Evaluation of Lens Capsule Stability Using Capsular Tension Ring, Iris Retractor, and Capsule Expander Using a Porcine Model With Zonular Dehiscence

Abstract

Citation: Yaguchi S, Yaguchi S, Bissen-Miyajima H. Evaluation of lens capsule stability using capsular tension ring, iris retractor, and capsule expander using a porcine model with zonular dehiscence. Invest Ophthalmol Vis Sci. 2019;60:3507-3513. https:// doi.org/10.1167/iovs.19-27449PURPOSE. We evaluate the efficacy of capsular tension rings (CTRs), iris retractors (IRs), and capsule expanders (CEs) in stabilizing the lens capsule under different degrees of zonular dehiscence using a porcine model. METHODS.We developed an experimental model that can be used to observe the dynamics of lens capsules with different degrees of zonular dehiscence during phacoemulsification and aspiration (PEA). PEA was performed without any aid (control) and with devices. A CTR was used for a dehiscence of 308, 458, 608, 908, 1208, 1508, and 1808 and one to four IRs or one to three CEs were used for a dehiscence of 908, 1208, and 1808. The retention rate, calculated as the area of the capsular bag during PEA divided by the area before zonular dissection, and the number of lens fragments dropped into the vitreous cavity during PEA were examined and compared among the control and experimental groups. RESULTS.The retention rate increased significantly with the use of devices compared to the control (P < 0.05). The number of dropped lens fragments decreased by one or less with the use of CTR, one IR, or one CE for 908, two IRs, or one or two CEs for 1208, and three or four IRs, or two or three CEs for 1808 of zonular dehiscence. CONCLUSIONS.The experimental porcine eye model with zonular dehiscence makes it possible to observe the entire configuration of the lens capsule, and demonstrates differences in the efficacy of capsular bag retention with CTR, IR, and CE.

Evaluation of the Utility of Capsular Stabilization Devices in a Zonular Fiber Defect Model with the Slit Side View System

“…Yaguchi et al demonstrated that use of the experimental porcine eye model with zonular dehiscence allows observation of the entire configuration of the lens capsule, and they also demonstrated differences in the efficacy of capsular bag retention with a CTR and CE [ 17 ]. In our current study, we demonstrated that with SSV, we were able to observe the intraoperative lens, the anterior chamber dynamics, and the three-dimensional movement of the capsular bag in the zonular fiber defect model.…”

Efficacy of Femtosecond Laser-Assisted Capsulotomy: Experimental Evaluation Using the Zonular Dehiscence Model

“…The eye model of ZD was first created under the operating microscope using the technique that we previously reported in both porcine and human eyes. 6,7 The anterior chamber was filled with an ophthalmic viscosurgical device (OVD; Provisc; Alcon Vision, LLC, Fort Worth, TX); the entire iris root and the planned range of the ZD were dissected using capsule diathermy (CD-1000, Tagawa Electronic Research Institute, Chiba, Japan).…”

“…We created a unique porcine eye model of ZD to observe the lens capsule and the crystalline lens during phacoemulsification 6,7 and adapted this eye model for the current study. Our primary and secondary objectives, respectively, were to observe the relationship between the quality of the capsulotomy and the range of ZD in porcine eyes and confirm the effectiveness of FL-assisted capsulotomy in human cadaver eyes with ZD.…”

Changes to the Anterior Capsular Opening of Human Lens after Cataract Surgery in Patients with Subluxated Lenses. Summary of the Doctoral Thesis

“…In experimental study with artificially induced varying grade zonular defects in pigs eyes, using iris retractors and CTR during surgery for stabilisation of the capsular bag, convincing statistically significant maintenance of the capsular bag's form was established compared with the control group, as well as statistically significant reduced entry of lens core fragments in the vitreous body (Yaguchi et al, 2019). The capsule's tension ring was implanted in most cases prior to phacoemulsification, so that the contour of the capsular bag of the subluxated lens was maintained during surgery, providing a function as a barrier between the eye's anterior and posterior segment and reducing the risk of tearing of the remaining zonule (Cionni & Osher, 1998;Cionni et al, 2003;Georgopoulos et al, 2007;Gimbel et al, 1997;Vasavada et al, 2012a).…”

“…Even though the phacoemulsification method does not differ in the sense of visual acuity and postoperative complications from other contemporary lens subluxation surgery methods (for example, pars plana lentectomy with scleral fixation of the intraocular lens (IOL)) (Thapa et al, 2016), it does include several advantages within itmore surgeons (cataract surgery) are familiar with the method, there is more phacoemulsification equipment, a shorter period for learning the method, simpler additional instruments and auxiliary devices (capsular and iris hooks, capsular tension rings (CTR) and segments), the use of which is consequently easier to learn, a shorter surgery time (Thapa et al, 2016), as well as lower surgical costs compared to other methods. The introduction of additional instruments and auxiliary devices should also be noted, starting from capsular tension rings which appeared in 1991 (Hara et al, 1991;Nagamoto & Bissen-Miyajima, 1994) until their evolution into the CTR concept which is used nowadays (Legler et al, 1993), design variations in 2007 (Henderson Ring) (Henderson & Kim, 2007), application of the modified CTR (Cionni Ring and mCTR) from 1998 (Cionni & Osher, 1998), improvement of the design associated with Malyugin in 2012 (Malyugin B, 2012), use of the iris retractors in lens subluxation surgery from 1997 (Novak, 1997) and its gradual development in subsequent decades (Yaguchi et al, 2011(Yaguchi et al, , 2019.…”