Compositional Analysis of Extracellular Aggregates in the Eyes of Patients With Exfoliation Syndrome and Exfoliation Glaucoma.

Purpose: Exfoliation syndrome (XFS) is a condition characterized by the production of insoluble fibrillar aggregates (exfoliation material; XFM) in the eye and elsewhere. Many patients with XFS progress to exfoliation glaucoma (XFG), a significant cause of global blindness. We used quantitative mass spectrometry to analyze the composition of XFM in lens capsule specimens and in aqueous humor (AH) samples from patients with XFS, patients with XFG and unaffected individuals. Methods: Pieces of lens capsule and samples of AH were obtained with consent from patients undergoing cataract surgery. Tryptic digests of capsule or AH were analyzed by high-performance liquid chromatography-mass spectrometry and relative differences between samples were quantified using the tandem mass tag technique. The distribution of XFM on the capsular surface was visualized by SEM and super-resolution light microscopy. Results: A small set of proteins was consistently upregulated in capsule samples from patients with XFS and patients with XFG, including microfibril components fibrillin-1, latent transforming growth factor-ß-binding protein-2 and latent transforming growth factor-ß-binding protein-3. Lysyl oxidase-like 1, a cross-linking enzyme associated with XFS in genetic studies, was an abundant XFM constituent. Ligands of the transforming growth factor-ß superfamily were prominent, including LEFTY2, a protein best known for its role in establishing the embryonic body axis. Elevated levels of LEFTY2 were also detected in AH from patients with XFG, a finding confirmed subsequently by ELISA. Conclusions: This analysis verified the presence of suspected XFM proteins and identified novel components. Quantitative comparisons between patient samples revealed a consistent XFM proteome characterized by strong expression of fibrillin-1, lysyl oxidase-like-1, and LEFTY2. Elevated levels of LEFTY2 in the AH of patients with XFG may serve as a biomarker for the disease.

Pseudoexfoliation syndrome in diabetic patients: transmission electron microscopy study of anterior lens epithelial cells.

Purpose: to examine the lens epithelial cells in diabetic patients with pseudoexfoliation to ultramicroscope and to compare the findings with those of patients without diabetes mellitus (DM) and/or without pseudoexfoliation (PEX). Materials and Methods: Forty patients aged 65-86 years were enrolled in the study. All patients had senile cataract and were divided into four groups of ten patients in each group. Group I: patients without pseudoexfoliation, without DM, Group II: without pseudoexfoliation, with DM, Group III: with pseudoexfoliation, without DM, Group IV (Pseudoexfoliation-Diabetic Group): with pseudoexfoliation, with DM. In all cases, part of the central portion of anterior lens capsule was removed during routine cataract surgery, and was properly prepared in order to be examined under a transmission electron microscope. Results: In the control group, mainly degenerative alterations to varying extents were observed. In all groups, intracellular and extracellular oedema, multilayering, apoptosis, completely destroyed cells adjacent to normal cellswere described. In the diabetic group, alterations were more severe with respect to group I. In PEX cases, the additionalirregularity of the epithelium surface, loose intercellular connection, as well as the loose connection between cells and basement membrane were described with the presence of PEX material free and within the basement membrane. In cases with PEX and DM, degenerative alterations and PEX material were observed as well, but the epithelium was better conserved compared to the PEX group. Conclusion: the observed lesions were more extended and more frequent in the pseudoexfoliation group, followed by the diabetic group. The pseudoexfoliation-diabetic group presented less intense modifications raising questions about the interaction of these different diseases. Abbreviations: DM = Diabetes Mellitus, PEX = Pseudoexfoliation, PXM = Pseudoexfoliative Material, AD = Alzheimer disease, TGF-ß1 = Transforming Growth Factor beta 1, WHO = World Health Organization, LEC = Lens Epithelium Cells, BM = Basement Membrane, CM = Cytoplasmic Membrane.

BILATERAL ENTEROCOCCUS FAECALIS ENDOPHTHALMITIS WITH MULTIPLE RECURRENCES.

