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At least 793 records · Page 44Linked to original sources
PubMed2001

Dense opacification of the optical component of a hydrophilic acrylic intraocular lens: a clinicopathological analysis of 9 explanted lenses.

PURPOSE: To report clinical, pathological, histochemical, ultrastructural, and spectrographic analyses of explanted hydrophilic acrylic intraocular lenses (IOLs) obtained from patients who had visual disturbances caused by postoperative opacification of the lens optic. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA, and Ege University, Alsancak Izmir, Turkey. METHODS: Nine hydrophilic IOLs (SC60B-OUV, MDR Inc.) were explanted from 9 patients with decreased visual acuity. Most patients became symptomatic approximately 24 months after uneventful phacoemulsification and IOL implantation. Opacification was noted and appeared clinically to be associated with a fine granularity within the substance of the IOL optic. The IOLs were forwarded to the center and examined by gross and light microscopy. Full-thickness cut sections of the optics were stained with 1% alizarin red and the von Kossa method (special stains for calcium). Some were submitted for scanning electron microscopy and energy dispersive x-ray spectroscopy. RESULTS: Microscopic analyses revealed multiple fine, granular deposits of variable sizes within the lens optics, usually distributed in a line parallel to the anterior and posterior curvatures of the optic, with a clear zone just beneath the optic surface. The deposits stained positive with alizarin red and the von Kossa method. Energy dispersive x-ray spectroscopy of the internal substance of sectioned IOLs demonstrated the presence of calcium within the deposits. CONCLUSION: This is the first clinicopathological report of optic opacification occurring with this hydrophilic acrylic IOL model. Studies of similar cases with this lens should be done to determine the incidence and possible mechanisms of the phenomenon.

Acrylic Resins↗
PubMed2002

Spontaneous disinsertion of a haptic from a 3-piece acrylic foldable intraocular lens after surgery.

A 49-year-old man with cataracts had uneventful phacoemulsification, continuous curvilinear capsulorhexis, and implantation of an MA30BA acrylic foldable intraocular lens (IOL) in the bag. One week later, 1 haptic spontaneously dropped off and the optic dislocated into the anterior chamber. The IOL was surgically removed and replaced with a new acrylic foldable IOL. Examination of the explanted IOL revealed that the loop hole was not created in the middle of the side face, leading to in vivo detachment of the haptic postoperatively.

Acrylic Resins↗
PubMed2002

In vitro comparison of glistening formation among hydrophobic acrylic intraocular lenses(1).

PURPOSE: To compare glistening formation induced by temperature stressing in vitro among hydrophobic acrylic intraocular lenses (IOLs) available in the United States. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Wagon Wheel (WW) packaged 1-piece AcrySof IOLs (Alcon), WW-packaged 3-piece AcrySof IOLs, and Sensar IOLs (Allergan Medical Optics) were analyzed in vitro for 5 consecutive days. Ten IOLs of each type were inserted into viewing chambers filled with balanced salt solution, maintained at 37 degrees C, and evaluated every 24 hours at 37 degrees C and then, after a 2-hour cooling, at room temperature. The IOLs were examined by slitlamp to quantify glistenings and by digital photography to determine glistening size. RESULTS: The glistening quantity was minimal and did not differ among IOL types at 37 degrees C. The glistenings were smallest in the 1-piece AcrySof IOLs (P <.001): 6.3 microm versus 11.5 microm in the Sensar and 13.4 microm in the 3-piece AcrySof. Upon cooling, the glistening quantity increased dramatically in the 1-piece AcrySof IOLs (P <.008) and was the highest among the IOL types at room temperature (P <.001). The mean glistening size was 7.7 microm. The 3-piece AcrySof IOLs showed a significant decrease in slitlamp-countable glistenings but acquired a dense haze seen as minute glistenings (4.0 microm) at x80 magnification. The glistening quantity in the Sensar IOLs was fairly stable upon cooling; a statistical increase was seen on the last day (P =.007). Cooling nearly doubled the size of the Sensar glistenings, which were the largest at room temperature, 21.7 microm (P <.001). CONCLUSIONS: Glistening quantity varied among hydrophobic acrylic IOLs and was temperature dependent. Sensar IOLs were more stable than the 2 other IOL types. The glistening phenomenon must be studied further to eliminate the problem.

