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Case report

Precision pulse capsulotomy complicated by radial tear of the anterior capsule: a proposed mechanism

Safuri, Shadi MD, PhD1,*; Duvdevan, Nitsan MD1; Socea, Sergiu MD1; Blumenthal, Eytan Z. MD1,2

Author Information
Journal of Cataract & Refractive Surgery: November 2019 - Volume 45 - Issue 11 - p 1680-1681
doi: 10.1016/j.jcrs.2019.07.028
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Abstract

Since the introduction of continuous curvilinear capsulorhexis in 1991,1 manual capsulorhexis remains the gold standard.1,2 Emerging technologies, such as femtosecond laser–assisted capsulotomy and precision pulsed capsulotomy (PPC),2 provide a more reproducible and precise anterior capsulotomy in regard to size, circularity, and centration. These technologies require a shorter learning curve, and might contain advantageous refractive outcomes, in particular, with toric and multifocal intraocular lenses (IOLs).3 The Zepto PPC device (Mynosys Cellular Devices, Inc.) uses a foldable disposable handpiece connected to a capsulotomy tip that is inserted through a small corneal incision. This tip consists of a soft clear silicone suction cup housing a compressible microfabricated superelastic nickel–titanium alloy (Nitinol) capsulotomy ring. After centering the ring over the anterior capsule, suction is applied to firmly attach the ring to the capsule. Thereafter, a 4-millisecond electrical waveform is applied, causing rapid phase transition of trapped water molecules and resulting in an instantaneous capsulorhexis effect that produces a free-floating circular anterior capsule flap. Several analyses, including preclinical surgical testing, Miyake-Apple imaging, thermocouple measurements, and corneal endothelial cell evaluation have demonstrated an excellent safety profile.2–5 Reports of successful clinical implementation of this technology are accumulating with no complications reported so far to our knowledge, including in challenging cases.3,4 Herein we report a case of unexpected radial tear of the anterior capsule occurring after PPC. We propose a mechanism for this complication.

Case report

A 74-year-old man, with no significant ocular history underwent phacoemulsification surgery using the Zepto PPC device for capsulorhexis. He presented with a corrected distance visual acuity of 0.3 in the operated right eye, and a 2+ nuclear cataract. The cornea was clear, no pseudoexfoliation or zonular fiber laxity was noted. A 2.6 mm clear cornea main incision was followed by intracameral anesthesia using lidocaine 1% injection and ophthalmic viscosurgical device (sodium hyaluronate 1.6%) to fill the anterior chamber. The PPC device tip was centered on the anterior capsule, then suction was applied, and air bubbles were permitted to leave the anterior chamber. Thereafter, a pulse was delivered as per manufacturer instructions. After an uneventful hydrodissection, a radial tear of the anterior capsule was apparent at the 5 o’clock position (Figure 1, C). No posterior extension of the tear or vitreous loss were noted. The surgery was continued, and a single-piece acrylic IOL was successfully implanted in the bag. At the follow-up visits (up to 1 month), the IOL remained in place with no remarkable findings. The corrected distance visual acuity was 0.8.

Figure 1
Figure 1:
(A): A snapshot from the surgery video, taken after the application of suction just before the pulse delivery. Note that an air bubble is trapped (arrow) directly under the circular wire. (B): A snapshot taken after the pulse delivery and removal of the device. Note that the capsulorhexis flap remained attached (arrow) at the precise site of the air bubble seen in A. C: Snapshot taken after the hydrodissection phase, demonstrating an anterior capsule radial tear at the precise location (arrow) of the previous trapped air bubble. D: Snapshot taken after the intraocular lens insertion, clearly demonstrating the anterior capsular radial tear.

Discussion

Initial studies of the Zepto PPC device3 demonstrate an excellent safety profile. To our knowledge, this is the first report about an unexpected radial tear complication occurring during a routine case. Upon revision of the surgery video, we were surprised to discover a small air bubble trapped precisely between the device ring and the anterior capsule that remained in place during the pulse delivery phase (Figure 1, A). Further scrutiny of the video demonstrated that the capsulorhexis flap remained attached at the site of the air bubble (Figure 1, B). This flap then tore away from the attachment point in an uncontrolled fashion, either during the hydrodissection or during the initial phacoemulsification aspiration step, leading to a radial anterior tear precisely at the site of the previously trapped air bubble (Figure 1, D). The Zepto PPC device works by instantaneous 360-degree rapid phase transition of the trapped water between the device and the capsule into vapor, resulting in a cleavage plane.5,A A trapped air bubble could interfere with the cleavage of the anterior capsule at this site, predisposing it to a residual connection point as opposed to the desired completely free-floating flap. Awareness of this potential complication and a concerted effort to ensure that no air-bubbles underlie the Nitinol wire could prevent this potential complication from occurring.

References

1. Gimbel HV, Neuhann T. Continuous curvilinear capsulorhexis. J Cataract Refract Surg 1991;17:110-111.
2. Thompson VM, Berdahl JP, Solano JM, Chang DF. Comparison of manual, femtosecond laser, and precision pulse capsulotomy edge tear strength in paired human cadaver eyes. Ophthalmology 2016;123:265-274.
3. Waltz K, Thompson VM, Quesada G. Precision pulse capsulotomy: Initial clinical experience in simple and challenging cataract surgery cases. J Cataract Refract Surg 2017;43:606-614.
4. Hooshmand J, Abell RG, Allen P, Vote BJ. Thermal capsulotomy: initial clinical experience, intraoperative performance, safety, and early postoperative outcomes of precision pulse capsulotomy technology. J Cataract Refract Surg 2018;44:355-361.
5. Chang D. Zepto precision pulse capsulotomy: a new automated and disposable capsulotomy technology. Indian J Ophthalmol 2017;65:1411.

Disclosures

None of the authors has a financial or proprietary interest in any material or method mentioned.

Other Cited Material

A. Keller BC, Sretavan D. Disruption! Inspired by Squid Suckers and Spot Welders. The definitive story of Zepto: from conception to capsulotomy. The Ophthalmologist 2016;21-27.
© 2019 by Lippincott Williams & Wilkins, Inc.