Yoshiharu Yamada

Effect of indomethacin-coated posterior chamber intraocular lenses on postoperative inflammation and posterior capsule opacification

Abstract We implanted indomethacin‐coated intraocular lenses (IOLs) in rabbit eyes to ascertain how the sustained release of the drug affects postoperative inflammation and posterior capsule opacification (PCO). A preoperative resolution test showed that 1 % indomethacin‐coated IOLs placed in balanced salt solution released a mean 14.0 ± 0.6 µg of the drug within 24 hours. Postoperatively, aqueous flare intensity in eyes with 0.1% indomethacin‐coated IOLs and in eyes with 1.0% indomethacin‐coated IOLs was significantly less at day 2 and at days 2 and 3, respectively, than in control eyes with uncoated lenses. In another group of eyes, histopathological examination showed that those with 1.0% indomethacin‐coated lenses had significantly less PCO than the contralateral control eyes with uncoated IOLs.

Explantation of endocapsular posterior chamber lens after spontaneous posterior dislocation

Abstract The management of spontaneous posterior dislocation of an intraocular lens (IOL) (11.0 mm in overall diameter) encapsulated within the remaining lens capsule is presented. The patient was a 55‐year‐old man who had had phacoemulsification following continuous curvilinear capsulotomy for monocular cataract 3 years earlier. The dislocated, encapsulated IOL was lifted up by hooking the fibrotic capsular opening with a bent disposable needle following vitrectomy and then explanted. A conventional posterior chamber lens with modified C‐loops was inserted and sutured in the ciliary sulcus. This technique may be an alternative treatment for a posteriorly dislocated IOL. Histopathological examination clearly revealed that lens epithelial cell migration stopped at the planoconvex optic edge. This finding may be consistent with reports that the incidence of posterior capsule opacification with the planoconvex IOL is lower than with the biconvex IOL.

Complications associated with endocapsular balloon implantation in rabbit eyes

Abstract After phacoemulsifying the lens in six rabbit eyes through a 1.3 mm anterior capsule opening, we implanted a silicone balloon in the capsular bag and filled it with liquid silicone. The eyes were enucleated nine to 21 months postoperatively, embedded in paraffin, stained with toluidine blue, and examined by stereoscopic and light microscopy. We looked at the postoperative complications primarily. All balloons were securely fixated within the capsule. Surface wrinkles were observed in two balloons. The injected silicone remained transparent. None of the lens capsules was completely transparent, although all remained relatively clear. Retrocorneal membranes were produced in one eye in which the silicone leaked.

Capsule opacification after refilling the capsule with an inflatable endocapsular balloon

Purpose: To describe the features of capsule opacification in rabbits and cynomolgus monkeys after the capsules were refilled with an inflatable endocapsular balloon. Setting: Nishi Eye Hospital, Jinshikai Medical Foundation, Osaka, Japan. Method: Capsule opacification was evaluated by slitlamp examination, Miyake view, and histopathological examination in 15 eyes of 15 rabbits and 16 eyes of 13 primates from 4 to 32 months after the lens capsule had been refilled. Results: The incidence of capsule opacification was 94%. In the eyes that did not have lens epithelial cell (LEC) removal, a monolayer of LECs was seen on the posterior capsule when the lens capsule was tautly refilled, whereas a thick layer was seen when the lens capsule was moderately or poorly refilled. In the eyes that had LEC removal, the opacification was generally less marked regardless of the amount of refilling. In two rabbit capsules that were refilled moderately or tautly and had LEC removal, the capsule remained clear. Neodymium:YAG capsulotomy in two eyes did not cause herniation of the injected silicone. Conclusions: Filling the capsule tautly and removing the LECs effectively reduced capsule opacification but could not completely inhibit LEC migration. This suggests the need for more efficient and thorough LEC removal or even a pharmaceutical approach to prevent capsule opacification after lens refilling.

Accommodation in Primate Eyes After Implantation of Refilled Endocapsular Balloon

PURPOSE To restore accommodation after crystalline lens removal. METHODS The crystalline lens of one eye of each of four primates was removed by phacoemulsification. Each operated-on eye underwent endocapsular silicone balloon implantation followed by filling with an organosilicone mixture. Seven months postoperatively, the anterior chamber depth and refractive power changes were measured before and after topical application of 4% pilocarpine. RESULTS In the refilled eyes, the average anterior chamber depth reduction was 0.50 mm and the average maximal myopic change was 6.74 diopters. CONCLUSION After lens removal, measurable accommodation was restored in the eyes with the endocapsular balloon filled with an organosilicone mixture.

Comparison of shape recovery ratios in various intraocular lens haptics.

ABSTRACT Since understanding the mechanical properties of intraocular lens (IOL) haptic materials can minimize decentration after surgery, we have examined shape recovery ratios of various intraocular lens haptics (polypropylene [PP], polyvinylidene fluoride [PVDF], extruded poly(methyl methacrylate) [PMMA]) currently on the market under conditions that approximate clinical use. The results using various Ascon lens‐holding forceps and compression tests, during which the lenses were held in a cylindrical holder for seven days, one month, and three months, indicated that PVDF haptics had better shape recovery capability than PP and extruded three‐piece PMMA haptics.

Comparison of shape recovery ratios of single-piece poly(methyl methacrylate) intraocular lens haptics

We studied shape recovery ratios of several single- and three-piece intraocular lens (IOL) haptics after conducting compression tests for various lengths of time. Results of the comparison of poly(methyl methacrylate) (PMMA) IOL haptics configured of a single piece and of three pieces showed a superior shape recovery ratio for single-piece haptics. Comparisons of the shape recovery ratios among single-piece PMMA haptics and conventional three-piece haptics made of polyvinylidene fluoride (PVDF), PMMA, and polypropylene (PP) revealed that the shape recovery ratio of single-piece PMMA haptics was higher than the ratios of the conventional three-piece PMMA and PP haptics. The ratios of two of three of the single-piece PMMA haptics, however, were lower than the ratios of three-piece PVDF haptics. The form and manufacturing procedures of haptics likely have a significant impact on the shape recovery ratio of haptics, even those made of the same material. Since decentration after IOL surgery could be caused by the condition of the patients lenticular capsule and Zinns zonule, it is difficult to conclude that the shape recovery ratio is the only factor in IOL stability. Nevertheless, this study indicates that IOL haptics that cause less decentration and have better mechanical properties should be developed.

Decreased prostaglandin E2 synthesis by lens epithelial cells cultured on heparin-surface-modified poly(methyl methacrylate)

Purpose: To evaluate whether heparin surface modification reduces prostaglandin E2 (PGE2) synthesis by lens epithelial cells (LECs) after intraocular lens (IOL) implantation. Setting: Nishi Eye Hospital, Jinshikai Medical Foundation, Osaka, Japan. Methods: The prostaglandin E2 (PGE2) concentration was determined in an incubation medium of human cataract LECs cultured on heparin‐surface‐modified (HSM) poly(methyl methacrylate) (PMMA) plates at 1, 2, 3, and 4 weeks of culture. A medium without heparin served as a control. Results: The PGE2 concentration was significantly lower in the HSM than in the control medium at 3 and 4 weeks of culture. Conclusion: The results are consistent with the clinical observation of significantly decreased inflammation in eyes with HSM IOLs, indicating that such modification increases PMMA’s biocompatibility with LECs. J Cataract Refract Surg 1996, 22:859‐862