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PubMed1983

Selective trabeculectomy. A report of a new surgical method for open angle glaucoma.

A new instrument, the trabeculectome, and an new surgical method for treating open angle glaucoma is described. The double-edged instrument makes 2 cuts through the trabecular meshwork while being pulled through Schlemm's canal, thus cutting free a strip of the trabecular meshwork and the inner wall of Schlemm's canal. The results of the 21 first operations are presented. The observation time is 9-19 months. The characteristic post-operative pressure pattern is an immediate fall to 10-20 mmHg followed by a period of higher pressures which then converge to the range of 8-16 mmHg with most eyes in the 10-14 mmHg range. Four patients need timolol treatment to obtain this, the remaining 17 have no medication. The therapeutic results and additional observations are discussed with special interest to possible physiological mechanisms.

Acetazolamide↗
PubMed2004

Gene expression profile of the rat eye iridocorneal angle: NEIBank expressed sequence tag analysis.

PURPOSE: To characterize gene expression pattern in the combined tissues of the rat iridocorneal angle by expressed sequence tag (EST) analysis, as part of the NEIBank project. METHODS: RNA was extracted from dissected tissues of the rat iridocorneal angle (iris, ciliary body, trabecular meshwork, and Schlemm's canal) and used to construct unamplified, non-normalized cDNA libraries in the pSPORT1 vector. Approximately 5000 clones were sequenced from the 5'-end. Clones were clustered and identified using the GRIST software, a procedure based on BLAST comparisons. Complete sequences of several novel cDNAs showing eye-preferred expression patterns were obtained. The expression patterns of several genes have been investigated by Northern blot and in situ hybridization, as well as by RT-PCR. RESULTS: After analysis and removal of non-mRNA sequences, 2195 independent clusters, potentially representing individual eye angle-expressed clones were obtained. The expression profile of the combined rat eye angle tissues was more similar to that of the human iris than to human trabecular meshwork. Several cDNAs encoding transcription factors essential for normal eye development and function including Pax-6, Six3, c-Maf, Maf1, Sox-4, Foxc1, Rx, and Ldb2 were present among sequenced clones. A number of tested cDNAs showed eye-preferred expression patterns. Myocilin, which is abundant in human eye angle tissues, was not observed in the rat collection; however, transcripts for three other olfactomedin-domain proteins were seen. Latrotoxin receptor (CL1AA) and optimedin were shown to be expressed in the iris and ciliary body, as well as in the ganglion and inner nuclear cell layers of the retina, whereas the rat orthologue of the human HNOEL-iso gene was expressed in the iris and sclera and less actively in the trabecular meshwork, retina, and optic nerve. CONCLUSIONS: The iridocorneal libraries are a good source of novel uncharacterized genes and molecular markers for the tissues of the eye angle. Although myocilin is not abundantly expressed in rat eye angle, other olfactomedin-containing genes are expressed there and may play important roles in normal eye function and disease.

Amino Acid Sequence↗
PubMed1996

[Risk factors for development of argon laser trabeculoplasty failure producing membrane in the chamber angle].

INTRODUCTION: The major cause of ALT failure is membrane formation in the chamber angle. The aim of this retrospective study was to identify possible risk factors. MATERIAL AND METHODS: We studied sections from the surgical specimens from all trabeculectomies at our department within 2 years. We identified 122 eyes with at least one preoperative ALT. In 46 specimens enough trabecular meshwork for morphological analysis was present. RESULTS: Half of the patients showed a membrane covering the trabecular meshwork. In 14 of 23 eyes we could see this membrane even at low-power magnification (40 x). Various possible risk factors were evaluated, but none showed a significant correlation. When we compared only these eyes with membranes visible at low-power magnification with eyes without, however, we found a significant difference in the number of ALTs (mean +/- SD 2.07 +/- 0.73 vs 1.48 +/- 0.59; P = 0.026) and preoperative intraocular pressure (32.0 +/- 9.7 mmHg vs 26.2 +/- 8.4 mmHg; P = 0.04). CONCLUSION: We found no distinct risk factor for membrane formation, but it becomes more frequent with every additional laser treatment.

Adult↗
PubMed2000

Distribution of glucocorticoid and mineralocorticoid receptors and 11beta-hydroxysteroid dehydrogenases in human and rat ocular tissues.

