MAY 2013

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

Issue link: https://digital.eyeworld.org/i/129516

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Page 73 of 86

Update on the latest in refractive cataract techniques and technologies 3 almost " Ioperate always Placement of a toric IOL in the eye use an inkless system with a beveled marking tip that indents the epithelium. This precisely identifies the axis itself. Toric IOL choices It is great to have choices among toric IOLs. It has been well established that the one-piece acrylic design is ideal for rotational stability. Some of the distinguishing characteristics include open haptic versus plate designs. Some of the differences, in terms of optical material, are the design of the actual optichaptic junction. Asphericity, blue filtering, and other visual quality differences also distinguish some of the different torics. Remember, a variety of different toric powers are available, depending on the manufacturer. First, we select the right IOL, then we pick the specific toric correction based on the patient's needs. Implantation Toric IOL implantation is very similar to non-toric IOL implantation. However, it is important to pay at- Source: Ike Ahmed, MD tention to incision location and size. I like to keep the size down. We are moving toward 2.4-mm and 2.2-mm incisions to reduce the SIA. Also, keeping the incision farther back at the limbus rather than the anterior cornea reduces the amount of SIA. Knowing the amount of SIA is important for toric IOL calculation. One of the most important aspects of toric IOL positioning is the capsulorhexis. Ideally, the rhexis should be smaller than the IOL's optic. The IOL's haptics are designed to unfold nicely in the capsular bag. I position the toric lens within the capsular bag, inflate it with viscoelastic, rotate it into the approximate position, usually within about 10 degrees slightly under-rotated, and then let the haptics open up. Once the haptics have opened and secured themselves in the peripheral capsule at the equator, tilt the lens, remove the viscoelastic from behind the lens, let the lens come back down, and then do final maneuvering, using either the I/A handpiece, Kuglen hook, or cannula. At the conclusion of the case, keep eye pressures on a more physio- logic level, not a very high level. This promotes early adhesion of the capsule to the IOL optic and haptic material. It also allows the toric IOL to settle quicker than if the eye was overpressurized. As with any IOL, centration is important, and specifically with toric, we want to make sure the alignment is correct at the end of the case. Postoperatively, IOL rotation is rare. At the end of the day, it's about satisfying our patients and meeting expectations. We want optimal visual quality and uncorrected visual acuity, and I use that primarily as the basis for whether further treatment is required. For small amounts of residual cylinder, I will consider using an astigmatic or limbal relaxing incision. For higher amounts of residual astigmatism, especially if the lens is rotated or if the marking has been off, one may need to consider surgical intervention. Dr. Ahmed is in practice at the University of Toronto, Canada. He can be contacted at ike.ahmed@utoronto.ca. on the horizontal or the 180 degree axis. The location of the steep axis will factor into my IOL selection. "

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