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Biomedical subjects

L Werner

Publications and source records attributed to L Werner.

At least 55 records · Page 3Linked to original sources
PubMed2000

Dye-enhanced cataract surgery. Part 1: anterior capsule staining for capsulorhexis in advanced/white cataract.

PURPOSE: To evaluate anterior capsule staining using 3 dyes to perform continuous curvilinear capsulorhexis (CCC) in postmortem human eyes with advanced/white cataract. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: In experimental closed-system surgery, CCC was performed in 12 postmortem human eyes with cataract after the anterior capsule was stained with 3 capsule dyes (fluorescein sodium 2%, indocyanine green [ICG] 0.5%, and trypan blue 0.1%). Two commonly used techniques for capsule staining were also compared: staining within an air bubble and intracameral subcapsular injection of dye. RESULTS: In all globes, CCC was uneventful using the 3 dyes and with both techniques. With the intracameral subcapsular injection, the dye remained trapped in the subcapsular space in contact with the posterior surface of the anterior capsule, allowing enough time to perform any maneuver. The staining provided by ICG, at the concentration used, was slightly superior to that of the other dyes. Leakage of fluorescein sodium into the vitreous cavity was seen using the Miyake-Apple posterior video/photographic technique. CONCLUSION: Intracameral subcapsular injection of ICG allowed the easiest recognition of the capsular flap by staining the posterior surface of the anterior capsule and without leaking into the vitreous cavity.

Cadaver↗
PubMed2000

Dye-enhanced cataract surgery. Part 3: posterior capsule staining to learn posterior continuous curvilinear capsulorhexis.

PURPOSE: To evaluate the use of 2 dyes for staining the posterior capsule to enhance visualization during posterior continuous curvilinear capsulorhexis (PCCC). SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Indocyanine green 0.5% (ICG) and trypan blue 0.1% were used to stain the posterior capsule for performing PCCC in 8 human eyes obtained postmortem. The eyes were prepared according to the posterior video technique of Miyake-Apple. After CCC and hydrodissection/delineation were performed, the nucleus was carefully delivered by hydroexpression. Cortical cleanup was completed by irrigation/aspiration. The posterior capsule was stained by instilling 1 microdrop of ICG (4 eyes) or trypan blue (4 eyes) in the capsular bag. A PCCC was then performed by 2 independent surgeons (4 eyes/surgeon) not familiar with this technique. Each surgeon also performed PCCC in 2 eyes without the use of dye. RESULTS: Both dyes facilitated the performance of PCCC after staining the otherwise transparent posterior capsule. It was easier to differentiate the stained posterior capsule flap from the underlying transparent anterior hyaloid phase of the vitreous. In addition, optic capture of an intraocular lens, with or without anterior vitrectomy, was easily accomplished because of the enhanced visualization by posterior capsule staining. CONCLUSIONS: Posterior capsule staining can be successfully used to learn and perform the PCCC procedure, combined with optic capture, anterior vitrectomy, or both.

Cadaver↗
PubMed2000

Dye-enhanced cataract surgery. Part 2: learning critical steps of phacoemulsification.

PURPOSE: To use capsule dyes to enhance visualization to learn and perform various critical steps of the phacoemulsification procedure in a laboratory setting using postmortem human eyes. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Indocyanine green 0.5% (ICG) and trypan blue 0.1% were used to enhance visualization for performing critical steps of phacoemulsification in 8 human eyes obtained postmortem. All eyes were prepared according to the Miyake-Apple posterior video technique. After a continuous curvilinear capsulorhexis (CCC) was made, the dyes were used to enhance visualization for hydrodissection, hydrodelineation, and various maneuvers for nuclear emulsification and cortical cleanup. In 8 eyes, all the aforementioned steps were performed without using dye (control group). RESULTS: Both dyes helped enhance visualization during the critical steps of phacoemulsification. The use of a dye solution instead of balanced salt solution (BSS) for hydrodissection/delineation helped localize the complete plane of cleavage between the capsule and cortex and the nucleus-epinucleus complex. During various nuclear sculpting maneuvers, the use of dye helped visualization of the position of the phaco tip and its relation to the posterior capsule. It also helped localize remaining cortical fibers, facilitating complete cleaning of the capsular bag. CONCLUSIONS: Dye-enhanced cataract surgery was useful in learning various critical steps of phacoemulsification in a wet laboratory setting.

Cadaver↗
PubMed2000

Opacification of piggyback IOLs associated with an amorphous material attached to interlenticular surfaces.

