Hiroyo Kurosaka

Fibrous membrane formation at the capsular margin in capsule contraction syndrome.

PURPOSE To determine whether the pathogenesis of capsule contraction syndrome involves the outgrowth of the fibrous membrane from the anterior capsule margin. SETTING Department of Ophthalmology, Keio University School of Medicine, Tokyo, and the Ando Eye Clinic, Kanagawa, Japan. METHODS A retrospective review of medical records and slitlamp photographs was conducted in 12 eyes (10 patients) that had required treatment for a narrowed anterior capsule opening after cataract surgery. All patients had had continuous curvilinear capsulorhexis and phacoemulsification with implantation of an intraocular lens in the capsular bag. Specimens of surgically removed fibrous membrane were examined by histopathological methods. RESULTS Fibrous membrane on the inner surface of the anterior capsule and the linear folds of the anterior capsule were present in each eye. In 10 eyes of 8 patients, the fibrous membrane was on the outer surface of the anterior capsule and covered the capsular folds at its margin. Pathological study showed that this fibrous membrane consisted of the flattened lens epithelial cells that proliferated on the inner and outer surfaces of the shrunken anterior capsule. The outgrowth of this membrane from the margin of the anterior capsule to the center of the opening of the anterior capsule was noted. CONCLUSION In this study, capsule contraction syndrome involved contraction of the fibrous membrane as well as its outgrowth from the capsule margin.

Inhibition of Lens Epithelial Cell Migration by an Acrylic Intraocular Lens in vitro

We developed a new in vitro system to evaluate the effect of intraocular lenses (IOLs) on the migration of lens epithelial cells (LECs) and determined how acrylic and other IOLs influence LEC migration using this model. In an in vitro system, porcine LECs were cultured in a cell culture chamber insert, containing a collagen membrane, for 10 days with no IOL or with various types of IOLs. Migration of LECs beneath each IOL optic was observed with an inverted-phase microscope. The cell-free areas under the IOL optic, where the LECs had not migrated, were measured. Without IOL, LECs completely covered the collagen membrane within 5 days after plating (5.0 ± 0.0 days). Complete coverage was slowed by a silicone IOL (6.7 ± 1.2 days, p = 0.0305). LECs cultured with acrylic or with round- or sharp-edged polymethylmethacrylate (PMMA) IOLs did not completely cover the area. Ten days after initiating cultures, the cell-free areas under IOLs with sharp edges (acrylic, 41.1 ± 8.0%; sharp-edged PMMA, 60.9 ± 39.0%) were significantly larger than under IOLs with round edges (silicone, 0.0 ± 0.0%; round-edged PMMA, 1.5 ± 1.2%). A sharp edge may act as a barrier to LEC migration. Moreover, LEC migration under the acrylic IOL slowed after the LECs had crossed the barrier of the optic edge, perhaps due to acrylic adhesive properties. Only a few LECs reached the collagen membrane beneath the central 3 mm of the acrylic IOL. This new in vitro model was useful in evaluating the effect of various IOLs on LEC migration. Acrylic IOLs inhibited LEC migration by not only a sharp edge but also other factors, such as adhesive properties.

Elschnig pearl formation along the neodymium: YAG laser posterior capsulotomy margin: Long-term follow-up

Purpose: To examine the long‐term occurrence and course of Elschnig pearl (string of pearls) formation along neodymium:YAG (Nd:YAG) laser posterior capsulotomy margins. Setting: Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan. Methods: The clinical records of eyes having an Nd:YAG posterior capsulotomy to treat posterior capsule opacification after cataract surgery were retrospectively reviewed. Kaplan‐Meier and Cox proportional hazards analysis were performed. Results: Among 201 eyes, string of pearls developed in 139 (69.2%). The mean follow‐up after the Nd:YAG posterior capsulotomy was 32.1 months ± 25.3 (SD). At 2 years, the cumulative probability of developing string of pearls was 77.0% (95% confidence interval [CI], 70.6%‐83.4%), after which it reached a plateau. Among the 139 eyes, 100 had sufficient data to be reviewed to assess the long‐term outcome (mean follow‐up from Nd:YAG posterior capsulotomy, 43.7 ± 26.0 months). A second Nd:YAG posterior capsulotomy was performed in 18 eyes (18.0%) to treat progression of string of pearls, typically within 2 years after the initial Nd:YAG capsulotomy. The string of pearls disappeared spontaneously in 31 eyes (31.0%). The probability of disappearance was 80.4% (95% CI, 63.4%‐97.4%) 8 years after the Nd:YAG posterior capsulotomy. Cox proportional hazards analysis identified no factor significantly favoring the disappearance of the string of pearls. Conclusions: String of pearls was a common complication after Nd:YAG laser posterior capsulotomy. About 20% of cases were progressive and required a second capsulotomy; however, most regressed over several years.

