EyeWorld India June 2013 Issue

25 June 2013 EWAP FEAturE Figure 1. Pentacam examination showed 0.4 D of astigmatism in the right eye in the 130-degree orientation, with pachymetry at the 8.5-mm optical zone of 580 microns. Figure 2. In the left eye, Pentacam showed 0.9 D of astigmatism at the 32-de- gree meridian centrally, yet more peripheral curvatures showed an orientation at the 48-degree meridian, which was consistent with the front elevation areas of depression. Source (all): David Hardten, MD IOL implantation followed by femtosecond arcuate relaxing incisions Post-IOL relaxing incisions benefit from femtosecond laser precision, customizability F emtosecond tarcuate relaxing incisions are often useful for patients with mild to moderate corneal toricity who would benefit from a change in the shape of their corneas. The femtosecond laser is used to create relaxing incisions in the periphery to achieve this shape change. Incisions made with a laser have several advantages over incisions made with a blade. For example, with a diamond blade, surgeons can set the blade to a certain depth, and we can control depth and location of the incision. We can also make the incision shorter or longer; however, we can’t control the angle of the entry of the blade. Additionally, surgeons really can’t see the tissue that is directly underneath the blade so it can be harder to see where we are going next in the corneal tissue. With the femtosecond laser, surgeons now have the ability to look on the screen and set the incisions exactly where they want to in relation to the pupil and the limbus. We can create incisions vertical to the corneal surface. We can angle them in or out, and we can still control things like length and optical zone or distance from the center of the pupil. This provides incisions that are more tailored or customized. Surgeons can also control depth more accurately because, as opposed to setting a diamond blade where it depends on how hard the surgeon pushes down or how hard the eye is, we now have the ability to set it to a certain number by David Hardten, MD of microns, and the incision can be created in that fashion. We can titrate the incisions to achieve the desired effect. Another advantage of femtosecond lasers is that they can be used to create intrastromal incisions, which have several benefits. For example, intrastromal incisions do not penetrate the epithelium, which minimizes the chance of infection. Case report Many patients are good candidates for this procedure. Recently, a 55-year-old man presented to my office and was interested in reducing his dependence on glasses and contact lenses. His uncorrected vision was hand motion in both eyes. His refractive error was –17.50 +2.25 x 130 in his right eye and –20.00 +2.00 x 150 in his left eye; both eyes corrected to 20/30 for distance. His exam was normal except for mild nuclear sclerosis that did not appear visually significant. He had seen a retina specialist for vitreous syneresis earlier in the year and had no high- risk retinal lesions. Pentacam (Oculus, Arlington, Wash., USA) examination showed 0.4 D of astigmatism in the right eye in the 130-degree orientation, with pachymetry at the 8.5-mm optical zone of 580 µm (Figure 1). In the left eye, Pentacam showed 0.9 D of astigmatism at the 32-degree meridian centrally, yet more peripheral curvatures showed an orientation at the 48-degree meridian, which was consistent with the front elevation areas of depression (Figure 2). The patient underwent natural lens replacement in each eye with placement of a monofocal IOL (+1.0 D in the right eye and –2.0 D in the left eye). The left eye was targeted for slight myopia. On the day of the IOL implantation, in each eye femtosecond arcuate relaxing incisions were performed with the iFS system (Abbott Medical Optics,