PURPOSE: To report the pathological and ultrastructural features and interval surgical management of an atypical case of opacification between piggyback intraocular lenses (IOLs). SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, and Nature Coast EyeCare Institute and Surgery Center, Perry, Florida, USA. METHODS: Opacification between 2 acrylic piggyback lenses was observed 16 months after implantation, with decreased best corrected visual acuity and a hyperopic shift. Elschnig pearls were observed in the peripheral interface between the lenses, and the central interface was occupied by an amorphous material. The pearls were surgically aspirated, but attempts to remove the central material were unsuccessful. The lenses were explanted and sent to the laboratory. Staining with hematoxylin and eosin (H&E), examination under a light microscope, and scanning electron microscopic analysis were performed. RESULTS: The surfaces of the anterior IOL were relatively clear. The amorphous material, mostly attached to the center of the anterior surface of the posterior IOL, was homogeneously stained with H&E. No cell nucleus was observed in this region. Scanning electron microscopy showed that the IOL edge presented a smooth, regular surface relatively free of deposits. The most central region was covered by an irregular layer of an amorphous compact material with some cracks, fissures, or both on its surface. CONCLUSIONS: Although the exact composition of the material between the lenses could not be established, hypotheses were advanced to understand the pathological mechanism associated with this condition. This case is different from those in previous reports of opacification composed of cortex and cells between piggyback IOLs.

Acrylates↗
PubMed2000

Adhesion of fibronectin, vitronectin, laminin, and collagen type IV to intraocular lens materials in pseudophakic human autopsy eyes. Part 2: explanted intraocular lenses.

PURPOSE: To evaluate fibronectin, vitronectin, laminin, and collagen type IV adhesion to poly(methyl methacrylate) (PMMA), silicone, hydrophobic soft acrylate, and hydrogel intraocular lenses (IOLs) in human pseudophakic autopsy eyes. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Thirty-two autopsy eyes containing PMMA, silicone, soft acrylate, or hydrogel IOLs were assessed. The IOLs were explanted from the capsular bag, and both sides of the IOLs were immunohistochemically stained for fibronectin, vitronectin, laminin, or collagen type IV. The number of cells on the IOL surfaces was counted. The capsular bag from 1 eye containing a soft acrylate IOL was examined for fibronectin and vitronectin. RESULTS: Hydrophobic soft acrylate IOLs had significantly more fibronectin adhering to their surfaces than PMMA (P <.01) or silicone (P <.01) IOLs, as well as more vitronectin. Silicone IOLs had more collagen type IV adhesion than the other IOLs (P <.05-.06). Collective protein adhesion differed significantly between soft acrylate IOLs and PMMA and silicone IOLs, but not between PMMA and silicone IOLs. CONCLUSIONS: The greater amount of protein on the hydrophobic soft acrylate (AcrySof(R)) IOLs seems to support an adhesive mechanism for their attachment to the capsular bag. Fibronectin and vitronectin have functional domains to bind them to lens epithelial cells and the collagenous capsule. This kind of attachment could be a true bioactive bond and may be 1 reason the PCO and neodymium:YAG capsulotomy rates are lower in eyes with a soft acrylate IOL.

Acrylic Resins↗
PubMed2000

Adhesion of fibronectin, vitronectin, laminin, and collagen type IV to intraocular lens materials in pseudophakic human autopsy eyes. Part 1: histological sections.

PURPOSE: To evaluate fibronectin, vitronectin, laminin, and collagen type IV adhesion to poly(methyl methacrylate) (PMMA), silicone, hydrophobic soft acrylate, and hydrogel intraocular lenses (IOLs) in pseudophakic human autopsy eyes. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Thirty-eight autopsy eyes containing PMMA, silicone, hydrophobic acrylate, or hydrogel IOLs were assessed. Histological sections were prepared from each eye, and immunohistochemical analyses were performed for fibronectin, vitronectin, laminin, and collagen type IV. One hundred fifty-two specimens were analyzed. RESULTS: A sandwich-like structure (anterior or posterior capsule/fibronectin/1 cell layer/fibronectin/IOL surface) was seen in 12 of 14 autopsy eyes with soft acrylate IOLs, 3 of 10 with a PMMA IOL (P =.0094), 1 of 10 with a silicone IOL (P =.0022), and 0 of 4 with a hydrogel IOL (P =. 0041). The thicker fibrocellular tissue on the inner surface of the anterior or posterior capsule that was in contact with silicone IOLs was lined with collagen type IV. Vitronectin and laminin were not found at the fibrocellular tissue-IOL interface in any specimen. CONCLUSIONS: This study seems to confirm the sandwich theory of posterior capsule opacification in eyes with an IOL and suggests that fibronectin may be the major extracellular protein responsible for the attachment of hydrophobic soft acrylate (AcrySof(R)) IOLs to the capsular bag. This may represent a true bioactive bond between the IOL and lens epithelial cells or between the IOL and the capsular bag and may be one reason the PCO and neodymium:YAG capsulotomy rates are lower in eyes with a soft acrylate IOL.