PURPOSE: To describe the first case report of a bilateral recurrent Enterococcus faecalis endophthalmitis postcataract surgery. METHODS: Case report with a description of the timeline, diagnosis, and management of a patient with bilateral recurrent E. faecalis endophthalmitis. RESULTS: An 89-year-old man presented 6 weeks' postcataract surgery with pain, tearing, and blurred vision in the left eye. B-scan ultrasonography revealed vitritis and cultures postvitrectomy grew E. faecalis. There was gradual improvement in vision postintravitreal vancomycin administration. Four years later, the patient experienced another episode of E. faecalis endophthalmitis in the right eye postcataract extraction, followed by several additional episodes in both eyes posttreatment. CONCLUSION: Enterococcus faecalis is a rare but highly virulent cause of endophthalmitis that may remain sequestered in the capsular bag, despite aggressive treatment. Even after recurrent episodes, early vitrectomy and aggressive antibiotic therapy may prove to be effective in preventing vision loss.

Ultrastructural Analysis of the Anterior Lens Epithelium in Cataracts Associated with Uveitis.

PURPOSE: To investigate the transmission electron microscopic findings of lens epithelial cells (LECs) in patients with different subtypes of uveitis and to compare the findings with those in age-matched controls. METHODS: In this prospective case-control study, the anterior lens capsules were taken from 47 eyes of 47 patients with uveitis of different subtypes (17 with Fuchs uveitis syndrome [FUS], 13 with -Behçet's uveitis, 10 with idiopathic uveitis, and 7 with herpetic keratouveitis) and from 15 eyes of 15 control patients. RESULTS: In the FUS group, the LECs had homogeneous thickening and irregularity, with some small vacuoles and widespread, oval-shaped pigment clusters in some areas. In the Behçet uveitis group, there was evident thinning in the lens epithelium. The subepithelial tissue under the epithelium was thickened, and edematous areas were detected. In the idiopathic uveitis group, the LECs were thinner with small vacuoles, and the cubic structure of the LECs was transformed into a squamous one. Moreover, the LECs included some small vacuoles, similar to those in the FUS group. In the herpetic keratouveitis group, two prominent cell types were observed: (1) completely normal LECs and (2) degenerated-type LECs with pyknotic nuclei, condensation of chromatin, swelling in the cytoplasm, membrane ruptures, and intra-cytoplasmic inclusion bodies. In the control group, the LECs and all of their elements occurred in normal ultrastructural patterns, with the exception of a few small intraepithelial vacuoles, which were fewer in number and smaller than those in the FUS and idiopathic uveitis groups. CONCLUSION: The electron microscopic analysis of LECs of patients with different subtypes of uveitis revealed significant ultrastructural alterations, which may be related to the summation of oxidative stress and intraocular inflammation.

The ultrastructural alterations in the lens capsule and epithelium in eyes with traumatic white cataract.

PURPOSE: To demonstrate the morphological and physiological characteristics of lens epithelial cells (LECs) in patients with traumatic cataract using transmission electron microscopy (TEM) to further understand penetrating ocular injury-induced cataract morphology and epithelial repair mechanisms involved at a cellular level. METHODS: This is a prospective international study. Sixteen eyes of 16 consecutive patients who were diagnosed as traumatic white cataracts following the anterior lens capsule perforation and 13 eyes of 13 patients with idiopathic posterior subcapsular cataract were included to the study. The anterior lens capsules (aLCs: basement membrane and associated LECs) were obtained from cataract surgery and prepared for TEM. RESULTS: Two prominent cell types were observed in all aLCs of the traumatic cases: degenerated type LECs having variable sized intraepithelial vacuoles close to injury site and normal appearing LECs having an euchromatic nucleus distant from the injury site. In control group, the LECs and all their elements were in normal ultrastructural pattern except some small intraepithelial vacuoles, which were fewer and smaller than the vacuoles in the degenerated LECs of the traumatic group. CONCLUSIONS: The ultrastructural findings of our cases support that traumatically induced dysfunction of the lens epithelium may lead to an edema in superficial cortical lens fibers that subsequently undergo degeneration and produce a localized zone of vacuolization.

Electron microscopic evaluation of anterior lens epithelium in patients with idiopathic congenital cataract.

