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Biomedical subjects

Shigeo Yaguchi

Publications and source records attributed to Shigeo Yaguchi.

13 recordsLinked to original sources
PubMed2007

Effect of ophthalmic solution components on acrylic intraocular lenses.

PURPOSE: To investigate the effect of ophthalmic solution components on the surface of acrylic intraocular lenses (IOLs). SETTING: Department of Opthalmology, Showa University School of Medicine. METHODS: Measurement of the contact angles of ophthalmic solutions on 3 acrylic IOLs was performed. The solutions were diclofenac sodium (Diclod), bromfenac sodium (Bronuck), betamethasone phosphate (Rinderon), dibekacin sulfate (Panimycin), polysorbate 80 (Tween 20), benzalkonium chloride, chlorobutanol, methylparahydroxybenzoate, and propylparahydroxybenzoate. The IOLs were incubated at 35 degrees C for 2 weeks in undiluted ophthalmic solutions and in 1:10 dilutions of ophthalmic solution components. The IOLs were sectioned and observed by scanning electron microscopy. RESULTS: The contact angle of Diclod and Bronuck solutions was the smallest. The contact angle of Rinderon and Panimycin was similar to that of distilled water. Scanning electron microscopy examination of IOLs incubated in ophthalmic solution components showed intralenticular changes. The IOLs immersed in ophthalmic solutions did not show any change, even after extended incubation. CONCLUSION: The chemical components of ophthalmic solutions, such as surfactants and solvents, permeate acrylic IOLs, suggesting the potential for long-term adverse effects of eyedrops in pseudophakic eyes.

Acrylic Resins↗
PubMed2006

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.

Adult↗
PubMed2005

[Automatic pulse system for conducting ultrasonic cataract operation].

PURPOSE: For use in phacoemulsification and aspiration (PEA) with a high frequency pulse sytem, we invented an Automated Pulse System(APS) in which the ultrasonic energy level and the percentage of ultrasonic pulses per second are regulated by a foot-pedal and suotion mechanism. METHOD: We compared the APS and the conventional continuous ultrasonic system experimentally by inserting a cataract model in an extracted aphakic pig eye. RESULT: Ultrasonic use time was not significantly different between the two methods. Gross ultrasonic energy and operation time were significantly decreased in the APS method (p < 0.05). CONCLUSION: Automatically, APS increases ultrasonic frequency and the percentage of ultrasonic pulses in nuclear emulsification. APS is an effective way to reduce the utilization of ultrasonic energy in the pulse mode without complicated foot-pedal control.

Animals↗
PubMed2004

Long-term follow-up of eye growth in pediatric patients after unilateral cataract surgery with intraocular lens implantation.

PURPOSE: To evaluate the refractive status, axial length, and refractive power of the cornea in pediatric patients after unilateral cataract surgery and intraocular lens implantation. METHODS: Refractive state, refractive power of cornea, and axial length were measured both in the operated and nonoperated eyes in 15 patients (age at surgery = 5 to 15 years; mean, 10.3) before and 4 to 15 years (mean, 9.7) after unilateral cataract surgery. RESULTS: After surgery, visual acuity was 20/40 or better in 79% of operated eyes. Myopic changes, representing the difference between postoperative refraction at last follow-up and postoperative refraction at 1 year after surgery, were noted in the operated eyes at the end of study (mean, -5.02 D), but there were no significant differences in axial length (Wilcoxon signed rank test P >.05) or refractive power of the cornea between operated and nonoperated eyes (paired Student t test P >.05). CONCLUSION: Myopic shift after cataract surgery with intraocular lens implantation may occur even in older children.

Adolescent↗
PubMed2004

Equilibrium water content and glistenings in acrylic intraocular lenses.

PURPOSE: To investigate the possible relationship between temperature and water absorption in acrylic intraocular lenses (IOLs). SETTING: Laboratory setting, Miyata Eye Clinic, Hiroshima, Japan. METHODS: The equilibrium water content (amount of water absorbed per weight of the resin x 100) in 2 hydrophobic acrylic IOLs (AcrySof MA60BM [Alcon] and Sensar AR40 [AMO]) was calculated at 30 degrees C, 40 degrees C, and 50 degrees C. The 2 IOLs were also subjected to 3 changes in temperature: from 37 degrees C to 35 degrees C, 39 degrees C to 35 degrees C, and 41 degrees C to 35 degrees C. They were incubated in physiological saline at the higher temperature for 2 hours and at the lower temperature for 30 days before being examined for glistening formation. RESULTS: The water content was higher in the AR40 IOL than in the MA60BM IOL at all temperatures. A temperature-dependent increase in water content was seen in both IOLs, greater in the MA60BM. With a temperature change from 37 degrees C to 35 degrees C, glistening formation was not observed in either IOL. With a temperature change from 39 degrees C to 35 degrees C, glistenings were observed in the MA60BM IOL, and with a temperature change from 41 degrees C to 35 degrees C, they were observed in both IOLs. CONCLUSION: The change in the equilibrium water content caused by temperature changes between 30 degrees C and 40 degrees C is an important factor in glistening formation, and thus an IOL featuring less temperature-dependent water absorption is less likely to form glistenings.