Biocompatible Materials↗
PubMed2000

Surgical prevention of posterior capsule opacification. Part 3: Intraocular lens optic barrier effect as a second line of defense.

PURPOSE: To emphasize an important aspect of preventing posterior capsule opacification (PCO), the barrier effect established by the optic of a posterior chamber intraocular lens (PC IOL), and present a new classification regarding capsular bag status after extra-capsular cataract extraction, including phacoemulsification. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: This analysis included 150 consecutive eyes obtained postmortem with United States-manufactured PC IOLs including (1) poly(methyl methacrylate), (2) silicone, and (3) hydrophobic acrylic designs that were accessioned in the Center from September 1995 to January 1, 1998. Gross photographs from behind (Miyake-Apple views) were taken and serial histologic sections prepared. RESULTS: Microscopic analysis of the 150 eyes showed that the morphologic appearance of the capsular bag could be grouped into 2 categories: (1) those with little or no evidence of retained cortical material and cells, and (2) those with retained cortical material and cells in which a Soemmering's ring formed. With the latter, when a distinct barricade to cellular migration created by the IOL optic was noted, 2 discrete configurations occurred, depending on the different geometries of the optic components. With a classic biconvex optic with a curved and tapered edge, in many instances some ingrowth of cells proceeded posteriorly around the edge of the IOL optic in the direction of the central axis. With a lens optic that had a squared, truncated, and relatively thick edge, there was often abrupt termination of cells at the peripheral edge of the optic. The posterior capsule subtending the entire optic zone was therefore relatively or totally cell free. CONCLUSIONS: The barrier effect of the IOL optic appears to be of critical importance in retarding ingrowth of cells, functioning as a second line of defense when cortical cleanup is incomplete. Analysis of PC IOLs obtained postmortem showed that a square, truncated optic edge seemed to provide the maximum impediment to cell growth behind the IOL optic.

Acrylic Resins↗
PubMed2000

Surgical prevention of posterior capsule opacification. Part 1: Progress in eliminating this complication of cataract surgery.

PURPOSE: To evaluate over almost 2 decades the success of a component of cataract surgery that represents a critical step in reducing the incidence of posterior capsule opacification (PCO); namely, the efficacy of cortical cleanup. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Accessioned from the early 1980s to 1997, 3320 eyes obtained postmortem with posterior chamber intraocular lenses were analyzed with respect to formation of a postoperative Soemmering's ring. This anatomic lesion, the precursor of clinical PCO, represents an important and measurable indication of the quality of cortical cleanup. Its formation was documented using Miyake-Apple posterior photographic analysis. RESULTS: The quality and thoroughness of cortical cleanup and overall effectiveness in eliminating retained and/or regenerating cortical cells, as measured by scoring of Soemmering's rings, showed virtually no net change since the early 1980s. The intensity of Soemmering's ring was higher in the most recent specimens than in those in the early 1980s. CONCLUSION: The results indicate that renewed attention to cortical cleanup in cataract surgery is warranted for significant reduction in incidence or the elimination of PCO. More attention to the hydrodissection (cortical cleaving hydrodissection) step of the procedure is likely a practical, immediately implementable, and inexpensive remedy.

Cadaver↗
PubMed2000

Surgical prevention of posterior capsule opacification. Part 2: Enhancement of cortical cleanup by focusing on hydrodissection.