PURPOSE: To investigate the ultrastructure of the lens epithelial cells (LECs) in patients with idiopathic congenital cataract. METHODS: This is a prospective interventional study. The anterior lens capsules (aLC: basement membrane and associated LECs) were taken from 16 eyes of 12 consecutive patients who were diagnosed as having idiopathic congenital cataracts. The aLCs were obtained from cataract surgery and prepared for transmission electron microscopy (TEM). RESULTS: Some significant ultrastructural changes were observed in all aLCs of the participants. The anterior LECs showed alterations in different areas which were partly cuboidal and partly squamous in shape. The LECs had euchromatic nucleus and included some vacuoles in the cytoplasms as a remarkable alteration. The sizes of these intraepithelial cell vacuoles were changeable. CONCLUSIONS: We identified remarkable changes in LECs of the eyes with idiopathic congenital cataract by TEM. It can be assumed that oxidative damage may be associated with these ultrastructural changes in LECs of the eyes with idiopathic congenital cataracts.

Analysis of Intraocular Lens Biofilms and Fluids After Long-Term Uncomplicated Cataract Surgery.

PURPOSE: Postoperative endophthalmitis is a potentially sight-threatening complication of cataract surgery. However, the pathophysiological mechanisms are not completely understood. We sought to study and evaluate the intraocular environment (aqueous and vitreous humors), the capsular tissue, and the intraocular lens (IOL) surfaces of normal eyes after long-term uncomplicated cataract surgery. DESIGN: Experimental laboratory investigation. METHODS: We studied 69 eyes donated for transplantation that had previously undergone cataract surgery with posterior chamber IOL implantation and that had no recorded clinical history of postoperative inflammation. We assessed the intraocular environment (DNA traces and biofilm formation) by microbiological evaluation of intraocular fluids using conventional microbiology and molecular techniques, including assessment for the presence of microbes (biofilm formation) on the IOL surface by scanning electron microscopy and ultrastructural capsular remnants by transmission electron microscopy. RESULTS: Isolated or aggregated cocci were probable in 18.8% of IOL optic surfaces (n = 13) studied by scanning electron microscopy, suggesting the presence of bacterial biofilm. In 3 intraocular fluid samples for IOLs with biofilm, we identified 16S rDNA by polymerase chain reaction and sequencing. No microbial contamination was found in intraocular fluids by conventional microbiological methods. CONCLUSIONS: Our data suggest the possibility of bacterial biofilm formation on the optic surface of IOLs in normal eyes after long-term uncomplicated cataract surgery even in the absence of clinical or subclinical symptoms.

Femtosecond laser-assisted cataract surgery in Alport syndrome with anterior lenticonus.

PURPOSE: To report the surgical treatment of 3 eyes of 2 patients with bilateral anterior lenticonus due to Alport syndrome using femtosecond laser-assisted cataract surgery (FLACS). METHODS: Two patients with Alport syndrome presented to our department due to anterior lenticonus in both eyes. We performed FLACS with posterior chamber lens implantation in both eyes of one patient and in one eye of the other patient. Anterior segment morphologic changes were visualized with a Scheimpflug camera, and anterior segment optical coherence tomography preoperatively and 3 months after surgery. Ultrastructure of the cut capsule edges was observed with scanning electron microscopy and compared to the edge of femtosecond laser capsulotomy performed on an otherwise healthy patient with cataract (control). RESULTS: The intraocular lens (IOL) postoperative positioning parameters met the international requirements of aspherical and wavefront customized IOLs (tilt <10 degree, decentration <800 µm). Scanning electron microscopy revealed the same characteristics of the cut capsule edges in the Alport and in the control eyes. CONCLUSIONS: Femtosecond laser cataract surgery can be a safe and successful method for optical rehabilitation of anterior lenticonus in patients with Alport syndrome.

A gradient of matrix-bound FGF-2 and perlecan is available to lens epithelial cells.