Acrylic Resins↗
PubMed2003

Unfolder lens injection system with acrylic intraocular lenses: retrospective study.

PURPOSE: To examine the efficacy of using the Unfolder Sapphire series system (Allergan) for implanting acrylic intraocular lenses (IOLs) with a 6.0 mm optic (Sensar AR40, Allergan). SETTING: Ambulatory day-surgery center. METHODS: Phacoemulsification was performed using topical anesthesia. The Unfolder injection system was used to insert a Sensar AR40 acrylic IOL. Data on complications and the success of implantation were collected retrospectively. RESULTS: Two hundred two consecutive patients having implantation of the Sensar IOL with the Unfolder system were examined. Three problems related to the Unfolder injector were identified. Another patient required an anterior vitrectomy, sulcus IOL implantation with the Unfolder, and optic capture; the complication was not related to the Unfolder system. Sulcus implantation was relatively easy with the Unfolder. CONCLUSION: Implantation of the Sensar AR40 IOL with the Unfolder system was easy to perform, and no serious complications occurred.

Acrylic Resins↗
PubMed2003

Postoperative change in effective lens position of a 3-piece acrylic intraocular lens.

PURPOSE: To study the change in postoperative position of an angulated, 3-piece, foldable acrylic intraocular lenses (IOLs) and evaluate the effect of a sharp posterior optic edge compared with that of a round optic edge on the change in postoperative anterior chamber depth (ACD). SETTING: Department of Ophthalmology, University of Vienna, Vienna, Austria. METHODS: This randomized intraindividual-comparison study comprised 104 eyes of 52 patients with age-related cataract. Patient received a sharp-edged Sensar OptiEdge AR40e IOL (Allergan Surgical) in 1 eye and a round-edged Sensar AR40 IOL in the other eye. Postoperative follow-up included ACD measurement by partial coherence interferometry and evaluation of the capsulorhexis area by standardized retroillumination photography at 1 day, 1 week, and 1 and 6 months. RESULTS: A decrease in ACD during the first postoperative week was followed by a small increase in ACD during the first 6 months. There was no significant difference between the sharp-edged group and the round-edged group. CONCLUSIONS: The angulated 3-piece acrylic IOLs showed significant forward movement over the first postoperative 6 months. Although the change in refraction was small, there was variability among patients. The sharp posterior optic edge design did not affect the IOL's movement in the capsular bag.

Acrylic Resins↗
PubMed2004

Late postoperative opacification of MemoryLens hydrophilic acrylic intraocular lenses: case series and review.

PURPOSE: To report clinical and spectrographic analyses of 2 explanted hydrophilic acrylic intraocular lenses (IOLs). SETTING: John A. Moran Eye Center, Salt Lake City, Utah, USA, and Johannes Gutenberg-University, Department of Ophthalmology, Mainz, Germany. METHODS: We report 6 cases of opacification of MemoryLens IOLs (Ciba Vision) that occurred approximately 2 years after implantation. The anterior and posterior surfaces of the IOLs had a white, frosted appearance, and the IOLs' interior looked brown, similar to the appearance of a brunescent cataract. Two of the IOLs were explanted because of a significant decrease in visual acuity. The IOLs were sent for further clinicopathologic analysis including scanning electron microscopy and energy dispersive x-ray spectroscopy (EDX). RESULTS: Microscopic analysis revealed multiple, fine, granular deposits of various sizes on the surface of the lens optics. The EDX analysis showed the presence of calcium within the deposits. CONCLUSIONS: Our cases show that hydrophilic acrylic IOLs can opacify even years after implantation. Analysis of the explanted IOLs revealed calcification.

Acrylic Resins↗
PubMed2004

Analysis of cytoskeletal proteins in posterior capsule opacification after implantation of acrylic and hydrogel intraocular lenses.

