EyeWorld Asia-Pacific September 2018 Issue

56 EWAP DEVICES September 2018 Surgeons can use the resulting visual landmark during surgery to align the IOL within the capsul- otomy. Other advantages Surgeons using the device have identified another, unintended benefit, Dr. Sretavan said. In the last step where suction is reversed, ophthalmic viscosurgical device is reintroduced along with a little balanced salt solution and creates a subcapsular fluid wave. Surgeons have reported this helps hydrodissection and also seems to remove lens epithelial cells under the capsule that they otherwise need to remove using other meth- ods. “Zepto appears to be more than just a capsulotomy device; it appears to also help in other steps of surgery such as hydrodissection and cortical cleanup,” Dr. Sretavan said. Dr. Chang’s research on the device has found the simultaneous use of suction seems to create a microscopic curling of the cut cap- sulotomy edge that imparts greater tear resistance. 1 “Unlike with the femtosecond laser, there is no cutting or dis- turbance of the underlying cortex because only tissue in contact with the thin nitinol edge will be cut,” Dr. Chang said. “Therefore, hydro- dissection and cortical removal are no different than with a manual capsulorhexis.” Zepto’s manufacturing protocols aim to avoid nitinol capsulotomy rings with imperfections (top left) and procedure only rings that enable 360-degree even energy delivery (top right); a Zepto capsulotomy with 360-degree, slightly rolled-up, and strong capsulotomy edge from cadaver eye (bottom left); surgi- cal photo showing Zepto capsulotomy after lens phaco and cleanup (bottom right). Source: David Sretavan, MD The strength of the capsul- otomy edge is important with more complicated cases. Dr. Chang’s and others’ research comparing Zepto to manual and femtosecond laser capsulotomy found it was consist- ently stronger in paired human cadaver eyes. 2 “It is with large, brunescent cataracts that we exert the most surgical force on the capsular bag and capsulorhexis,” Dr. Chang said. “For example, with chopping we have to manually separate the two hemi-nuclei much further apart to fracture the posterior nu- clear plate.” Pearls identified Surgeons have identified a variety of ways to improve the device’s performance. “Initial experience has taught us the importance of retracting the push rod all the way back to its starting position before activating suction,” Dr. Chang said. “Other- wise, insufficient suction could cre- ate a skip area in the cut, and this was a part of my learning curve.” Among the pearls Dr. Yeu has found to improve efficiency with the device is extending wounds from the 2.2 mm required to 2.3 mm, which eases ingress and egress of the Zepto device. Dr. Waltz has found it unnec- essary to use capsular dye once a surgeon becomes comfortable with Zepto. “If you have a dense cataract and you are afraid of an anterior capsular rip, Zepto makes a precise 360 degree cut, so you release the pressure in a real way,” Dr. Waltz said. “You can also put the Zepto behind a small pupil, and you can get a good 5.2-mm capsulotomy behind the pupil.” EWAP References 1. Chang DF, et al. Precision pulse capsulotomy: Preclinical safety and performance of a new capsu- lotomy technology. Ophthalmol. 2016;123:255–64. 2. Thompson VM, et al. Compari- son of manual, femtosecond laser, and precision pulse capsulotomy edge tear strength in paired hu- man cadaver eyes. Ophthalmol. 2016;123:265–74. Editors’ note: Dr. Sretavan, Dr. Chang, and Dr. Waltz have financial interests with Mynosys. Dr. Yeu has no financial interests related to her comments. Contact information Chang: dceye@earthlink.net Sretavan: sretavan@mynosys.com Waltz: kwaltz56@gmail.com Yeu: eyeu@vec2020.com Reports of early – from page 55