Eyeworld

57 Supported by unrestricted educational grants from Alcon Laboratories and Omeros Reducing ultrasound energy during cataract surgery helps reduce postoperative inflammation S urgical stress during cata- ract surgery triggers a cas- cade of metabolic events that result in inflamma- tion. However, by examining the surgical factors that contribute to inflammation, we can develop strategies to minimally disrupt other tissues and prevent heat damage. Increased stress Postoperative corneal edema is associated with ultrasound time and irrigation/aspiration (I/A) volume during the procedure, as well as the cataract density. Surgical techniques such as the stop and chop technique result in greater phaco time, power, and effec- tive phacoemulsification time (EPT) compared with the nuclear pre-slice technique. Divide and conquer requires more time and uses more energy than chopping techniques. Viscoelastics also play a role in this process. Exothermic viscosurgi- cal devices increase heat production more than cohesive viscoelastics. During surgery, we need to avoid manipulation. Incisional trau- ma, epithelial trauma, and endothe- lial cell loss cause surgical stress. The surgical difficulties we encounter, such as a dense nucleus, broken cap- sules, retained nucleus or cortex, iris turbulence and trauma, and other challenges, also increase stress by lengthening our procedures. Furthermore, if we are not care- ful, foreign substances such as intra- cameral antibiotics, generic forms of Impact of ultrasound energy during refractive cataract surgery by Mitchell A. Jackson, MD Figure 1. In FLACS, the femtosecond laser creates the capsulotomy, entry wounds, and astigmatic incisions and performs lens fragmentation. Figure 2. Dr. Jackson's procedure for femtosecond laser-treated lens removal Mitchell A. Jackson, MD trypan blue, povidone iodine, and intravitreal preparations can increase the inflammatory response. Gentler surgery Advances in phacoemulsification technology and surgical techniques are reducing surgical stress. Phaco technology now delivers ultrasound in smaller pulses of en- ergy—resulting in less tissue trauma and inflammation. Femtosecond lasers perform several functions in cataract surgery and precisely target laser energy to pre-fragment or soften the lens (Figure 1). Femtosecond laser-assisted cata- ract surgery (FLACS) and ultrasound phacoemulsification use cavitation to disrupt tissue. However, the laser delivers energy more efficiently, with less heat and less collateral damage Procedure Catalys (AMO) Femto LDV Z6 (Ziemer) LENSAR (LENSAR) LenSx (Alcon) Victus (B+L) Anterior capsulotomy X X X X Lens fragmentation X X X X Corneal incisions X X X X X Arcuate incisions X X X X X The newest systems are highly automated and extremely precise, replacing the manual requirement for 3 of 5 steps (capsulotomy, fragmentation, corneal incisions). My femtosecond laser-treated lens removal • Aspiration of nucleus fragments • Efficient vacuum aspiration • Dual-linear control of power and vacuum • Minimal to no post-occlusion surge • Microburst (more energy efficient) • 26–28% ultrasound power • 1–75% duty cycle (waveforms per cycle) • 8 ms burst duration • Waveform – 60% depth • Cortex removal • Precise vacuum control • Single-use silicone irrigation/aspiration handpiece Simultaneous dual-linear control of aspiration and ultrasound enables fine-tuned optimization for post femtosecond cataract surgery continued on page 58

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