Effect of Posterior Convexity of Intraocular Lenses on Lens Epithelial Cell Migration

PURPOSE To investigate in vitro how the posterior convexity of an intraocular lens (IOL) affected the migration of lens epithelial cells (LECs) under its optic. METHODS Porcine LECs were cultured for 9 days with polymethylmethacrylate (PMMA) IOLs in a cell culture chamber insert containing a collagen membrane on which the IOLs were implanted. The central sagittal optic depths of the implanted IOLs were 0, 0.158, 0.303, and 0.452 mm. The migration of LECs was observed with an inverted phase microscope. The cell-free area under the IOL optic, where LECs had not migrated, was measured. RESULTS As time elapsed, LECs migrated onto the collagen membrane beneath the IOL optics from the periphery to the central area in a concentric fashion in all IOL configurations. At 5 days in culture, the greater central sagittal optic depths of the IOL optic were associated with wider cell-free areas (P=.0108). At 9 days in culture, LECs almost completely covered the collagen membrane under IOLs with 0-, 0.158- and 0.303-mm central sagittal optic depth whereas the cell-free area under the 0.452-mm IOL was 4.3+/-3.0% (P=.0029). CONCLUSIONS The posterior convexity of an IOL optic has an inhibitory effect on LEC migration under the optic. However, this inhibition had little effect after 9 days in culture.

Extracellular Matrix Influences Proliferation of Cultured Porcine Lens Epithelial Cells

Purpose: To investigate whether extracellular matrix (ECM) influences the proliferation of cultured lens epithelial cells (LECs). Material and Methods: Porcine LECs were cultured in F-12 nutrient mixture supplemented with 5% fetal bovine serum (FBS) for 24 or 96 hours on the dishes coated with laminin, fibronectin, type I collagen, or type IV collagen. As a control, LECs were cultured on uncoated dishes. Twenty-four or ninety-six hours later, the number of cells was determined. We determined the proliferation ratio of the number of cells 96 hours after plating to the number of cells 24 hours after plating. This ratio was used to assess the cell proliferation. Results: The ratio of the LECs on the uncoated dishes was 2.3. Dish coating with type I or type IV collagen, and fibronectin significantly increased this ratio (4.0, 3.5, and 3.0, respectively), whereas coating with laminin did not affect this ratio (2.5). Conclusion: These findings suggest that ECM influences cultured porcine LEC proliferation. (J Jpn Ophthalmol Soc 103:432–435, 1999)

Effect of Rabbit Aqueous Humor Obtained after Cataract Surgery on Collagen Gel Contraction Induced by Bovine Lens Epithelial Cells

We evaluated the effect of specimens of pre- and postoperative aqueous humor on the contraction of collagen gels, and the effect of transforming growth factor-β2 (TGF-β2) in postoperative aqueous humor. Rabbit aqueous humor was collected preoperatively and on postoperative day 7. Bovine lens epithelial cells (LECs) were cultured in collagen gel in F-12 nutrient mixture supplemented with 5% fetal bovine serum that contained 10% aqueous humor obtained under various conditions. Gel area was determined on day 4. Gels cultured with the medium that contained phosphate-buffered saline showed a statistically significant contraction after 4 days. Aqueous humor from aphakic or pseudophakic eyes significantly increased contraction, with both specimens having a similar effect. Approximately 60% of the contractile effect of the postoperative aqueous humor was neutralized by anti-TGF-β2 antibody. However, the promoting effect of the aqueous humor sampled postoperatively was less than that sampled preoperatively. Although the aqueous humor obtained postoperatively increased the contractility of the LECs, with the level of TGF-β2 apparently responsible for much of its effect, the effect was less than that observed in the aqueous humor obtained preoperatively.