PURPOSE: The administration of glucocorticoids as topical or systemic medications may lead to the development of ocular hypertension through the induction of morphologic and biochemical changes in the trabecular meshwork leading to a reduction in the facility of aqueous outflow. Glucocorticoids exert their physiological effects by binding to and activating glucocorticoid and mineralocorticoid receptors. The activity of glucocorticoids is critically regulated at a prereceptor level by the two isozymes of 11beta-hydroxysteroid dehydrogenase. The purpose of this study was to determine the distribution of glucocorticoid target receptors and the isozymes of 11beta-hydroxysteroid dehydrogenase (11 beta-HSD) that regulate the activity of glucocorticoids at a prereceptor level in human and rat ocular tissues. METHODS: Horizontal sections of normal adult human and rat eyes were cut and hybridized with 35S-labeled cRNA probes specific for the glucocorticoid receptor, mineralocorticoid receptor, and 11beta-HSD types 1 and 2 using in situ hybridization. Immunohistochemical analysis of glucocorticoid and mineralocorticoid receptors using monoclonal antibodies was carried out on rat eye tissue sections. Whole rat eyes were homogenized and the activity of 11beta-HSD types 1 and 2 in the eye assessed as the percentage conversion of tritiated corticosterone to tritiated 11-dehydrocortico-sterone when corticosterone was added to the homogenate. RESULTS: In the rat ocular tissues mRNAs encoding glucocorticoid receptor, mineralocorticoid receptor, and 11beta-HSD types 1 and 2 were detected in nonpigmented ciliary epithelium, trabecular meshwork, corneal epithelium and endothelium, and anterior lens epithelium. Immunohistochemistry confirmed the presence of glucocorticoid and mineralocorticoid receptors at these sites. Activity of both isozymes of 11beta-HSD was demonstrated in homogenized rat eyes (percentage conversion of tritiated corticosterone to 11-dehydrocorticosterone; mean +/- SD, 11beta-HSD 1 = 15% +/- 5.3%, 11beta-HSD 2 = 7.9% +/- 2.8%). In both human and rat eyes, expression of mRNAs encoding glucocorticoid receptor and 11beta-HSD type 1 was high in the trabecular meshwork and lens epithelium, whereas expression of mRNAs encoding the mineralocorticoid receptor and 11beta-HSD type 2 was high in nonpigmented ciliary epithelium and corneal epithelium and endothelium. CONCLUSIONS: Glucocorticoid target receptors and the enzymes regulating glucocorticoid activity at these receptors are present in mammalian ocular tissues, which regulate aqueous humor formation and outflow. Alteration in the number or affinity of receptors or in the activity of regulatory enzymes may alter the susceptibility of certain individuals to the effects of glucocorticoids on intraocular pressure.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1985

Short-term effect of argon laser trabeculoplasty in monkeys.

We performed argon laser trabeculoplasty (ALT) in four cynomolgus monkeys and evaluated the morphologic changes in the trabecular meshwork one hour and 14 hours following the laser treatment. One hour after ALT, disruption of the trabecular beams and coagulative necrosis of the tissue were evident. Fragmented cells and fibrillar tissue debris were found in the trabecular spaces, accumulating in the juxtacanalicular region. This might explain the elevation of intraocular pressure seen immediately following ALT in some glaucomatous patients. Also, many trabecular endothelial cells were rounded up, displaying different stages of leaving the beams; these cells were actively phagocytic. Such stimulation of trabecular meshwork cells with subsequent removal of tissue debris might explain the temporary nature of elevation of intraocular pressure following ALT.

Animals↗
PubMed1984

[The technic of argon laser trabeculoplasty and its results].