Absorption↗
PubMed2004

Clinical comparison of Healon5 and Healon in phacoemulsification and intraocular lens implantation; Randomized multicenter study.

PURPOSE: To compare the overall clinical performance during phacoemulsification and intraocular lens (IOL) implantation, the effect on intraocular pressure (IOP), and the effect on corneal endothelium of Healon5 (sodium hyaluronate 2.3%) and Healon (sodium hyaluronate 1.0%) ophthalmic viscosurgical devices (OVDs). SETTING: Multicenter study. METHODS: In this randomized prospective clinical study, the performance of Healon5 (viscoadaptive; dispersive and cohesive) and Healon (cohesive) during cataract surgery was evaluated in 157 patients, 79 with Healon5 and 78 with Healon. Surgeons evaluated the following on a 5-point scale: retention during phacoemulsification (primary endpoint), ease of injection, anterior chamber maintenance during continuous curvilinear capsulorhexis (CCC), facilitation of IOL implantation, and ease of removal from the eye. Masked examiners other than the surgeon performed the following measurements: IOP preoperatively and 5 and 24 hours, 7 days, and 3 months postoperatively; corneal thickness before and 24 hours, 7 days, and 3 months postoperatively; and corneal endothelial cell count preoperatively and 3 months postoperatively. RESULTS: Intraocular retention during phacoemulsification was assessed as good or very good in 77% in the Healon5 group and 8% in the Healon group; the difference was statistically significant (P<.0001, Wilcoxon rank sum test). The Healon5 group had significantly better scores for anterior chamber maintenance during CCC (P<.0001) and facilitation of IOL implantation (P =.032), and the Healon group had significantly better scores for ease of injection (P<.0001) and ease of removal (P<.0001). There were no statistically significant between-group differences in IOP, corneal endothelial cell count, or corneal thickness. CONCLUSIONS: Surgeons rated Healon5 better than Healon in retention during phacoemulsification, anterior chamber maintenance during CCC, and facilitation of IOL implantation. They assessed Healon as easier to inject and remove. There was no difference in safety-related parameters between the 2 OVDs. These findings indicate that Healon5 is effective in cataract surgery.

Aged↗
PubMed2004

[Comparison of surface light scattering of acrylic intraocular lenses made by lathe-cutting and cast-molding methods--long-term observation and experimental study].

PURPOSE: To compare the long-term clinical and experimental results of soft acrylic intraocular lenses(IOLs) manufactured by the lathe-cut(LC) method and by the cast-molding(CM) method. METHODS: This was a retrospective study of 20 patients(22 eyes) who were examined in a 5- and 7-year follow-up study. Sixteen eyes were implanted with polyacrylic IOLs manufactured by the LC method and 6 eyes were implanted with polyacrylic IOLs manufactured by the CM method. Postoperative measurements included best corrected visual acuity, contrast sensitivity, biomicroscopic examination, and Scheimpflug slit-lamp images to evaluate surface light scattering. Scanning electron microscopy and three-dimensional surface analysis were conducted. RESULTS: At 7 years, the mean visual acuity was 1.08 +/- 0.24 (mean +/- standard deviation) in the LC group and 1.22 +/- 0.27 in the CM group. Surface light-seatter was 12.0 +/- 4.0 computer compatible tapes(CCT) in the LC group and 37.4 +/- 5.4 CCT in the CM group. Mean surface roughness was 0.70 +/- 0.07 nm in the LC group and 6.16 +/- 0.97 nm in the CM group. CONCLUSION: Acrylic IOLs manufactured by the LC method are more stable in long-termuse.

Acrylic Resins↗
PubMed2003

Surface scattering in implanted hydrophobic intraocular lenses.