PURPOSE: To analyze selected lens cytoskeletal proteins in posterior capsule opacification (PCO) 2 weeks after intraocular lens (IOL) implantation in rabbits. SETTING: Department of Ophthalmology, Dokkyo University School of Medicine, Tochigi, Japan. METHOD: Eight 10-week-old albino rabbits were prepared and anesthetized for phacoemulsification and aspiration of the crystalline lens and implantation of an acrylic or a hydrogel IOL. Two weeks postoperatively, the rabbits were killed and the IOLs removed for immunohistochemistry. Deparaffinized tissue sections were processed with antibodies against alpha-smooth muscle actin (alpha-SMA) and beta-crystallin to observe the types of PCO with the 2 IOL types. The proteins in the PCO tissue and the normal lens were homogenized, centrifuged, and analyzed using SDS-polyacrylamide gel electrophoresis (SDS-PAGE) densitometric analysis and Western immunoblotting for actin and vimentin. RESULTS: Immunohistochemistry demonstrated a fibroblastic cell type expressing alpha-SMA and partial regeneration of epithelial cells, resulting in a lenticular structure that stained irregularly for beta-crystallin. The immunoreactivity of fibroblast-like cells to beta-crystallin appeared weaker than that of the regenerated lenticular structure. SDS-PAGE showed variability in the content of cytoskeletal proteins in the insoluble fractions of the PCO. Degradation of the cytoskeletal components was greater with the acrylic IOL than with the hydrogel IOL. CONCLUSION: Cytoskeletal proteins expressed during the formation of PCO and IOL implantation may have potential as therapeutic target proteins to improve the biocompatibility of IOLs.

Acrylic Resins↗
PubMed1996

Evaluation of the first 50 ACR360 acrylic intraocular lens implantations.

PURPOSE: To evaluate the clinical results of implantation of the ACR360 soft acrylic intraocular lens (IOL). SETTING: Civico Hospital, Lugano, Switzerland. METHODS: This prospective, medium-term study comprised the first 50 consecutive patients who had small incision scleral tunnel phacoemulsification and implantation of an ACR360 acrylic IOL (loptex/Allergan). Intraoperative and postoperative complications, best corrected visual acuity (BCVA), intraocular pressure (IOP), preoperative and postoperative astigmatism, and IOL centration were recorded. Mean follow-up was 12 months +/- 3 (SD). RESULTS: One day postoperatively, 94% of best cases (n = 46) achieved a BCVA of 20/40 or better and 54%, 20/25 or better. At 2 weeks, 98% had 20/40 or better and 78%, 20/25 or better. After 6 months, all patients achieved a BCVA of 20/40 or better and 83%, 20/25 or better. No statistically significant changes in keratometric astigmatism or IOP occurred. CONCLUSIONS: The ACR360 IOL gave clinical results comparable to those of other foldable lenses; however, it can also be implanted in cases of intraoperative capsular complications and in eyes with intravitreal silicone oil. Development of an injecting system for implantation and substituting the polypropylene loops with poly(methyl methacrylate) haptics could improve lens quality.

Acrylates↗
PubMedDate not supplied

Optimal folding axis for acrylic intraocular lenses.

Acrylic intraocular lenses (IOLs) are easier to insert than foldable lenses of other materials. In addition to material properties, the structure of acrylic lenses allows an optimal folding angle along the 10 to 4 o'clock axis. Folding the IOL along this axis simplifies the manipulation of the leading haptic during insertion and places the trailing haptic within the capsular bag before the folded optic is released.

Acrylates↗
PubMed2000

Interpseudophakos intraocular lens surface opacification as a late complication of piggyback acrylic posterior chamber lens implantation.

We present a case involving opacification of the apposing surfaces of 2 acrylic intraocular lenses (IOLs) that had been implanted in a piggyback fashion 16 months previously. Clinical observations derived from our experience with piggyback acrylic lens implantation are presented, along with a discussion of late complications of piggyback IOL implantation and recommendations.

Acrylic Resins↗
PubMed1999

Treatment and posttreatment effects of acrylic splint Herbst appliance therapy.

