Toshiyuki Nagamoto

A ring to support the capsular bag after continuous curvilinear capsulorhexis.

Abstract We designed four prototypes of a capsular bag supporting ring for supporting and preserving postoperative integrity of the capsular bag, independently of the intraocular lens (IOL) implanted following continuous curvilinear capsulorhexis. An open poly(methyl methacrylate) ring, inserted experimentally in cadaver eyes through a 3.5 mm incision, adjusted well to various capsular bag sizes and could be implanted with common IOL types. Although some capsular shrinkage occurred in vitro, the roundness of the capsular bag equator was preserved, suggesting that the ring may help maintain postoperative capsular bag integrity.

Comparative Study of Intraocular Lens Implantation Through 3.2- and 5.5-mm Incisions

PURPOSEnTo prospectively and comprehensively compare the clinical results of two small-incision cataract surgery procedures, silicone intraocular lens (refractive index of 1.46) implantation through a 3.2-mm incision and polymethylmethacrylate intraocular lens implantation through a 5.5-mm incision.nnnMETHODSnTwo hundred eyes with cataract randomly were assigned to either procedure. Except for incision size, identical surgical methods were used in every case. Data on uncorrected and corrected visual acuity, keratometry, corneal topography, flare-cell measurement, fluorophotometry, specular microscopy, glare disability measurement, and photographic examination of intraocular lens decentration were analyzed up to 6 months after surgery.nnnRESULTSnEyes in the 3.2-mm incision group displayed significantly better uncorrected and corrected visual acuity in the early postoperative period, lower aqueous flare intensity and cell counts immediately after surgery, less operatively induced astigmatism throughout the study period, and less corneal topographic changes taken 3 months after surgery. No significant between-group differences were noted for other parameters. Complications in the two groups were few and comparable.nnnCONCLUSIONnBoth procedures of small-incision cataract surgery offered satisfactory clinical results, but 3.2-mm incision cataract surgery allowed significantly earlier recovery of visual function and better preservation of corneal shape.

Effect of intraocular lens design on posterior capsule opacification after continuous curvilinear capsulorhexis

Abstract We compared the effect of biconvex and convex‐piano (posterior piano) intraocular lenses on posterior capsule opacification (PCO) following continuous curvilinear capsulorhexis (CCC) in 212 eyes. During the three years following surgery, the cumulative frequency of neodymium:YAG laser posterior capsulotomy, calculated with the Kaplan‐Meier method, was significantly higher in patients in the biconvex group (32.5% by the third year) than in those in the convex‐piano group (5.9% by the third year) (P < .05, Wilcoxon’s test; P < .01, Cox‐Mantel’s test). Measured with the tracing method, the area within a 5 mm diameter central circle that developed Elschnig pearls was 2.93 ± 4.91 mm2 in the biconvex group and 1.66 ± 2.37 mm2 in the convex‐piano group. In the study, PCO was less severe in the convex‐piano group than in the biconvex group following CCC. These results are contrary to those reported previously in patients with can‐opener capsulotomy.

Three year prospective, randomized evaluation of intraocular lens implantation through 3.2 and 5.5 mm incisions

Purpose: To compare the long‐term clinical results of two small incision cataract surgery procedures. Setting: Seven centers in Japan. Methods: Two hundred eyes were randomly assigned to receive a silicone intraocular lens (IOL) through a 3.2 mm incision or a poly(methyl methacrylate) (PMMA) IOL through a 5.5 mm incision. Except for incision size and implantation technique, the surgical methods were identical. Uncorrected and corrected visual acuity, keratometry, flare‐cell intensity, specular microscopy, and neodymium:YAG (Nd:YAG) laser posterior capsulotomy rate were analyzed up to 3 years after surgery. Results: Eyes in the 3.2 mm incision group had significantly better uncorrected and corrected visual acuity in the early postoperative period and lower aqueous flare intensity immediately after surgery, but these differences disappeared after the first postoperative month. However, surgically induced astigmatism was significantly less in the 3.2 mm incision group than in the 5.5 incision group throughout the study. The Nd:YAG laser capsulotomy rate was higher in the silicone IOL group (23.5% at 3 years postoperatively) than in the PMMA IOL group (18.4%), but the difference was not statistically significant. Conclusion: Smaller incision cataract surgery led to earlier recovery of visual function in the short term and less induced astigmatism in the long term.

Postoperative membranous proliferation from the anterior capsulotomy margin onto the intraocular lens optic

Abstract We performed slitlamp microscopy and specular microscopy in 15 patients who had cataract surgery to determine the clinical course of postoperative membranous proliferation from the anterior capsulotomy margin onto the intraocular lens optic. Membranous proliferation observed in 11 of the 15 eyes eventually resolved in 10 eyes. We speculate that lens epithelial cells were the origin of the membrane.

Elschnig pearl formation along the posterior capsulotomy margin after neodymium: YAG capsulotomy

Purpose: To determine the incidence of Elschnig pearl formation along the capsulotomy margin (string of pearls) after neodymium:YAG (Nd:YAG) laser posterior capsulotomy and to elucidate its clinical features, predisposing factors, effect on visual function, and association with additional capsulotomy. Setting: Keio University Hospital, Tokyo, Japan. Methods: The records of 418 eyes that had had Nd:YAG posterior capsulotomy after cataract surgery were retrospectively reviewed. Of those, 315 were excluded for short follow‐up (fewer than 12 months) or insufficient clinical examination data. In the remaining 103 eyes, the incidence of string of pearls was calculated, and its clinical features, predisposing factors, effect on visual function, and correlation with additional capsulotomy were evaluated. Results: String of pearls was identified in 49 eyes (47.6%); 37 (75.5%) developed pearls within 1 year after Nd:YAG capsulotomy. The incidence was significantly higher in patients having intraocular lens implantation and continuous curvilinear capsulorhexis (CCC) than in those without (95.9 versus 61.1% and 97.9 versus 55.6%, respectively). No significant differences were found in patient age and sex, total Nd:YAG energy, and the presence of diabetes mellitus or high myopia. String of pearls caused visual disturbances in 17 eyes (34.7%). The rate of repeat capsulotomy was higher in patients with string of pearls than in those without (36.7 and 9.3%, respectively). Conclusions: String of pearls formation was a common and significant complication after Nd:YAG posterior capsulotomy. Intraocular lens implantation and CCC may promote its formation.