Fibroblast growth factors play a key role in regulating lens epithelial cell proliferation and differentiation via an anteroposterior gradient that exists between the aqueous and vitreous humours. FGF-2 is the most important for lens epithelial cell proliferation and differentiation. It has been proposed that the presentation of FGF-2 to the lens epithelial cells involves the lens capsule as a source of matrix-bound FGF-2. Here we used immunogold labelling to measure the matrix-bound FGF-2 gradient on the inner surface of the lens capsule in flat-mounted preparations to visualize the FGF-2 available to lens epithelial cells. We also correlated FGF-2 levels with levels of its matrix-binding partner perlecan, a heparan sulphate proteoglycan (HSPG) and found the levels of both to be highest at the lens equator. These also coincided with increased levels of phosphorylated extracellular signal-regulated kinase 1 and 2 (pERK1/2) in lens epithelial cells that localised to condensed chromosomes of epithelial cells that were Ki-67 positive. The gradient of matrix-bound FGF-2 (anterior pole: 3.7 ± 1.3 particles/µm2; equator: 8.2 ± 1.9 particles/µm2; posterior pole: 4 ± 0.9 particles/µm2) and perlecan (anterior pole: 2.1 ± 0.4 particles/µm2; equator: 5 ± 2 particles/µm2; posterior pole: 1.9 ± 0.7 particles/µm2) available at the inner lens capsule surface was measured for the bovine lens. These data support the anteroposterior gradient hypothesis and provide the first measurement of the gradient for an important morphogen and its HSPG partner, perlecan, at the epithelial cell-lens capsule interface.

Occurrence of capsular delamination in the dislocated in-the-bag intraocular lens.

PURPOSE: To examine the lens capsules of dislocated in-the-bag IOLs. METHODS: Retrospective case series. Nineteen dislocated IOLs encased in capsules (in-the-bag IOLs) from 19 patients were included. The clinical characteristics of the 19 patients were reviewed. The explanted in-the- bag IOLs were examined by scanning electron microscopy. RESULTS: Associated clinical conditions included pseudoexfoliation (PEX) in seven eyes, high myopia in three eyes, previous history of trauma in two eyes, previous vitreoretinal surgery in two eyes, retinitis pigmentosa in one eye and uveitis in one eye. PEX specimens showed capsular contraction, shrinkage of the diameter of the capsular bag and dehiscence of zonular fibers. The remaining 12 specimens exhibited slight capsular contraction that lacked shrinkage of the bag and exhibited capsular delamination at the equatorial region, in which the zonular fibers had completely disappeared. CONCLUSION: Capsular delamination as well as dehiscence of zonular fibers may be involved in the dislocation of in-the-bag IOLs.

Trypan blue staining for capsulorhexis: ultrastructural effect on lens epithelial cells and capsules.

PURPOSE: To evaluate the ultrastructural effect of trypan blue 0.1% staining for capsulorhexis on lens epithelial cells (LECs) and capsules. SETTING: Division of Ophthalmology, University of São Paulo, São Paulo, Brazil. METHODS: Before capsulorhexis, patients were randomly assigned to 1 of 2 groups. Trypan blue 0.1% staining was performed in the treatment group. No trypan blue was used in the control group. Samples of capsules with LECs were fixed and analyzed with routine optical microscopy techniques, immunohistochemistry for beclin-1 expression (a marker of autophagy), terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling to detect apoptosis, and transmission electron microscopy (TEM). Morphometric analyses were performed, and the 2 sets of data were compared. RESULTS: Each group comprised 15 patients. Cell death by autophagy and apoptosis was observed in the treatment group but not in the control group. The TEM images of subcapsular epithelium cells showed mitochondrial rupture, dilation of the cisterns of the endoplasmic reticulum, increased cytoplasmic and nuclear electron density, and abnormalities in the nuclear profile of trypan blue-stained cells. Morphometric analysis showed statistically significant differences between the 2 groups in the longest nuclear axes and the ratio between the total nuclear perimeter and the cell area (P = .03). The difference in capsule thickness between groups was not significant. CONCLUSION: Trypan blue caused LEC death, which supports the hypothesis that staining with trypan blue 0.1% can help reduce the incidence of posterior capsule opacification after cataract surgery. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Anterior capsulotomy with a pulsed-electron avalanche knife.

