CataraCt Surgery aStigmatiC CorreCtion

By Eric D. DonnEnfElD, MD Astigmatic management is the step that most often keeps patients from achieving optimal visual quality after refractive cataract surgery. Residual astigmatism of 0.50 D and sometimes less may result in glare, symptomatic blur, ghosting, and halos. A recent study of 4,540 eyes of 2,415 patients showed that corneal astigmatism was present in the majority of patients undergoing cataract surgery, with at least 1.50 D measured in 22.2% of study eyes.1 Approximately 38% of eyes undergoing cataract surgery have at least 1.00 D of preexisting corneal astigmatism, and 72% of patients have 0.50 D or more.2 The use of manual limbal relaxing incisions (LRIs), although moderately effective, has been an art form with inherent variability in its predictability. LRIs require expertise and entail some risk, and they simply are not performed by the great majority of ophthalmic surgeons. For these reasons, the need for a technology that improves the safety and effectiveness of corneal relaxing incisions is great. Femtosecond lasers increase precision by creating reproducible incisions at the desired optical zone, depth, and length, all of which should make incisional treatment more of a science and less of an art.3 In a study of initial results with the LenSx Laser (Alcon), 8-mm arcuate incisions reduced astigmatism by 70%.4 When performing laser arcuate incisions, surgeons must first determine their length, their depth, the steep axis of corneal cylinder, and the distance from the visual axis. I employ a 33% reduction of the Donnenfeld nomogram (Figure 1) in conjunction with the LRI calculator Correcting Corneal astigmatism With Laser incisions