophthalmology Medical Director Professor of Cataract, Corneal, and Refractive Surgery Gavin Herbert Eye Institute University of California, Irvine Irvine, California Richard S. Hoffman, MD Clinical Associate Professor of Ophthalmology Casey Eye Institute Oregon Health & Science University Drs. Fine, Hoffman, & Sims Eugene, Oregon Kevin M. Miller, MD Kolokotrones Chair in Ophthalmology Chief of the Cataract and Refractive Surgery Division Stein Eye Institute David Geffen School of Medicine at UCLA University of California, Los Angeles Los Angeles, California by Ellen Stodola Editorial Co-Director make a deep cut for the groove that follows the limbus, then you go into the groove and make a second incision plane that goes radially toward the middle of the cornea and into the eye. "The groove is 450–500 microns deep, and the sec- ond radial incision is 1.75 or 2 mm in length," Dr. Miller said. With this incision, there's a trian- gular wedge of tissue on the inner aspect of the cornea with a hinge point that acts as a valve. "If you raise the pressure in the eye, that little wedge of tissues slams against the hole and seals it off," he said. "The higher the pres- sure in the eye, the better the incision seals." In contrast, if you raise the pressure in an eye with a straight stab incision, the more you raise the pressure, the more it leaks, Dr. Miller said, adding that hinged incisions, if done properly, don't leak nearly as much. Dr. Miller also noted research from Paul Ernest, MD, on types of corneal incisions, 3 comparing which sealed best. Dr. Ernest looked at square sclerocorneal incisions, square clear corneal incisions, and rectangular clear corneal incisions. "He found that square incisions in the cornea sealed best," Dr. Miller said. So, if you have a squared incision and hinge it, you'll have a good corneal incision that seals well, Dr. Miller said. "If you place that incision appropriately, you can also reduce the astigma- tism of the eye accordingly." Richard S. Hoffman, MD, chooses to make his cataract incision at the temporal location. "A small temporal clear corneal incision induc- es little if any astigmatism and will not cause long-term against-the-rule drift such as can occur with a superiorly placed incision," he said. "Some surgeons will place their incision on the steep axis in order to help reduce cylinder, but I have found it more reliable to place the incision at 180 degrees and address astigmatism management with limbal relaxing incisions or toric IOLs." He also reiterated that most cataract inci- sions today are clear corneal. "The sclera can also be utilized in patients who have corneal pathology that might make a corneal incision problematic," Dr. Hoffman said. The clear corneal incision can be made as a single planar entry or a two-plane incision made within a limbal grooved incision. Incisions in cataract surgery W hen considering cataract surgery, one of the most basic steps is choosing the incision to be used. Several physicians discussed the impact of these incisions, sizing considerations, and important techniques and principles to ensure a successful surgery. To take out a cataract, you have to make an incision, said Kevin M. Miller, MD. "Back in the old days, we didn't make corneal incisions; we made scleral incisions because we didn't have foldable lenses." While modern-day corneal incisions come with the downside of needing to make a cut into the eye, a key benefit is they are small and can also help modify pre-existing cor- neal astigmatism. "We can use the architecture and placement of an incision to mitigate some of the eye's astigmatism," he said. "I think it's a very pertinent topic for sur- geons to understand the impact of how your incision can impact the surgically induced astigmatism," said Sumit "Sam" Garg, MD, noting a paper 1 from Jack Holladay, MD, about induced astigmatism and the impact of incision location and size. "What he showed is that for most incisions placed at zero, meaning at the horizontal axis temporal, they have very little astigmatic effect with respect to the centroid er- ror." As a result, Dr. Garg said he places most of his incisions here. "I'm trying to be astigmatical- ly neutral because in many of my patients, I'm treating astigmatism concomitantly," he said. Factors like the width of the incision and the placement can impact the potential astigmatic effect of the incision. If you make the incision closer to the visual axis, you'll have more of an astigmatic effect. Dr. Miller explained that the simplest incision is like a straight stab into the eye with a keratome blade. You can use this single-plane incision or a multi-plane incision. "The most common is a two-plane incision," he said. "You make a groove, straight down at the limbus, and go inside the groove about halfway down to make the radial portion of the incision." Using a femtosecond laser, multi-plane incisions can be done up to three planes. He discussed incision types, noting the hinged incision concept from David Langer- man, MD. 2 It's a two-plane incision where you

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