Capsular Equator Research Articles

Capsule Dynamics, Implantation, and Explantation of the Smaller Incision, New-Generation Implantable Miniature Telescope: a Miyake-Apple Study.

The smaller incision, new-generation implantable miniature telescope is a novel implant to optimize vision in retinal patients with central vision loss. Using Miyake-Apple techniques we visualized the device implantation, repositioning, and explantation, while noting capsular bag dynamics. Using the Miyake-Apple technique, we assessed capsular bag deformation after successful implantation of the device in human autopsy eyes. We assessed rescue strategies for converting a sulcus implantation to a capsular implantation and explantation strategies. We noted the occurrence of posterior capsule striae, zonular stress, and the haptics' arc of contact with the capsular bag after implantation. Acceptable zonular stress was observed during the successful implantation of the SING IMT. When it was implanted in the sulcus, one could reposition the haptics into the bag with two spatulas using counter-pressure in an effective strategy despite inducing tolerable, medium zonular stress. A similar technique, in reverse, allows safe explantation without damaging the rhexis or the bag, while inducing similar medium, tolerable zonular stress. In all eyes we examined, the implant considerably stretches the bag, inducing a capsular bag deformation and posterior capsule striae. The SING IMT can be safely implanted without significant zonular stress. In sulcus implantation and explantation, repositioning of the haptic is achievable without perturbing zonular stress using the presented approaches. It stretches average-sized capsular bags to support its weight. This is achieved by an increased arc of contact of the haptics with the capsular equator.

An Experimental Laboratory Study Using the Miyake-Apple Posterior View Technique to Investigate the Dynamics Between Capsular Bags and Different IOL Models.

To evaluate the dynamics between capsular bags and different intraocular lens (IOL) models in human cadaver eyes using the Miyake-Apple posterior view technique. In an in vitro laboratory study, human cadaver eyes were prepared according to the Miyake-Apple posterior view technique. Five IOLs from each of the six groups (Avansee 1P [Simonvision], Avansee 3P [Simonvision], CT Lucia [Carl Zeiss Meditec], Acrysof [Alcon Laboratories, Inc], RayOne [Rayner], and CT Asphina [Carl Zeiss Meditec]) were implanted into capsular bags with different diameters. The empty capsular bag diameter and capsular bag diameter with an IOL in it were evaluated based on the Miyake-Apple view pictures. Posterior capsule striae were observed and compared between groups. The arc of contact between IOLs and the capsular equator was noted. Correlations between the empty capsular bag diameter and the capsular bag diameter with IOL, as well as between the empty capsular bag diameter and the arc of contact, were examined. With the Avansee 3P as a reference, the area deviation of the haptics of IOL models with looped haptics was compared. The capsular bag diameter with IOL inside and the arc of contact were proportional to the empty capsular bag diameter. The RayOne, Avansee 3P, and CT Lucia showed a longer arc of contact. Posterior capsule striae were observed in the Avansee 1P (1, 20%), Avansee 3P (5, 100%), Acrysof (1, 20%), and RayOne (2, 40%). Areas of deviation were 0.38 mm2 (Avansee 1P), 0.24 mm2 (CT Lucia), 0.34 mm2 (Acrysof), and 0.31 mm2 (RayOne), respectively. Different IOL models showed varied characteristics in terms of capsular bag fitting and arc of contact. Understanding these dynamics is critical to optimizing postoperative outcomes. [J Refract Surg. 2022;38(10):654-660.].

How to Manage the Cortex After CTR Insertion.

Capsular tension ring (CTR) realizes safe cataract surgery. However, residual cortex removal becomes difficult with CTR. Originally, the flushing technique was developed for intracameral antibiotic administration. Using this technique with larger amounts of solution enables surgeons to 1) deliver antibiotics to the anterior chamber and area behind the intraocular lens, resulting in stable, scheduled antibiotic concentration and 2) entirely irrigate and displace the area, leading to the effective cleansing of residual substances and bacterial pollution. When performing the flushing technique, the residual cortex and debris that were not eliminated by ordinary irrigation and aspiration can be pushed out to the anterior chamber. Applying flushing technique to CTR cases, the residual cortex and debris trapped between the CTR loop and capsular equator is lifted into the anterior chamber and easily removed. If the capsular bag is polluted by bacteria, it may also be lifted to the anterior chamber.

