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EW San Diego 2015 6 " For many patients, a toric IOL is going to be the best option for visual rehabilitation. Adding toric IOLs to your surgical armamentarium is the most effective way to enter refractive cataract surgery. " Eric Donnenfeld, MD what special steps do you take to be certain the viscoelastic is removed appropriately? Dr. Vukich: Your management of re- tained viscoelastic at the conclusion of the case is important. You need to be sure the lens doesn't rest on a bed of viscoelastic. You want some appositional touch of the posterior surface of the lens to the posterior capsule, which helps to lock it in place. Going beneath the lens with the I/A tip often moves the lens slightly. I prefer to tap the anteri- or surface of the lens to dislodge trapped viscoelastic. Dr. Garg: With venturi fluidics you don't necessarily have to go behind the lens if you don't need to, so tapping the lens works well. Dr. Hovanesian: I always obtain the best removal by going behind the lens with the I/A tip and flushing it out. This is important because retained viscoelastic can cause vaulting or tilting of any IOL and irregular outcomes. Dr. Donnenfeld: How do you check your final alignment before ending the case? Dr. Garg: Before we had the Callisto Eye, I marked the cornea after using the intraoperative aberrometer to know where I wanted to leave the lens. Dr. Donnenfeld: What is your sur- gical technique to ensure the best chance of proper lens alignment? Dr. Garg: The capsulorhexis should be small enough so that it covers the edge of the optic 360 degrees. I leave the lens 10–15 degrees short of where I want to it to finally rest. Using my I/A probe, I remove the viscoelastic. Using my viscoelastic cannula or I/A probe, I rotate the lens into position (Figures 5–8). Dr. Vukich: I've become more con- scious of the potential error induced by parallax. We're marking the cor- nea but rotating the lens in the cap- sular bag, and you can have a 2-mm or 3-mm difference between your marking at the periphery and the actual marks on the lens. If you're looking at it at an angle, it's possible to introduce error. If you're working with topical anesthesia, direct the patient to look into the center of the microscope, which will help elimi- nate parallax. If you're using a block, manually make sure the eye looks as on-axis as possible. Sources of error and postoperative management Dr. Donnenfeld: In the 2014 ASCRS Clinical Survey, more than 30% of respondents believed 10 degrees of postoperative rotational error does not have a significant effect on visual quality in a normal toric IOL patient. What are your thoughts? Dr. Mah: With each diopter you lose about 3% of your correction, so with 10 degrees you lose about one-third of your correction. Dr. Kontos: As you increase the cylindrical power of the lens, the cylinder correction and axis place- ment are even less forgiving, so it is important for surgeons to under- stand that 10 degrees is too great an error. Dr. Donnenfeld: When you see a patient postoperatively and a lens is not in the right location, what is the most common reason and how do you manage this problem? Dr. Hovanesian: Guy Kezirian, MD, once told me that almost 5% of toric lenses are implanted 90 degrees off axis in the United States. Usually this happens because of confusion between the steep and the flat axis. More common is an error in placing the lens or marking by a few de- grees. When it exceeds that, postop- erative rotation may have occurred. Dr. Donnenfeld: In most cases I've seen, the toric IOL was placed in the wrong position. However, lenses are unstable in very high myopes and large eyes with large capsular bags. I sometimes use a capsule tension ring in these patients. If the lens is in the wrong position, I generally reposition it. Dr. Garg: When rotating the lens postoperatively, it's important that Figure 5. Leave the toric IOL about 15 degrees shy of target orientation prior to removal of viscoelastic. Figure 6. If needed, go behind the IOL to remove any residual viscoelastic. It is very important to ensure complete removal of viscoelastic in toric IOL cases.

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