EyeWorld Asia-Pacific September 2018 Issue

55 EWAP DEVICES September 2018 Views from Asia-Paci c Brendan VOTE, MD Launceston Eye Institute 36 Thistle St. West, South Launceston, Tasmania 7249, Australia Tel. no. +61-(0)438648574 eye.vote@me.com T he development of new technology and the prospect of advances in surgical techniques and outcomes is exciting. This article enthusiastically highlights the Zepto capsulotomy system designed to create uniform 5.2-mm capsulotomies utilizing a disposable handpiece. Through a “suction, energy, and release” process Zepto delivers patented microbubble phase effect tissue cutting, where a thin layer of water molecules trapped between a nitinol capsulotomy ring and lens capsule undergoes rapid (4 ms) phase transition. The resulting volume expansion instantaneously cuts all 360˚ of the capsule. 1 “ ...healthy skepticism is required when assessing new technologies, ensuring our enthusiasm is based on sound scientific evidence. ” - Brendan Vote, MD Nonetheless, healthy skepticism is required when assessing new technologies, ensuring our enthusiasm is based on sound scientific evidence. With enthusiastic skepticism we undertook an independent analysis of the Zepto device. Our first study 2 of 100 consecutive eyes found complete free-floating capsulotomy was only achieved in 70 eyes (72%). Focal attachments were identified in 17 eyes (18%) and broad attachments in 10 eyes (10%). Additionally, intended Zepto capsulotomy failed in 3 eyes due to operator/device error. Concerningly, anterior capsule tears occurred in 4 eyes (4%). Statistical analysis of complications indicated no evidence of a learning curve effect—suggesting complications more likely linked to the underlying device than surgeon factors. Concurrent investigation of the ultrastructural features 3 confirmed irregularities at the capsule margin in some of the capsulotomy specimens (see Figure), consistent with the frayed edges seen clinically at slit-lamp postoperatively. We postulated inconsistent distribution of electrical energy through the nitinol cutting element. This was investigated and confirmed by the manufacturer, resulting in device modification and algorithm changes. A follow-up series 4 of 50 consecutive patients with the updated handpiece highlighted significantly improved complete capsulotomies (96%); however, the radial tear rate remained unacceptably high (4%). We postulate this might be explained by “asymmetric tensile effects of suction acting on the anterior capsule” generated during the manually (third party) controlled “ release ” mechanism. Device failure in 2 cases (4%) also continued to be an issue. In conclusion, the Zepto capsulotomy system is exciting technology in evolution. It certainly offers the ability to create consistent (reproducible) “ideal” sized (5.2 mm) strong (when intact) capsulotomies. However, there remain concerns over radial tears and device failure which have as a potential factor the third party (non-surgeon controlled) operator. Finally, we found at current cost of around US$150/device, Zepto is not cost-effective 1 and would need to be significantly cheaper to be affordably incorporated into operating theater costs. References 1. Keller C, et al. Re: Ultrastructural integrity of human capsulotomies created by a thermal device. Ophthalmol. 2018 (in press). 2. Hooshmand J, et al. Thermal capsulotomy: Initial clinical experience, intraoperative performance, safety, and early postoperative outcomes of precision pulse capsulotomy technology. J Cataract Refract Surg . 2018 Mar;44(3):355-361. 3. Hooshmand J, et al. Ultrastructural Integrity of Human Capsulotomies Created by a Thermal Device. Ophthalmol . 2018 Mar;125(3):340-344. 4. Hooshmand J, et al. Intraoperative performance and Ultrastructural integrity of human capsulotomies created by the improved precision pulse capsulotomy device. J Cataract Refract Surg . 2018 (in press). Editors’ note: Dr. Vote declared no relevant financial interests. continued on page 56