The study of different sizes and shapes of CCC (Continuous Curvilinear Capsulorhexis) in mature cataracts with & without trypan blue

The study of different sizes and shapes of CCC (Continuous Curvilinear Capsulorhexis) in mature cataracts with & without trypan blue - IJCEO- Print ISSN No: - 2395-1443 Online ISSN No:- 2395-1451 Article DOI No:- 10.18231/j.ijceo.2019.075, Indian Journal of Clinical and Experimental Ophthalmology-Indian J Clin Exp Opht

Prevention of posterior capsule opacification by adenovirus-mediated herpes simplex virus thymidine kinase/ganciclovir system

Background There is no effective preventing way for the posterior capsular opacification(PCO) after cataract surgery.Objective The aim of this study was to investigate the preventing effect of adenovirus-mediated herpes simplex virus thymidine kinase/ganciclovir(HSV-tk/GCV) system on PCO.Methods Twelve New Zealand white rabbits were divided into BSS+BSS group,BSS+GCV group,HSV-tk+BSS group and HSV-tk+GCV group at random.Phacoemulsification was performed in bilateral eyes of rabbits,and 0.1ml of BSS or adenovirus vector with HSV-tk gene were injected into lens capsular bag during the operation based on the grouping.In 12 hours after operation,0.1ml BSS was injected into the anterior chamber daily for 3 times in BSS+BSS group and HSV-tk+BSS group,and 0.1ml GCV was used in the same way in BSS+GCV group and HSV-tk+GCV group.The situations of the anterior segment and the posterior capsule were examined under the slit lamp postoperatively.All the wet weight of capsular bags was assessed using electronic balance.The capsular membrane was histopathologically examined in the 4th week after injection.PCO was graded according to the method of Couderc.Results Mild corneal edema and aqueous humor opacity were observed in all the eyes within 3 days and returned to normal level gradually within 2 weeks postoperatively.PCO scores were higher in BSS+BSS group,BSS+GCV group,HSV-tk+BSS group than the HSV-tk+GCV group,showing the significant differences between them(H=2.647,P=0.008;H=2.939,P=0.003;H=2.884,P=0.004).No obvious difference was seen in PCO score among BSS+BSS group,BSS+GCV group,HSV-tk+BSS group(P＞0.05).The wet weight of the capsular bags in HSV-tk+GCV group was reduced in comparison with BSS+BSS group,BSS+GCV group,HSV-tk+BSS group with the statistically significant difference between them(q=9.93,q=10.15,q=10.07,P＜0.05).Histopathological examination revealed that mild proliferation of lens epithelial cells(LECs) at the capsular equator and migration toward the posterior capsule to form a thin soemmering ring in the periphery of the capsular bags and thin fibromembrane at the center of the capsular bags without cells or cortices in HSV-tk+GCV group.However,in BSS+BSS group,BSS+GCV group and HSV-tk+BSS group,the proliferation and migration of LECs were more obvious to form a dense soemmering ring in the periphery of the capsular bags and thick fibromembrane in the center of capsular bags.Conclusion Adenovirus-mediated HSV-tk/GCV system can effectively prevent PCO. Key words: Adenovirus vector; Thymidine kinase; Ganciclovir; Lens; Posterior capsule opacification

Capsular stabilization device to preserve lens capsule integrity during phacoemulsification with a weak zonule

We describe a new capsular stabilization device for suspending a lens with weak zonular support. It is flexible, 10.0 mm in length, and fashioned from 5-0 nylon. The contact portion is bent at 1.25 mm with an end bifurcating to form a T-shape to minimize stress on the capsular equator. After a continuous curvilinear capsulorhexis is created, the capsular stabilization devices to hook the capsulotomy margin are inserted. The T-shaped end is passed around the anterior capsular flap to fit the curvature of the equator. Phacoemulsification and aspiration using this device was performed in 12 eyes of 9 patients, and the usefulness and complications were analyzed. The capsular stabilization devices suspended the capsule and facilitated safe phacoemulsification in all eyes. Posterior capsule rupture occurred in 2 eyes. None of the cases had notable postoperative complications. This device ensures a stable capsule-iris complex and reduces surgical risks.

Experimental studies of capsular equator rings of soft latex

Purpose To determine the efficacy of wide equatorial rings of various materials in reducing posterior capsule opacification (PCO) and maintaining the circular contour of the capsular equator in a rabbit model. Setting Laboratory for Intraocular Microsurgery and Implants, Goldschleger Eye Research Institute, Tel-Aviv University, Sheba Medical Center, Tel-Hashomer, Israel. Methods Closed rings made of poly(methyl methacrylate), Teflon®, polyurethane, and latex were introduced into the capsular bags of rabbit eyes after removal of the lens material. The soft latex rings were deemed the only practical rings for atraumatic implantation through a small incision. Latex rings of 2 dimensions with rectangular edges were implanted in 8 rabbits. One eye served as a control after lens removal and no ring implantation. The eyes were followed for up to 5 months and then evaluated by light microscopy. Results Posterior capsule opacification was minimal or absent in all animals implanted with the latex rings. Mild to moderate inflammatory reaction was noted in most eyes. It was caused by the ring material or secondary to long-standing pressure on the ciliary tissue. The rings also maintained well the circular contour of the capsular bags. Conclusions Equatorial rings of soft latex with sharp rectangular edges were effective in minimizing PCO and maintaining the shape of the capsule after lens removal in rabbits. Soft rings made of a biocompatible material may be effective in humans.