PURPOSE: To evaluate a new pulsed-electron avalanche knife design for creating a continuous curvilinear capsulotomy (CCC) and compare the CCC with a mechanical capsulorhexis. SETTING: Department of Ophthalmology, Stanford University, Stanford, California, USA. METHODS: In this study, CCCs were created in freshly enucleated bovine eyes and in rabbit eyes in vivo. The cutting velocity was adjusted by controlling the burst repetition rate, voltage amplitude, and burst duration. Tissue samples were fixed and processed for histology and scanning electron microscopy (SEM) immediately after surgery. RESULTS: The study included 50 bovine eyes and 10 rabbit eyes. By adjusting the electrosurgical waveforms, gas-bubble formation was minimized to permit good surgical visualization. The optimum voltage level was determined to be +/-410 V with a burst duration of 20 mus. Burst repetition rate, continuously adjustable from 20 to 200 Hz with footpedal control, allowed the surgeon to vary linear cutting velocity up to 2.0 mm/s. Histology and SEM showed that the pulsed-electron avalanche knife produced sharp-edged capsule cutting without radial nicks or tears. CONCLUSIONS: The probe of the pulsed-electron avalanche knife duplicated the surgical feel of a 25-gauge cystotome and created a histologically smooth capsule cut. It may improve precision and reproducibility of creating a CCC, as well as improve its proper sizing and centration, especially in the face of surgical risk factors, such as weak zonules or poor visibility. FINANCIAL DISCLOSURES: Drs. Palanker and Vankov hold patents to the pulsed electron avalanche knife technology, which are licensed to PEAK Surgical by Stanford University. Drs. Palanker and Chang are consultants to PEAK Surgical. Dr. Vankov is an employee of PEAK Surgical. Neither of the other authors has a financial or proprietary interest in any material or method mentioned.

Initial clinical evaluation of an intraocular femtosecond laser in cataract surgery.

PURPOSE: To evaluate femtosecond laser lens fragmentation and anterior capsulotomy in cataract surgery. METHODS: Anterior capsulotomy and phacofragmentation procedures performed with an intraocular femtosecond laser (LenSx Lasers Inc) were initially evaluated in ex vivo porcine eyes. These procedures were then performed in an initial series of nine patients undergoing cataract surgery. In addition to standard intraoperative assessments (including capsulotomy diameter accuracy and reproducibility), optical coherence tomography was used to evaluate human procedures. RESULTS: For an intended 5-mm capsulorrhexis in porcine eyes, average achieved diameters were 5.88+/-0.73 mm using a standard manual technique and 5.02+/-0.04 mm using the femtosecond laser. Scanning electron microscopy revealed equally smooth cut edges of the capsulotomy with the femtosecond laser and manual technique. Compared to control porcine eyes, femtosecond laser phacofragmentation resulted in a 43% reduction in phacoemulsification power and a 51% decrease in phacoemulsification time. In a small series of human clinical procedures, femtosecond laser capsulotomies and phacofragmentation demonstrated similarly high levels of accuracy and effectiveness, with no operative complications. CONCLUSIONS: Initial results with an intraocular femtosecond laser demonstrate higher precision of capsulorrhexis and reduced phacoemulsification power in porcine and human eyes.

Cataracta ossea - Ultrastructural and specimen analysis.

BACKGROUND: Although intraocular osseous metaplasia is a well-known phenomenon, ossification of the lens is a rare phenomenon nowadays. MATERIAL AND METHODS: An enucleated phthisical eye showed a rock-hard intraocular particle. Lens status after a trauma 36 years ago had been unclear. Differential diagnosis included an intraocular foreign body or ossification of the lens. X-ray diffraction analysis showed microcrystalline apatite indicating a mineralized structure. Histologic specimens revealed a mineralized lens that underwent secondary osseous metaplasia. CONCLUSIONS: Due to the small number of cases, the mechanisms and preconditions of osseous metaplasia of the lens are not understood in detail, but injury to the lens capsule and availability of blood supply are being discussed. Both were present in this case, in which the luxated lens ended up in the ciliary body region. The mechanism resembled enchondral ossification rather than intramembranous ossification, which is seen in osseous metaplasia of other intraocular structures.

AlphaA-crystallin R49Cneo mutation influences the architecture of lens fiber cell membranes and causes posterior and nuclear cataracts in mice.

