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6 S everal options exist today for managing astigmatism in cataract surgery. Among the surgical options are toric intraocular lenses, cataract incision placement, laser vision correction, corneal/limbal relaxing incisions, and intrastromal femtosecond keratotomy. The latter of these is also the newest. There are several important advantages to performing intrastromal astigmatic keratotomy (ISAK), but in my opinion one of the more significant is that the epithelium remains intact since the femtosecond incision starts just under Bowman's. No break in the epithelium may decrease post-op discomfort, reduce the likelihood of dry eye symptoms, and reduce the chance of infection. It's a quick procedure with fast visual recovery. We know that astigmatism can affect uncorrected vision, and with today's demanding patients we cannot neglect its correction when we're planning for either cataract or refractive lens exchange surgery. In a retrospective analysis of 1,182 normal eyes of presbyopic patients where the sphere was within 0.25 D of zero, it comes as no surprise that higher rates of astigmatism were correlated with worse uncorrected visual acuity (see Figure 1). Whether we opt to use limbal relaxing incisions, corneal incisions, or astigmatic keratotomy, it's basi- cally the same concept—precisely cutting corneal lamellar induces a flattening in that meridian. The goal of any of these surgical proce- dures is to improve unaided vision and reduce patients' dependence on spectacle or contact lens correction. The newer femtosecond lasers recently introduced for cataract surgery are able to perform this type of astigmatism correction. That may also be viewed as a disadvantage, since it entails an additional cost for the practice. However, many practices already have access to femtosecond lasers used for the LASIK procedure, such as the IntraLase (Abbott Medical Optics, AMO, Santa Ana, Calif.). We recently evaluated the safety and efficacy of ISAK using the iFS Advanced Femtosecond Laser (AMO) in patients with residual astigmatism after they underwent a cataract/ refractive lens exchange procedure. A total of 93 patients (110 eyes) were treated with ISAK at Optical Express centers in the U.K. by Jan Venter, M.D., and other surgeons. The average patient age was 58 years with a range between 44 and 69 years. There were more males than females treated (63% vs. 37%, respectively) and slightly more right eyes (57%) than left. EW Chicago 2012 6 Laser vision correction by Steve Schallhorn, M.D. Intrastromal astigmatic keratotomy offers substantial advantages Steve Schallhorn, M.D. " We know that astigmatism can affect uncorrected vision, and with today's demand- ing patients we cannot neglect its correction when we're planning for either cataract or refractive lens exchange surgery " Maximizing results by minimizing post-op cylinder Before ISAK procedure Mean sphere: +0.58 D (±0.38), ranging from –0.75 D to +2.25 D Cylinder: –1.28 D (±0.59 D), ranging from –3.5 D to –0.5 D Manifest refractive spherical error: –0.06 D (±0.42), ranging from –1.50 D to +0.88 D At month 1 (79 eyes) Mean sphere: +0.22 D (±0.48), ranging from –1.50 D to +1.50 D Cylinder: –0.71 D (±0.66 D), ranging from –3.00 D to 0.00 D Manifest refractive spherical error: –0.13 D (±0.49), ranging from –1.88 D to +0.88 D At month 3 (54 eyes) Mean sphere: +0.29 D (±0.50), ranging from –1.00 D to +1.50 D Cylinder: –0.60 D (±0.53 D), ranging from –2.75 D to 0.00 D Manifest refractive spherical error: –0.02 D (±0.44), ranging from –1.38 D to +1.25 D AMO Saturday supplement_Chicago 2012-USE THIS ONE_Layout 1 4/20/12 4:25 PM Page 6

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