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.

Type VII Collagen in the Human Accommodation System: Expression in Ciliary Body, Zonules, and Lens Capsule.

Purpose: To investigate intraocular expression of COL7A1 and its protein product type VII collagen, particularly at the accommodation system. Methods: Eyes from 26 human adult donors were used. COL7A1 expression was analyzed in ex vivo ciliary epithelium by microarray. Type VII collagen distribution was examined by Western blot analysis, immunohistochemistry. and immuno-electron microscopy. Results: COL7A1 is expressed by pigmented and nonpigmented ciliary epithelia. Type VII collagen is distributed particularly at the strained parts of the accommodation system. Type VII collagen was associated with various basement membranes and with ciliary zonules. Anchoring fibrils were not visualized. Conclusions: Type VII collagen distribution at strained areas suggests a supporting role in tissue integrity.

Micromorphology analysis of the anterior human lens capsule.

PURPOSE: This study aimed to quantify the three-dimensional micromorphology of the surface of the human lens capsule as a function of age. METHODS: Imaging experiments were conducted on whole human lenses received from eight human cadavers (donor age range: 30-88 years). Imaging was performed with an atomic force microscope (AFM) in contact mode in fluid. The porosity and surface roughness were quantified from the height images obtained. A novel approach, based on stereometric and fractal analysis of three-dimensional surfaces developed for use in conjunction with AFM data, was also used to analyze the surface microtexture as a function of age. RESULTS: The AFM images obtained depict a highly ordered fibrous structure at the surface of the lens capsule, although the overall structure visually changes with age. Porosity and roughness were quantified for each image and analyzed as a function of donor age. The interfibrillar spacing revealed an increasing trend with age, although this result was not significant (p = 0.110). The root mean square (RMS) deviation and average deviation significantly decreased with increasing age (p<0.001 for both). The fractal analysis provided quantitative values for 29 amplitude, hybrid, functional, and spatial parameters. All the hybrid parameters decreased with age, although not significantly. Of the functional parameters, the surface bearing index increased significantly with age (p = 0.017) and the summit height exhibited a decreasing trend with age (p = 0.298). Of the spatial parameters, the dominant radial wavelength trend moved toward an increase with age (p = 0.103) and the cross-hatch angle tended toward a decrease with age (p = 0.213). CONCLUSIONS: Significant changes in the three-dimensional surface microtexture of the human lens capsule were found with age, although more experiments on a larger dataset are needed to conclude this with certainty. The analyzed AFM images demonstrate a fractal nature of the surface, which is not considered in classical surface statistical parameters. The surface fractal dimension may be useful in ophthalmology for quantifying human lens architectural changes associated with different disease states to further our understanding of disease evolution.

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.

Lens capsule structure assessed with atomic force microscopy.

PURPOSE: To image the ultrastructure of the anterior lens capsule at the nanoscale level using atomic force microscopy (AFM). METHODS: Experiments were performed on anterior lens capsules maintained in their in situ location surrounding the lens from six human cadavers (donor age range: 44-88 years), four cynomolgus monkeys (Macaca fascicularis age range: 4.83-8.92 years), and seven pigs (<6 months). Hydration of all samples was maintained using Dulbecco's Modified Eagle Medium (DMEM). Whole lenses were removed from the eye and placed anterior side up in agarose gel before gel hardening where only the posterior half of the lens was contained within the gel. After the gel hardened, the Petri dish was filled with DMEM until the point where the intact lens was fully submerged. AFM was used to image the anterior lens surface in contact mode. An integrated analysis program was used to calculate the interfibrillar spacing, fiber diameter, and surface roughness of the samples. RESULTS: The AFM images depict a highly ordered fibrous structure at the surface of the lens capsule in all three species. The interfibrillar spacing for the porcine, cynomolgus monkey, and human lens capsules was 0.68±0.25, 1.80±0.39, and 1.08±0.25 µm, respectively. In the primate, interfibrillar spacing significantly decreased linearly as a function of age. The fiber diameters ranged from 50 to 950 nm. Comparison of the root mean square (RMS) and average deviation demonstrate that the surface of the porcine lens capsule is the smoothest, and that the human and cynomolgus monkey capsules are significantly rougher. CONCLUSIONS: AFM was successful in providing high-resolution images of the nanostructure of the lens capsule samples. Species-dependent differences were observed in the overall structure and surface roughness.