BACKGROUND: AlphaA-crystallin (CRYAA/HSPB4), a major component of all vertebrate eye lenses, is a small heat shock protein responsible for maintaining lens transparency. The R49C mutation in the alphaA-crystallin protein is linked with non-syndromic, hereditary human cataracts in a four-generation Caucasian family. METHODS: This study describes a mouse cataract model generated by insertion of a neomycin-resistant (neor) gene into an intron of the gene encoding mutant R49C alphaA-crystallin. Mice carrying the neor gene and wild-type Cryaa were also generated as controls. Heterozygous knock-in mice containing one wild type gene and one mutated gene for alphaA-crystallin (WT/R49Cneo) and homozygous knock-in mice containing two mutated genes (R49Cneo/R49Cneo) were compared. RESULTS: By 3 weeks, WT/R49Cneo mice exhibited large vacuoles in the cortical region 100 mum from the lens surface, and by 3 months posterior and nuclear cataracts had developed. WT/R49Cneo mice demonstrated severe posterior cataracts at 9 months of age, with considerable posterior nuclear migration evident in histological sections. R49Cneo/R49Cneo mice demonstrated nearly complete lens opacities by 5 months of age. In contrast, R49C mice in which the neor gene was deleted by breeding with CreEIIa mice developed lens abnormalities at birth, suggesting that the neor gene may suppress expression of mutant R49C alphaA-crystallin protein. CONCLUSION: It is apparent that modification of membrane and cell-cell interactions occurs in the presence of the alphaA-crystallin mutation and rapidly leads to lens cell pathology in vivo.

Radial extension of capsulorhexis in true exfoliation patient: a potentially hazardous complication.

A 77-year-old woman presented with decreased visual acuity due to cataracts. True exfoliation of the lens capsule was detected in both eyes, and phacoemulsification cataract surgery with intraocular lens implantation was performed in the right eye. Before the continuous curvilinear capsulorhexis was started, indocyanine green dye was introduced into the anterior chamber; when the forceps was used during the capsulorhexis, the superficial layer of the lens capsule separated from the deep layer and induced an impending radial extension. We believe this is the first such case to be reported.

Transmission electron microscopy of the rabbit posterior capsule irrigated with thapsigargin and 5-fluorouracil in a sealed-capsule irrigation device.

PURPOSE: To investigate, by transmission electron microscopy (TEM), the effect on the posterior capsule of a young rabbit eye of 5-fluorouracil (5-FU) or thapsigargin in a sealed-capsule irrigation device. SETTING: St Erik's Eye Hospital, Stockholm, Sweden. METHODS: Clear lens extraction was performed unilaterally in eight 4-week-old rabbits. A sealed-capsule irrigation device was irrigated for 2 min with 20 ml of one of the following: balanced salt solution (BSS; n=2), thapsigargin 300 muM (n=2), 5-FU 50 mg/ml (n=2), or 5-FU 25 mg/ml (n=2). The substances were washed out for 10 s with BSS. The eyes were left aphakic. Six weeks postoperatively, the animals were killed, and the posterior capsule was extracted and fixed for TEM. As a control, we also evaluated the capsules from the two fellow eyes in the BSS group that did not undergo surgery. RESULTS: The ultrastructure of the posterior capsule in eyes irrigated with 5-FU or thapsigargin did not differ from that in the eyes irrigated with BSS or in the eyes that did not have surgery. The membranes had the same ultrastructure with thin collagen fibres on the anterior and posterior face of the posterior capsule and an amorphic matrix. CONCLUSION: Thapsigargin or 5-FU used in a sealed-capsule irrigation device does not seem to harm the posterior capsule, which appeared similar to when the capsule is irrigated with BSS.

In vitro femtosecond laser-assisted nanosurgery of porcine posterior capsule.

PURPOSE: To investigate femtosecond laser-assisted nanosurgery of the posterior capsule in a prospective in vitro animal study. SETTING: Department of Ophthalmology and Eye Hospital, University of Saarland, Homburg, and Fraunhofer Institute for Biomedical Engineering, St. Ingbert, Germany. METHODS: The posterior capsules of 12 porcine eyes were irradiated with a nonamplified 90 MHz near-infrared 750 nm titanium:sapphire femtosecond laser. Intratissue and superficial laser cuts of laser-ablated (5 capsules) and control (1 capsule) specimens were examined by femtosecond multiphoton laser scanning microscopy (MLSM) and transmission electron microscopy (TEM). RESULTS: Laser exposure time and pulse power determined the width of the lesions, which ranged from 0.69 microm+/-0.19 (SD) to 2.81+/-0.5 microm. Both MLSM and TEM revealed minimal collateral alterations in the tissue surrounding the laser cuts. CONCLUSIONS: Nonamplified near-infrared femtosecond laser pulses at low pulse energies may be a promising strategy for precise lamellar noncontact nanosurgery of the posterior capsule, with minimal structural collateral damage to surrounding tissue. High-resolution MLSM offers 3-dimensional, noninvasive, nondestructive imaging at submicrometer resolution within seconds before and after ablation.

