Capsule Opacification

Abstract: Purpose: To determine whether posterior capsule opacification (PCO) is influenced by intraocular lens (IOL) material. Setting: A British teaching hospital eye department. Methods: Ninety eyes were prospectively randomized to receive a poly(methyl methacrylate) (PMMA), silicone, or AcrySof® IOL. All lenses had 6,0 mm optics and PMMA haptics. A standardized surgical protocol was performed by a single surgeon using an extracapsular technique with capsulorhexis. Patients having surgical complications were excluded, and all patients had standardized medication and follow-up. Posterior capsule opacification was assessed by a digital retroillumination camera using a dedicated software program based on the analysis of texture in the image and calculated as the percentage area of opacified capsule. Data were analyzed 2 years postoperatively. Results: There was a significant difference in percentage of PCO at 2 years among the three lens types (P < .0001). The AcrySof lenses were associated with less PCO (median 11.75%) than PMMA (43.65%) and silicone (33.50%) lenses (P < .001 and P = .025, respectively). The difference between PMMA and silicone lenses was not statistically significant. Conclusion: Intraocular lenses made from AcrySof were associated with a significantly reduced degree of PCO.

Abstract: Purpose: To clarify which factor—intraocular lens (IOL) design or material—contributes most to the inhibition of migrating lens epithelial cells (LECs). Setting: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. Methods: After phacoemulsification, an acrylic IOL with sharp optic edges wasimplanted in 1 eye and a poly(methyl methacrylate) (PMMA) IOL with an optic design similar to that of the acrylic IOL in the contralateral eye of 4 rabbits. Results: The Miyake view and histopathological findings 3 weeks after surgeryrevealed that the lens capsule wrapped tightly around the optic edges, conforming to a distinctly sharp rectangular bend there with both IOL types in all rabbits. The migrating LECs were inhibited at the site, and a massive Soemmering's ring cataract was formed. Conclusions: The discontinuous sharp capsule bend created by the sharp optic edges in both IOL types appeared to induce contact inhibition of the migrating LECs. The preventive effect of an acrylic IOL on posterior capsule opacification may be design dependent.

Abstract: Originally, the open poly(methyl methacrylate) (PMMA) capsular tension ring (CTR) was designed to compensate for zonular defects or to stretch the posterior capsule in highly myopic eyes not receiving an intraocular lens (IOL). We address the variety of subsequent designs, applications, and techniques that have evolved. With pre-existing or intraoperative zonular defects, a standard CTR may be inserted before or at any time during cataract removal to maintain or re-establish an extended capsular diaphragm. For profound zonular dialysis or weakness, a CTR was designed for scleral fixation. Capsular tension rings with integrated tinted sector shields have been developed to compensate for sector iris colobomas or aniridia. The CTR has also been used as a measuring gauge for in vivo quantification of capsule dimensions and postoperative capsular shrinkage. The CTR has improved control during primary posterior capsulorhexis and prevented oval distortion along the lens axis postoperatively. During combined cataract and vitreous surgery, a CTR prevents capsule damage and provides undisturbed peripheral visualization before IOL implantation. Capsular tension rings may also influence capsule opacification formation. A special band-shaped CTR with sharp edges was developed to inhibit lens epithelial cell migration and avoid capsulorhexis-optic contact.