This study evaluated the skeletal and dentoalveolar changes induced by acrylic splint Herbst therapy of Class II malocclusion. The treated group comprised 55 subjects with Class II malocclusion treated with the acrylic splint Herbst appliance followed by comprehensive edgewise therapy. The mean age at Time 1 (immediately before treatment) was 12 years and 10 months +/- 1 year and 2 months. The mean age at Time 2 (immediately after debonding of the Herbst appliance) and Time 3 (posttreatment) was 13 years and 10 months +/- 1 year and 2 months and 15 years and 2 months +/- 1 year and 4 months, respectively. The two control groups were one group of 30 subjects with untreated Class II malocclusion and another group of 33 subjects with Class I occlusion. The three groups were homogeneous as to the stage of maturation of cervical vertebrae at all observation times. A modification of Pancherz's cephalometric analysis was applied to the lateral cephalograms of the three groups at Time 1, Time 2, and Time 3. Linear and angular measurements for mandibular dimensions, cranial base angulation, and vertical relationships were added to the original analysis. Differences for all the variables from Time 1 to Time 2 (active treatment effects), from Time 2 to Time 3 (posttreatment effects), and from Time 1 to Time 3 (overall treatment effects) were calculated for the treated group and contrasted to corresponding differences of both untreated groups by means of ANOVA (P <.05). The study showed that two thirds of the achieved occlusal correction was due to skeletal effects and only one third to dentoalveolar adaptations. Both skeletal and dentoalveolar effects were due mainly to changes in mandibular structures. A significant amount of relapse in molar relationship occurred during the posttreatment period, and this change could be ascribed to the mesial movement of the upper molars.

Acrylic Resins↗
PubMed2002

Thiolated polymers: self-crosslinking properties of thiolated 450 kDa poly(acrylic acid) and their influence on mucoadhesion.

This study examined the rheological and mucoadhesive properties of a self-crosslinking anionic thiolated polymer in vitro. Mediated by a carbodiimide, L-cysteine was covalently bound to poly(acrylic acid) of 450 kDa molecular mass. The resulting thiolated polymers (conjugates I and II) contained 90.5+/-15.8 and 511.6+/-52 micromol thiol groups per gram polymer, respectively (mean+/-S.D., n=3). The amount of covalently attached cysteine was therefore dependent on the concentration of carbodiimide used for the coupling reaction. Both conjugates (3%, m/v) were capable of forming inter- and/or intramolecular disulfide bonds in 100 mM phosphate buffer pH 6.8. Consequently, the apparent viscosity of conjugates I and II increased 12- and 10-fold, respectively, within 24 h of incubation at 37 degrees C. Further, rheological synergy was observed by mixing equal volumes of polymer (unmodified as well as modified) with a mucin solution. A six-fold increase in viscosity immediately after mixing could be observed for the conjugate II/mucin mixture. This clearly indicates the high interaction potential of self-crosslinking thiomers with the mucus gel layer. Mucoadhesion studies confirmed the rheological results. Tablets based on conjugate II remained attached on freshly excised porcine mucosa for about 25 times longer than the corresponding controls, which is the longest time of mucoadhesion ever found among anionic thiomers. Due to the results of the present study, self-crosslinking thiolated poly(acrylates) of 450 kDa represent very promising excipients for the development of various mucoadhesive drug delivery systems.

Acrylic Resins↗
PubMed1999

Tackiness of acrylic and cellulosic polymer films used in the coating of solid dosage forms.

The objective was to determine the tackiness of acrylic and cellulosic polymer films in order to make predictions on the tackiness (agglomeration) of coated dosage forms during coating and curing. Force-displacement curves of the detachment process of two polymeric films were used as a measure of tackiness. Various polymers (cellulosic (Aquacoat and acrylics (Eudragit RS 30D, L 30D, NE 30D)), plasticizers (triacetin, triethyl citrate, tributyl citrate, acetyltributyl citrate) and anti-tacking agents (talc and glyceryl monostearate) were investigated. The order of tackiness for films prepared from the different aqueous polymer dispersions was in order of Eudragit NE 30D > RS 30D > RL 30D > Aquacoat. The tackiness increased with increasing plasticizer concentration due to the softening of the polymer. A correlation between the minimum film formation temperature and the tackiness was observed, however, no correlation between the tackiness and the lipophilicity of the plasticizer was seen. Talc and glyceryl monostearate (GMS) reduced the tackiness of the films significantly, with GMS being effective at much lower concentrations. Curing of Eudragit RS 30D-coated theophylline beads at temperatures higher than 40 degrees C in an irreversible agglomeration of the beads and damage of the coating upon separation of the beads. This resulted in a faster release than with uncured beads. Blending the beads with talc just prior to the curing step eliminated the agglomeration and therefore film damage, even at a curing temperature of 60 degrees C.

Acrylates↗
PubMedDate not supplied

Mucin/poly(acrylic acid) interactions: a spectroscopic investigation of mucoadhesion.

