ATARACT SURGICAL INSTRUMENTS
Latest Advances in Cataract Surgery
Experts Tell All by Tan Sher Lynn
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t the recent annual meeting of the American Society of Cataract and Refractive Surgery (ASCRS 2020), which was held virtually on May 16 to 17, the latest advances in cataract surgery were among the hot topics discussed — in particular, surgical systems, instruments and devices. Below are some of the experts’ takes on these innovations.
Reducing occlusion break surge in cataract surgery Occlusion break surge during phacoemulsification (PKE) cataract surgery can lead to potential surgical complications. According to Dr. Kevin M. Miller from the David Geffen School of Medicine at UCLA in Los Angeles, USA, anterior chamber stability during cataract surgery is essential for patient safety and occlusion break surge risks this stability. Surge volume factors include PKE system (hardware), operating settings (software), and eye compliance. In an experimental study, he and his colleagues characterized post-occlusion break surge volume (SV) with the Centurion Active Sentry peristaltic system (CAS; Alcon Inc., Geneva, Switzerland); Whitestar Signature Pro peristaltic system (WSP; Johnson & Johnson Vision, Jacksonville, Florida, USA); and Stellaris PC venturi system (SPC; Bausch + Lomb, Quebec, Canada), under varying intraocular pressures (IOP), vacuum limits (Vac), and aspiration rates (Asp).
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To provide surgical measurements, a mechanical eye model that mimics the compliance of the human eye was used to imitate the anterior chamber volume-pressure change behavior. Using this model, the SV of the systems was characterized at a Vac of 300 to 650mmHg, IOP of 30 to 80mmHg, and Asp of 20 and 40cc/min (the SPC does not have an Asp setting). “We found that SV is heavily dependent on the phaco system used and its surgical settings,” shared Dr. Miller. “CAS had a significantly lower surge volume at all surgical settings compared to WSP and SPC. CAS also had the highest level of case-to-case consistency compared to WSP and SPC,” he further explained.
Effects of torsional power during PKE Meanwhile, Dr. Santaro Noguchi from Saneikai Tsukazaki Hospital in Japan examined how torsional amplitude, sleeve type, tip type and IOP settings affect the intraocular perfusion supply. He found that the infusion rate during PKE is greatly affected by torsional power (TP). Using the Centurion Vision System (Alcon), the weight of BSS (balanced saline solution) Plus 500 (0.0184%) injected during torsional PKE was measured. He discovered that except for the balanced tip+ultra sleeve setting, all perfusion flow tended to decrease due to the influence of TP. In particular, in the case of TP with 80% or more, the decrease of perfusion
| June/July 2020
rate was remarkable. Dr. Noguchi concluded that the anterior chamber is likely to become unstable in cases requiring high TP, and suggested the use of the ultra sleeve especially for hard nuclei, and that it is better to raise IOP only when TP is high.
Maximum visual outcomes, minimum iatrogenic effects The goal of modern cataract surgery is to produce excellent visual outcomes while minimizing iatrogenic effects and improving procedural efficiency. Dr. David M. Lubeck and colleagues performed a systematic literature review (SLR) to evaluate recent clinical evidence comparing safety, efficacy and efficiency of different PKE systems. They searched through PubMed and EMBASE/MEDLINE databases to compare clinical efficacy and safety data for the Centurion Vision System versus other PKE systems. From 6,132 records, they identified 27 relevant articles and extracted data from eight articles comparing the Centurion and Infiniti Vision Systems (Alcon). “While the Centurion Vision System maintains the excellent safety profile established by the Infiniti Vision System, results show that the Centurion