Clinical evaluation of a five-zone refractive multifocal intraocular lens

Purpose: To evaluate the clinical performance of a five‐zone refractive multifocal intraocular lens (AMO, model MPC‐25NB, Array®). Methods: We performed a retrospective clinical trial of 31 cataract patients (mean age 64.3 years). The parameters studied were intraoperative and postoperative complications, distance and near visual acuity, spectacle use, decreased number of corneal endothelial cells, contrast sensitivity, percentage of glare disability, near binocular vision, and depth of focus. Results: Intraoperatively, iris damage occurred in two eyes (4.2%), vitreous loss in one eye (2.1 %), and consecutive rupture of Zinn’s zonule and vitreous in one eye (2.1 %). Postoperatively, posterior capsule opacification was observed in two eyes (4.2%), temporary intraocular pressure increase in one eye (2.1 %), and cystoid macular edema in one eye (2.1%). Uncorrected distance visual acuity of 20/40 or better was achieved by 34 of 37 eyes (91.9%) with less than 1.5 diopters of preoperative keratometric astigmatism; best corrected distance acuity of 20/20 or better was achieved by 41 of 45 eyes (91.1 %). Near visual acuity with distance correction of 20/40 or better was achieved by 29 of 43 eyes (67.4%). These data were compared retrospectively with data from control patients who received monofocal lenses, and no significant differences in the decreased number of corneal endothelial cells were found. Mean contrast sensitivities were within normal range for all spatial frequencies. Percentage of glare disability and near binocular vision were within normal limits. Conclusions: Eyes implanted with the five‐zone refractive multifocal lens showed better near visual acuity than control eyes and compared favorably in other aspects of visual function, indicating that these lenses are effective and safe.

Lens epithelial cell proliferation onto the intraocular lens optic in vitro

Purpose: To determine how lens epithelial cells (LECs) proliferate onto an intraocular lens (IOL) after extracapsular cataract surgery. Setting: Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan. Methods: We cultured the capsular bags retaining LECs of eight human eye‐bank eyes and six rabbit eyes that had had extracapsular lens extraction with in‐the‐bag implantation of a poly(methyl methacrylate) (PMMA) IOL and a PMMA ring. Cell proliferation onto the IOL optic was monitored by a time‐lapse video system. Results: Cells proliferated onto the IOL optic via the anterior capsulotomy margin, the inner surface of the anterior capsule, and the posterior capsule. They formed cell sheets similar to the membranes observed in clinical cases. Conclusions: Since the cells proliferated from the anterior capsule as well as from the posterior capsule onto the IOL optic, the membranes observed clinically on the IOL optic may be LEC sheets.

Lens epithelial cell migration onto the posterior capsule in vitro

Purpose: To investigate lens epithelial cell (LEC) proliferation on the posterior capsule in an in vitro model. Setting: Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan. Methods: We cultured the cells remaining on the postoperative capsular bag and expanded the capsule with an open poly(methyl methacrylate) ring to simulate actual postoperative conditions. Using human and rabbit cadaver eyes, we monitored the migration and proliferation of LECs onto the postoperative capsular bag by time‐lapse videomicroscopy. Results: The remaining viable cells migrated onto the posterior capsule through the equator and directly from the anterior capsule. The cells typically proliferated in a monolayer because of contact inhibition of cell movement and division, but they proliferated in a multilayer at some regions where nonviable cells had accumulated and there were capsular folds. Conclusion: A means to block both routes of cell expansion must be developed to prevent LEC migration onto the posterior capsule.

Evaluation of a Zonal-progressive Multifocal Intraocular Lens

PURPOSEnTo determine the clinical usefulness of a five-zone refractive multifocal intraocular lens.nnnMETHODSnAfter more than 1 year of follow-up, we evaluated the visual function of 22 patients (36 eyes) who had received the MPC-25NB intraocular lens for distance and near visual acuity, kinetic visual acuity, and near contrast sensitivity, and for patient satisfaction.nnnRESULTSnOf 31 study eyes with less than 1.5 diopters of preoperative keratometric astigmatism, 28 (90.3%) achieved an uncorrected distance visual acuity of 20/40 or better; best-corrected distance visual acuity was 20/20 or better in 31 (86.1%) of 36 eyes. Near visual acuity with distance correction was 20/40 or better in 20 (60.6%) of 33 eyes. Kinetic visual acuity in these patients was comparable to that in patients with monofocal intraocular lenses. Distance visual acuity and near contrast sensitivity were below normal or within the low normal range. There was no significant difference in contrast visual acuity measured by variable contrast visual acuity charts between MPC-25NB and monofocal intraocular lens-implanted eyes (P > .05). Four (22.2%) of 18 patients did not require spectacles when the intraocular lens was implanted for emmetropia. Despite some complaints about near or night vision, all patients expressed satisfaction.nnnCONCLUSIONSnThe MPC-25NB lens provides a level of distance vision comparable to that of a monofocal intraocular lens and a useful level of near visual acuity without spectacles. However, we should carefully evaluate the indication for use of MPC-25NB in patients who require good near vision or night vision.