PURPOSE: To experimentally analyze the role and efficacy of hydrodissection in achieving maximal cortical cleanup. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Phacoemulsification and irrigation/aspiration were performed in 10 pairs of human eyes (20 eyes) obtained postmortem. Ten eyes had previous hydrodissection and 10 eyes, no hydrodissection. The time (seconds) required for complete lens substance removal in each procedure was measured. In addition, a qualitative evaluation of difficulty of surgery was noted. RESULTS: Phacoemulsification required 28.6% less time in eyes with previous hydrodissection than in those without. Irrigation/aspiration time was reduced by 50.9% when hydrodissection was performed. The total time of each procedure required for complete evacuation of the capsular bag was reduced by an average of 37.7% in eyes with hydrodissection. Furthermore, qualitatively the procedure was far easier, less stressful, and caused less posterior capsule stress or rupture when copious hydrodissection was performed. CONCLUSIONS: Hydrodissection enhances the general safety and efficiency of cortical cleanup, especially at 12 o'clock. Hydrodissection is the best available, practical, immediately implementable, and inexpensive means to help remove equatorial E-cells and thus alleviate the incidence of posterior capsule opacification.

Aged↗
PubMed2000

Creating cataracts of varying hardness to practice extracapsular cataract extraction and phacoemulsification(2).

We describe a method to harden the nucleus of crystalline lenses in postmortem human globes by intralenticular injection of a mixture of paraformaldehyde and glutaraldehyde (Karnovsky's solution). Evaluation of the nuclear manipulations, using the Miyake-Apple posterior video/photographic technique, shows that the method provides suitable specimens for practicing extracapsular cataract extraction and phacoemulsification.

Cataract↗
PubMed2000

Interlenticular opacification: clinicopathological correlation of a complication of posterior chamber piggyback intraocular lenses.

PURPOSE: To present a clinicopathological correlation of 2 pairs of piggyback posterior chamber intraocular lenses (PC IOLs) explanted because of opacification between the lens optics. SETTING: Gayton Health Center, Eyesight Associates of Middle Georgia, Warner Robins, Georgia, and Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Two pairs of piggyback AcrySof lenses were explanted from 2 patients with significant visual loss related to opacification between the optics. They were submitted for pathological analysis. Gross and histopathological examinations were performed, and photomicroscopy was used to document the results. RESULTS: Gross examination showed accumulation of a membrane-like white material between the lenses. Histopathological examination revealed that the tissue consisted of retained/proliferative lens epithelial cells (bladder cells or pearls) mixed with lens cortical material. CONCLUSION: Piggyback PC IOLs were explanted in 2 cases because of a newly described complication, interlenticular opacification. Three surgical means may help prevent this complication: meticulous cortical cleanup, especially in the equatorial region; creation of a relatively large continuous curvilinear capsulorhexis to sequester retained cells peripheral to the IOL optic within the equatorial fornix; insertion of the posterior IOL in the capsular bag and the anterior IOL in the ciliary sulcus to isolate retained cells from the interlenticular space.

Acrylic Resins↗
PubMed1999

Evaluation of teflon-coated intraocular lenses in an organ culture method.

An amorphous and transparent form of Teflon is proposed as a coating of polymethylmethacrylate (PMMA) intraocular lenses (IOLs), rendering them highly hydrophobic. We used an organ culture method to evaluate cell adhesion, proliferation, and migration on Teflon-coated IOLs. Corneal explants from 14-day-old chicken embryos were placed on a semisolid culture medium and covered with uncoated PMMA (n = 36) and Teflon-coated PMMA (n = 36) IOLs and two controls, Thermanox (n = 84) and latex (n = 36). After incubation (7 days at 37 degrees C), a digital imaging system was used to measure the areas of the cell migration layers on the materials. The cells were then removed with tripsin-ethylenediaminetetraacetic acid and the cells detached at times up to 75 min were counted (Coulter(R) Multisizer System). The values were used to construct a cell disconnecting curve for each material. The areas of cell migration layers on uncoated and Teflon-coated IOLs were significantly different (p <.05). Cell disconnecting curves demonstrated that cells adhered less strongly to Teflon-coated IOLs than to the other materials. This organ culture method demonstrated that the coating of PMMA IOLs with Teflon AF(R) is correlated with antiadhesive and antiproliferative properties.

Animals↗
PubMed1999

Neutral red assay of the cytotoxicity of fluorocarbon-coated polymethylmethacrylate intraocular lenses in vitro.