Studies using infrared, (1)H and (13)C nuclear magnetic resonance, and X-ray photoelectron spectroscopies and differential scanning calorimetry support the hypothesis that hydrogen bonds, formed between the carboxylic acid functionality of the mucoadhesive material poly(acrylic acid) and the glycoprotein component of mucus, play a significant role in the process of mucoadhesion. There are fewer H-bonded interactions between the components than within the bulk of the pure mucoadhesive agent. The pH of the medium influences the structures of both the poly(acrylic acid) and the mucus, which, in turn, determine the nature and the extent of mucoadhesive interactions.

Acrylic Resins↗
PubMedDate not supplied

Metalloinitiation routes to biocompatible poly(lactic acid) and poly(acrylic acid) stars with luminescent ruthenium tris(bipyridine) cores.

Poly(lactic acid) (PLA) and poly(acrylic acid) (PAA) biomaterials with luminescent ruthenium tris(bipyridine) centers couple drug delivery and imaging functions. Hydrophobic [Ru(bpyPLA2)3](PF6)2 (1) was generated from [Ru[bpy(CH2OH)2]3](PF6)2 in bulk monomer using 4-(dimethylamino)pyridine as the catalyst. The bromoesters, [Ru[bpy(CH2OR)2]3](PF6)2, [Ru[bpy(C13H27)2][bpy(CH2OR]2](PF6)2 (4), and [Ru[bpy(PLAOR)2]3]2+ (9) (R=COCBr(CH3)2), served as initiators for tert-butyl acrylate (tBA) polymerization. Conversion of PtBA to PAA via hydrolysis affords water soluble materials, [Ru(bpyPAA2)3]2+ (7) and [Ru[bpy(C13H27)2](bpyPAA2)2]2+ (8) and the amphiphilic star polymer [Ru[bpy(PLA-PAA)2]3)](PF6)2 (11), which is soluble in a H2O/CH3CN (1:1) mixture. Luminescence excitation and emission spectra of the Ru polymers were in agreement with the parent [Ru(bpy)3]2+ chromophore (lambdaex=468, lambdaem=621 nm). Lifetimes of tau approximately 700 ns in both air and nitrogen atmospheres are typical for most materials; however, the amphiphilic star block copolymer 11 is quenched by oxygen to some degree. Thermal analysis shows the expected glass transitions for the polymeric ruthenium complex materials.

Acrylic Resins↗
PubMed2006

Design of mucoadhesive polymeric films based on blends of poly(acrylic acid) and (hydroxypropyl)cellulose.

Mixing of aqueous solutions of poly(acrylic acid) and (hydroxypropyl)cellulose results in formation of hydrogen-bonded interpolymer complexes, which precipitate and do not allow preparation of homogeneous polymeric films by casting. In the present work the effect of pH on the complexation between poly(acrylic acid) and (hydroxypropyl)cellulose in solutions and miscibility of these polymers in solid state has been studied. The pH-induced complexation-miscibility-immiscibility transitions in the polymer mixtures have been observed. The optimal conditions for preparation of homogeneous polymeric films based on blends of these polymers have been found, and the possibility of radiation cross-linking of these materials has been demonstrated. Although the gamma-radiation treatment of solid polymeric blends was found to be inefficient, successful cross-linking was achieved by addition of N,N'-methylenebis(acrylamide). The mucoadhesive potential of both soluble and cross-linked films toward porcine buccal mucosa is evaluated. Soluble films adhered to mucosal tissues undergo dissolution within 30-110 min depending on the polymer ratio in the blend. Cross-linked films are retained on the mucosal surface for 10-40 min and then detach.

Acrylic Resins↗
PubMed1990

Cluster analysis of acrylates to guide sampling for toxicity testing.

A set of 143 acrylates drawn from the TSCA inventory have been investigated for structurally defined clusters of compounds to simplify sampling for future toxicity screening. Each acrylate was represented by eight descriptors calculated from the molecular structure. Several standard clustering methods have been used to find five natural clusters of compounds. These five clusters are largely populated by compounds with similar chemical attributes with separate clusters formed for compounds with high absolute partial atomic charges, hydrophobic compounds, small compounds, halogenated compounds, and large or oligomeric compounds.

Acrylates↗