Ideal size of an intraocular lens for capsular bag fixation

Purpose: To determine the ideal size of an intraocular lens (IOL) for proper capsular bag fixation in different sizes of evacuated capsular bags.Setting: Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea, and Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.Methods: Fifteen eyes obtained post-mortem were divided by crystalline lens size into three groups. Intraocular lenses of five different sizes were implanted in each capsular bag. The arc of contact between the haptics and capsular equator and the capsular bag distortion with each IOL were measured and compared using posterior-view analysis.Results: The arc of contact was directly proportional to the IOL size and inversely related to the lens size. The smallest arc of contact was 2.0 mm with the smallest IOL implanted in the largest lens group. The maximum capsular bag distortion was 2.6 mm in the case of the largest IOL implantation in the smallest lens group.Conclusion: Implanting an IOL smaller than 12.5 mm in a large capsular bag can result in unstable fixation, while implanting an IOL larger than 12.5 mm in a small capsular bag can result in excessive stretching and distortion of the capsular bag and surrounding zonules.

Experimental study of different intraocular lens designs implanted in the bag after capsulorhexis

Objective: To analyze experimentally in cadaver eyes several models of commercially available posterior chamber intraocular lenses (IOLs) to determine their stability, fixation, and behavior in the capsular bag in relation to their overall size, optic diameter, shape, material, and haptic configuration.Setting: Eye Bank and Department of Ophthalmology, University General Hospital of Alicante, Spain.Methods: Thirty-three IOLs of different sizes, shapes, and designs, divided in two series and five groups, were implanted successively in 31 cadaver eyes. All the proceedings were videotaped, and measurements were made on the television screen with the picture static. Main outcome measures were the diameters of the lens, the empty capsular bag, and the capsulorhexis; capsular distension by the IOL haptics; extent of haptic arc of contact with the capsular equator; and IOL mobility in the bag.Results: The stability of and stretching caused by the IOLs varied greatly depending on their overall size, haptic flexibility, and the extent of the arc of haptic contact with the capsular equator. Lenses between 13.5 and 14.0 mm had good stability but stretched the capsule excessively. The J-loop haptic configuration produced a spindle-shaped bag deformity that might come in contact with the ciliary processes in the physiologic eye. Among IOLs designed for in-the-bag implantation after capsulorhexis, the two smaller than 12.0 mm were unstable, permitting excessive mobility in the capsular bag. Except for IOLs with a 5.0 mm optic, all 12.0 mm IOLs had reasonable stability, little or no mobility within the capsular bag, and good short-term centering. Lenses with a broad angulation at the haptic-optic junction, to about 90 degrees, achieved the largest arc of contact with the equator and behaved as lenses with larger optics. The Pharmacia 808 performed best.Conclusion: After capsulorhexis and extracapsular cataract extraction, 12.0 mm, poly(methyl methacrylate), one-piece IOLs with modified C-shaped loops, 90 degree angulation at the haptic-optic junction, and an optic diameter between 6.0 and 6.5 mm performed best in the capsular bag.

The Capsular Bag after Short- and Long-term Fixation of Intraocular Lenses

To investigate the effect of posterior chamber intraocular lens (PC IOL) size and construction on the capsular bag in human cadaver eyes. Studies were done at two timeframes: (1) short term (prospective)--the effect of 12 different IOLs on the capsular bag configuration after experimental implantation; and (2) long term--(retrospective) analysis of eyes with PC IOLs obtained post-morterm. The short-term study showed the maximal diameter of the capsular bag to be 11.0 mm for IOLs with total diameter of 12.0 mm and 11.5 mm for 13.5- to 14.0-mm IOLs. Longer IOLs caused more ovaling of the bag with stress lines (striae) on the posterior capsule. Secondary processes such as proliferation of epithelial cells (Soemmering ring) and capsular fibrosis caused the capsular bag to resume a more circular shape with irregular contour. The area of contact between the IOL loops and the capsular equator was significantly lower in eyes with radial tears and IOLs with the J-loop design compared with the C-loop design. In both the short- and long-term groups, maximal capsular diameter did not exceed 12.0 mm. The results of this study suggest that using the capsulorrhexis technique, a 12.0-mm total diameter IOL is sufficient to provide stable capsular fixation.

Spontane Luxation einer Silikon-Disc-Linse 4 Monate post operationem in den Glaskörper

We report on a patient who experienced an acute deterioration in visual acuity at night four months after implantation of a silicon-disc lens into the capsular bag. On examination, the artificial lens was localized preretinally. The capsular equator was fibrous, but had retained its circular shape. The posterior capsule was ruptured. The rupture may be explained by tension in the posterior capsule, which is only 1-4 microns thick, within the shrunken capsular bag, and by an acute increase of intraocular pressure caused by rubbing of the eyes during sleep.

Analysis of capsular bag defects and intraocular lens positions for consistent centration

Radial anterior capsular tears frequently occur in posterior-chamber iris-plane phacoemulsification cases. These tears extend to the capsular bag equator and can allow the knee of an in-the-bag posterior chamber intraocular lens (IOL) to unfold a smaller anterior capsular remnant. This unfolding can allow the knee of the IOL loop to extend beyond the capsular equator, leading to IOL decentration. Typical anterior capsular radial tear configurations along with guidelines for IOL design selection and orientation after recognition of these tears are presented. Proper IOL centration was achieved in 255 of 262 patients (97%) in a study observing these guidelines.