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.

AFM study for morphological characteristics and biomechanical properties of human cataract anterior lens capsules.

The aim of this study was to quantitatively investigate the morphologies (surface roughness) and biomechanical properties (Young's modulus) of human anterior lens capsules (ALCs) for noncataract and cataract groups using atomic force microscopy. Eight human ALCs obtained during phacoemulsification from patients with senile cataracts (72 ± 13 years) were investigated in both the hydrated and dehydrated conditions. The cataract group showed clearly the proliferated lens epithelial cells (LECs) with a monomorphic cell structure, a diameter of 12.54 ± 4.31 µm, and a height of 0.23 ± 0.04 µm, whereas the control group showed no LECs. A substantial amount of false-positive calcification was observed caused by the deposition of remnants of dried salt solution. Cataract group showed significantly higher surface roughness (382.06 nm, p ≤ 0.001) than control group in the anterior side of ALCs, whereas cataract group showed significantly lower surface roughness (353.79 nm, p ≤ 0.001) than control group in their posterior side. Cataract group showed significantly higher Young's modulus (69.52 kPa, p ≤ 0.001) compared to the control group, regardless of the ALC side. Therefore, it is significant that this study provides a new method to examine the nanostructural characteristic and biomechanical property of human ALCs through a nanometer-scale resolution microscopy technique.

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.

Abnormal fiber end migration in Royal College of Surgeons rats during posterior subcapsular cataract formation.

PURPOSE: Prior structural studies of posterior subcapsular cataract (PSC) development in Royal College of Surgeons (RCS) rats suggest that migration of basal fiber ends was disrupted, ultimately resulting in a PSC. Therefore the goal of this study was to assess the overall migration patterns as well as changes to the structure and cytoskeleton of basal fiber ends during PSC development. METHODS: Lenses from 48 RCS dystrophic rats (RCS/Lav) and 24 genetically matched control animals (RCS-rdy(+)/Lav) from 2 to 8 weeks old were examined. Equatorial diameters were measured and suture patterns were photographed immediately following enucleation/dissection. Right eye lenses were fixed and processed to visualize the actin cytoskeleton via laser scanning confocal microscopy (LSCM), left eye lenses were decapsulated, fixed and processed for scanning electron microscopy (SEM). Scaled 3D-computer assisted drawings (CADs) and animations were constructed from the data to depict the changes in suture patterns and fiber end architecture. RESULTS: At 2 weeks, dystrophic lenses displayed an inverted Y suture on the posterior, and by 3 weeks most lenses had at least one sub-branch. Additional sub-branches were observed with time, opacities being visible as early as 4 weeks and progressing into PSC plaques by 6 weeks. Control lenses displayed inverted Y sutures at all ages and were transparent. SEM of dystrophic lenses revealed fiber ends with normal size, shape, arrangement, and filopodia at 2 weeks; scattered areas of dome-shaped fiber ends and small filopodia were present at 3 weeks. At 4 weeks the irregularly arranged domed fiber ends had extremely long filopodia with 'boutons' at their tips. By 6 weeks all fiber ends within plaques displayed rounded or domed basal membranes and lacked filopodial extensions. Control lenses at all time points had comparable ultrastructure to the 2 week old dystrophic lenses. F-actin arrangement within the basal membrane complex (BMC) of control lenses showed the expected peripheral pattern of labeling at all ages. Dystrophic RCS lenses at 2 weeks were comparable to controls, however by 3-4 weeks they displayed scattered foci of F-actin within the BMC. At all time points thereafter, F-actin was rearranged into a 'rosette' pattern of prominent foci at cell vertices. CONCLUSIONS: The data are consistent with the hypothesis that migration of basal fiber ends is altered in a two stage process wherein initially, migration patterns undergo a rapid shift resulting in abnormal suture sub-branch formation. Subsequent cytological alterations are consistent with an eventual cessation of migration, precluding proper targeting of basal ends to their sutural destinations and leading to cataract plaque formation.

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.