Eyeworld

28 | EYEWORLD | NOVEMBER 2019 ATARACT C DEVICE FOCUS "As the capsule opening gets smaller you are less likely to catch the edge of the optic on the edge of the anterior capsular rim and that's a good thing, but if you get too far below 5 mm—and with the laser you could make these exactly the size you wanted—we learned that it continued from page 26 Measurement is key to obtain an ideal capsulorhexis. This image demonstrates forceps which have built-in measurement capabilities for that purpose. Mark is 2.5mm from tip (radius) Mark is 5.0 mm from tip (diameter) The capsulorhexis overlaps the edge of the optic for 360 degrees but is large enough so that it does not cover a significant part of the optic. Source(all): Uday Devgan, MD Purkinje images are aligned in the central visual axis Edge of capsulorhexis overlaps the optic for 360 o started getting progressively more difficult to operate due to such a small opening." For extremely dense cataracts, Dr. Patter- son creates a 6.5–7-mm capsulorhexis. "With really rock hard lenses, you need more room to maneuver, and with these very large openings there is no overlap at all," Dr. Patterson said. Lens positioning impact The capsulorhexis plays a role in determining the final resting place of the optic—known as the effective lens position —when accounting for IOL calculations, Dr. Devgan said. "If most of the optic is overlapped by the capsulorhexis, even if it is less than the full 360 degrees, the effective lens position will likely be stable," Dr. Patterson said. "[If] you are look- ing at the white-to-white and the center of the limbus and the iris, you will see it centered in such a way that when you insert the implant [it] will be in its final resting place and it's going to overlap." Pearls for a manual capsulorhexis Pearls for a good capsulorhexis, Dr. Patterson said, include filling the anterior chamber with viscoelastic to the point of pushing the lens back and flattening the anterior lens surface. Instead of starting a capsulorhexis with a tear using forceps, Dr. Patterson uses a bent needle to minimize viscoelastic loss. "It's just easy and quick and cheap, and you just put it in underneath the capsule and just keep going. And you've just got to take your time and don't let it extend too far out, but if you do, then there are techniques to pull it back in," Dr. Patterson said. For Dr. Devgan, ensuring precise measure- ment for an ideal capsulorhexis means using forceps, which have these measurements built in. "This allows for exact planning for every case and it just takes a second or two," Dr. Devgan said. "Many forceps come with these tips and you can even add these marks to your existing forceps."

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