Generation of transparency and cellular organization in lens explants.

The lens grows via the proliferation and differentiation of lens epithelial cells into lens fibres. This differentiation process, thought to be controlled by factors present in the vitreous fluid, generates tightly-packed, parallel-aligned fibre cells that confer transparency to the lens. Using lens epithelial-cell explants we examined how explant orientation and growth factor treatment can affect cellular arrangement and explant transparency. Fibre cell differentiation was induced in lens explants by culturing cells with fibroblast growth factor (FGF) or bovine vitreous. Cell shape and arrangement was investigated using confocal microscopy, electron microscopy, immunofluorescence and in situ hybridization. Explant transparency was measured using light microscopy. Confocal microscopy demonstrated that explant orientation determined cellular arrangement, irrespective of the differentiation stimuli used. In explants where epithelial cells were confined between their normal basement membrane (the lens capsule) and the base of the culture dish, the cells became elongated, thin and parallel-aligned. In contrast, in explants cultured with cells directly exposed to the culture media the cells appeared to be shorter, globular and haphazardly arranged. FGF initiated the differentiation of most lens epithelial cells; however, abnormal cellular morphologies developed with subsequent culture of the cells. As a result, the transparency of these explants decreased with prolonged culture. Interestingly, explants cultured with vitreous (i) did not develop abnormal cellular morphologies, (ii) contained two distinct cell types (retained epithelial cells and newly differentiated fibre cells) and (iii) remained transparent throughout the lengthy culture period. In summary, we have developed a culture system that generates a transparent tissue with a cellular arrangement resembling that of the lens in vivo. We have shown that while FGF and vitreous initiate differentiation within this system, better maintenance of fibre cell integrity, more appropriate regulation of molecular events, and better maintenance of explant transparency was achieved in the presence of vitreous. This system offers an opportunity to further investigate the process of lens fibre cell differentiation as well as a means of better identifying the factors that contribute to the development of tissue transparency in vitro.

Identification of unknown intraocular material after cataract surgery: evaluation of a potential cause of toxic anterior segment syndrome.

PURPOSE: To describe and identify unknown opaque material between the optic of an AR40 intraocular lens (IOL) injected with the Emerald Series implantation system (both AMO, Inc.) and the posterior capsule at the conclusion of routine phacoemulsification to prevent an outbreak of toxic anterior segment syndrome (TASS). SETTING: Ambulatory care center operating room, University of North Carolina Hospitals and Department of Ophthalmology, University of North Carolina School of Medicine at Chapel Hill, Chapel Hill, North Carolina, USA. METHODS: After coaxial phacoemulsification in multiple patients, opaque material was present between the optic of a posterior chamber IOL and the posterior capsule. Although there was no TASS, the material was removed from 2 eyes and analyzed with scanning electron microscopy (SEM) and x-ray microanalysis (XRM). Similarly, crystalline lens, Klenzyme (Steris Corp.), Viscoat (sodium hyaluronate 3.0%-chondroitin sulfate 4.0%), and Provisc (sodium hyaluronate 1.0%) were analyzed. RESULTS: On SEM, the material had an irregular undulating surface similar to that of Provisc. Viscoat and the crystalline lens had smoother surfaces. On XRM, the material contained sodium, chlorine, and calcium, like Viscoat and Provisc, and phosphorous and sulfur, like Viscoat. The material also contained silicone, magnesium, aluminum, titanium, iron, and zinc. Klenzyme had smaller peaks of sodium, chlorine, and calcium and a higher carbon background than the unknown material. CONCLUSIONS: The material was likely ophthalmic viscosurgical device that was chemically and structurally altered by the cleaning and sterilization process. The silicone and metallic elements were probably from the Emerald Series implantation system as the disposable cartridge is coated with silicone and the reusable injector is metal.