PURPOSE: To describe surface scattering, a new phenomenon in polyacrylic intraocular lenses (IOLs), and discuss the possible cause of this finding. SETTING: Showa University, Fujigaoka Hospital, Yokohama, Kanagawa, Japan. METHODS: This observational case series involved 40 patients who received the AcrySof(R) IOL (Alcon Laboratories, Inc.) as part of a clinical trial in 1991. Four patients (5 eyes) were evaluated. Thirty-three patients had the same surgery in 1999, and the findings in these patients were compared with those in the earlier patients. Lens surface scattering was evaluated by area densitometry using Scheimpflug photography. No statistical analysis was done because of the small sample size. RESULTS: The 5 IOLs implanted in 1991 showed various degrees of surface scattering. The degree of scattering was greater than that in the 1999 group. There was no degradation in visual performance and no manifestation of intraocular inflammation or other adverse effect from the IOLs in either group. Attempts to remove foreign material on the IOL using the neodymium:YAG (Nd:YAG) laser were unsuccessful. CONCLUSIONS: The surface scattering did not appear to be due to deposition of foreign material on the IOL surface. Densitometry and the results of Nd:YAG laser treatment suggest that the changes occurred in the near-surface layer. Phase separation of water near the IOL surface in the inherently hydrophobic material may explain the phenomenon. Newer AcrySof IOLs appear to have less surface scattering.

Acrylates↗
PubMed2002

[Light scattering observed on the surface of acrylic intraocular lenses ten years after implantation].

PURPOSE: To report the long-term status of acrylic intra-ocular lenses. CASES: We describe two cases of increased light scattering on the surface of acrylic intraocular lenses ten years after implantation. The scattering was non-symptomatic and visual acuity was normal. Biomicroscopy and a Scheimpflug photography system showed that the scattering apparently derived from the anterior surface of the lens, but no deposit or membranous structure was observed on the lens surface. CONCLUSION: Surface scattering from acrylic intra-ocular lenses is a new finding in long-term observations. A possible etiology may be structural changes of the internal polymer.

Acrylic Resins↗
PubMed2002

[Experimental study of glistening in silicone intraocular lenses].

PURPOSE: To assess the whether glistening(GP) occurs on silicon lenses. METHODS: ALLERGAN, SI-40NB and CANON STAAR, AQ110NV lenses(Alcon MA60BM control). The lenses were immersed in 50 degrees C physiological saline solution for 2 hours, and then immersed in 35 degrees C physiological saline solution. Changes in the lens were observed regularly with a slit lamp microscope until the 90th day. RESULTS: Numerous microvacuoles of 10 microns diameter occurred in the MA60BM and of several microns in the SI40NB. Some clouding was seen in the AQ110 NV. CONCLUSION: The presence of numerous microvacuoles in the SI40NB means there may be GP. The light clouding in the AQ110NV that was resolved with drying is thought to be due to particles in the material which cause discoloration.

Biocompatible Materials↗
PubMedDate not supplied

Three-year prospective randomized study of incidence of posterior capsule opacification in eyes treated with topical diclofenac and betamethasone.

PURPOSE: To investigate the incidence of posterior capsule opacification (PCO) in eyes treated with diclofenac sodium (DFNa) and betamethasone phosphate (BMS) ophthalmic solutions. METHODS: A total of 200 eyes with silicone intraocular lens implantation were treated with topical agents for 3 months postoperatively. Twenty-six cases of the DFNa group and 34 of the BMS group met the criteria, and the severity of PCO was evaluated after 3 years. RESULTS: The results of axial densitometry by Scheimpflug photography were 27.8 computer-compatible tapes (CCT) in the DFNa-treated group and 32.6 CCT in the BMS-treated group (p = 0.1539). Posterior capsulotomy was performed in 11.5% of the DFNa group and 17.6% of the BMS group (p = 0.8375). The photographic grading of PCO showed no difference. CONCLUSION: The incidence of PCO in eyes treated with DFNa appears to be equal to that after BMS treatment.

Aged↗
PubMedDate not supplied

Lens epithelial cell migration between posterior capsule and intraocular lens with variously finished posterior optic edge and two haptic angulations.

PURPOSE: To compare lens epithelial cell migration between intraocular lens (IOL) optics and the posterior capsule of IOLs with various edges and haptic angulations. METHODS: Experimental acrylic IOLs with 3 types of finishing (none, polishing, tumbling and polishing) and 2 types of haptic angulation (10 and 15 degrees ) as well as 3 (AcrySof MA30BA, Sensar AR40, CeeOn 911) clinically implanted IOLs were inserted in rabbit eyes. Scanning electron-microscopic examination of IOLs was carried out before surgery and histological examination of lens capsules 3 weeks after surgery. The grading of lens epithelial cell migration under the IOL was made by scoring. RESULTS: Scanning electron-microscopic examination showed that the optic edge sharpness decreased according to the finishing in experimental IOLs. The AcrySof and CeeOn lenses had sharp edges and the Sensar had a rounded edge. The migration score was highest in the IOL with a rounded edge whereas it was lowest in IOLs with a sharp edge and large haptic angulation. There was no significant difference between the scores of clinically implanted IOLs. CONCLUSION: Sharpness of the optic edge may be a critical factor for the prevention of posterior capsule opacification and more important than haptic angulation in acrylic IOLs.

Acrylic Resins↗