Polymethylmethacrylate (PMMA) intraocular lenses (IOLs) were coated with Teflon AF, an amorphous, transparent Teflon, to render them highly hydrophobic. Teflon-coated PMMA IOLs were immersed in culture medium for 30 days at 37 degrees C. Four concentrations of the IOL leachables, 2 concentrations of a toxic control (phenol), and complete liquid culture medium (nontoxic control) were incubated for 24 h in a 96-well plate containing confluent L-929 fibroblasts. The cytotoxic effect of each solution on the fibroblasts was quantitatively assessed by measuring the uptake of neutral red by the viable cells. After the extraction of the neutral red using 1% acetic acid-50% ethanol, the optical densities were measured with a microplate reader at 550 nm. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to analyze the surfaces of the IOLs. Only the optical densities in the wells containing fibroblasts that had been in contact with the phenol solutions were significantly lower than those in the wells incubated with the nontoxic control solution (p < 0.01). There were no signs of surface alteration by SEM, apart from some crystals on the IOLs. The crystals were composed of Na and Cl, as demonstrated by XPS. Aqueous extractables from the Teflon-coated IOLs produced no cytotoxic effects in the neutral red assay used.

Animals↗
PubMed1999

Confocal microscopy in Bowman and stromal corneal dystrophies.

OBJECTIVE: To use confocal microscopy to demonstrate the similarity among three autosomal-dominant corneal dystrophies and the diversity of the deposit patterns within a single dystrophy. DESIGN: A prospective, comparative case series. PARTICIPANTS: Twenty patients (40 eyes) from 10 families suffering from Bowman or stromal dystrophy agreed to take part: 3 with Reis-Bückler dystrophy, 12 with granular dystrophy, and 5 with lattice type-I dystrophy. Of these, nine had recurrence in their grafts or after phototherapeutic keratectomy before the confocal examination. The confocal images of affected corneas were compared with those of ten normal control eyes (ten subjects). INTERVENTION: All patients were examined by slit-lamp biomicroscopy. Confocal microscopy was performed with Achroplan 40x/numeric aperture (NA) = 0.75 and 63x/NA = 0.9 water immersion objectives. Image analysis was used to identify the corneal epithelial and stromal deposits correlated with each disorder. MAIN OUTCOMES MEASURES: Selected images of the corneal layers were evaluated qualitatively for the size, shape, light scattering, and reflection of the deposits. RESULTS: Slit-lamp biomicroscopy showed stromal involvement in all affected eyes. Confocal microscopy identified epithelial deposits in 30% of the eyes and stromal deposits in all eyes. The deposits within the epithelium were revealed more clearly with the 63x/NA = 0.9 objective (higher numeric aperture). Some of the confocal findings near the Bowman layer were common for all three dystrophies. Normal control eyes showed no epithelial or stromal deposits, either by biomicroscopy or confocal microscopy. CONCLUSIONS: Confocal microscopy provides an in vivo evaluation of the deposits in the cornea, with a higher resolution than biomicroscopy. The confocal findings common to the three dystrophies may agree with previous hypotheses of the same genetic origin. It may be a useful adjunct to slit-lamp biomicroscopy, particularly when histopathologic studies cannot be performed.

Adolescent↗
PubMed1999

Visual results and postoperative complications of capsular bag and ciliary sulcus fixation of posterior chamber intraocular lenses in children with traumatic cataracts.

PURPOSE: To evaluate the visual results and postoperative complications of capsular bag and ciliary sulcus fixation of posterior chamber intraocular lenses (IOLs) for traumatic cataracts in children. SETTING: Department of Ophthalmology, Postgraduate Institute of Medical Education and Research, Chandigarh, India. METHODS: Twenty children (20 eyes) with traumatic cataracts had extracapsular cataract extraction (ECCE) and posterior chamber IOL implantation. They were randomly divided into 2 groups. Capsular bag fixation was performed in 10 children (Group A) and ciliary sulcus fixation in the other 10 (Group B). Traumatic cataracts associated with large corneal lacerations (10.0 mm or more), hyphema, angle recession, or posterior segment involvement were excluded. The best corrected visual acuity (BCVA) as well as early and delayed postoperative complications were prospectively evaluated in both groups. RESULTS: The BCVA was 6/12 or better in 9 eyes (90%) in Group A and 8 eyes (80%) in Group B at the end of the mean follow-up (24.6 months +/- 10.6 [SD]). Amblyopia (1 eye in Group A) and corneal scar and commotio retinae (1 eye each in Group B) accounted for a visual acuity of worse than 6/12. The residual refractive error did not exceed 3.50 diopters in either group. The incidences of fibrinous anterior uveitis and pupillary capture were significantly higher in Group B (P < .05, Fisher exact test). CONCLUSION: Capsular bag fixation of posterior chamber IOLs provided visual results similar to those with ciliary sulcus fixation but was associated with fewer postoperative complications, particularly uveitis and pupillary capture. This represents another important reason to attempt in-the-bag fixation in cases of traumatic cataract.

Cataract↗