Argon laser trabeculoplasty (ALT) was performed on 130 eyes with primary open-angle glaucoma or capsular glaucoma. Three different methods of ALT were employed to determine if the methods itself affects the incidence of immediate postoperative rises in intraocular pressure (IOP). Thirty-five eyes received 100 burns over 360 degrees of the posterior trabecular meshwork; these were categorized as Group 1. Group 2 comprised 77 eyes given 50 burns over 180 degrees of the posterior meshwork. Group 3 consisted of 18 eyes treated with 50 burns over 180 degrees of the anterior trabecular meshwork. The duration of each burn was 0.2 s in Group 1 and 0.1 s in Groups 2 and 3. The power of each burn ranged from 700 to 1000 mW in each group. Immediate postlaser IOP rise was defined as a pressure elevation exceeding prelaser value by 5 mmHg or more. In Group 1 the incidence of IOP rise was 82%; it was 58% after the first session in Group 2, but only 22% in Group 3. A sustained, marked pressure rise was most frequently observed in Group 1 as compared with the other two groups. Other complications, including sustained iritis, peripheral anterior synechiae and hyphema, were seen most frequently in Group 1 and least frequently in Group 3. Successful control of IOP, defined as an IOP of less than 20 mmHg, was achieved in 37% in Group 1, 70% in Group 2 and 56% in Group 3. The follow-up period ranged from 1.5 to 52 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Glaucoma, Open-Angle↗
PubMed1982

[Immunopathogenesis of primary open-angle glaucoma].

By means of direct immunofluorescence technique the trabecular meshwork of patients with primary open-angle glaucoma, obtained at the time of filtering surgery, and the trabecular meshwork of controls were investigated for the presence of immunoglobulins and the complement component C3. In neither group were such deposits found; this indicates a lack of immunogenic mechanisms in primary open-angle glaucoma.

Fluorescent Antibody Technique↗
PubMed2004

A review of genetic and structural understanding of the role of myocilin in primary open angle glaucoma.

Primary open angle glaucoma (POAG) is the most common form of glaucoma and the second leading cause of blindness in the world. Discovery of the candidate gene MYOC (TIGR/MYOC) encoding the protein myocilin, believed to have a role in cytoskeletal function, might play a key role in understanding the pathogenesis of POAG. MYOC is expressed in many ocular tissues, including trabecular meshwork (TM), a specialised eye tissue essential in regulating intraocular pressure (IOP). Later it was shown to be the trabecular meshwork inducible-glucocorticoid response protein (TIGR). Mutations in MYOC have been identified as the cause of hereditary juvenile-onset open-angle glaucoma (JOAG). The unprocessed myocilin with signal peptide is a 55-kDa protein with 504 amino acids. Mature myocilin is known to form multimers. Wild type myocilin protein is normally secreted into the trabecular extracellular matrix (ECM) and there appears to interact with various ECM materials. It is believed that the deposition of high amounts of myocilin in trabecular ECM could affect aqueous outflow either by physical barrier and/or through cell-mediated process leading to elevation of IOP. The N-terminal region of the myocilin has sequence similarity to myosin (muscle protein) and the C-terminal of the protein has an olfactomedin-like domain. Structural and genetic studies of the MYOC gene and its protein product along with molecular modeling could lead to better understanding of the pathogenesis of POAG. This review highlights the current understanding of myocilin and the relevance of genetic and structural work.

Cytoskeletal Proteins↗
PubMed1997

A rat model of chronic pressure-induced optic nerve damage.

To develop unilateral, chronically elevated intraocular pressure in rats, episcleral veins were injected with hypertonic saline and the intraocular pressure was monitored with a Tono-Pen XL tonometer. Histologic analyses of eyes with differing degrees and durations of intraocular pressure elevation were performed to ascertain the effects of these pressures on the optic nerve. Out of 20 consecutive animals, nine had elevations of intraocular pressure following a single injection, while subsequent injections raised intraocular pressure in seven others. One eye became hypotonous. In the remaining animals, subsequent injections sufficient to raise intraocular pressure were deliberately withheld, to determine the possible direct effects of injections on the optic nerve. Mean sustained pressure elevations ranged from 7 to 28 mm Hg and the retinal vasculature remained perfused in all eyes. Optic nerve cross sections from eyes without intraocular pressure elevation appeared identical to those from uninjected eyes, while nerves from eyes with the greatest intraocular pressure rise demonstrated axonal damage that involved 100% of the neural area. Eyes with either less severe pressure elevations or shorter durations showed partial damage, ranging from 0.5% to 10.4% of the neurla area. In 70% of these nerves, damage was concentrated in the superior temporal region. Within the optic nerve head, often associated with astrocytes, axons contained abnormal accumulations of membrane-bound vesicles and mitochondria. The anterior chamber angles showed sclerosis of the trabecular meshwork with anterior synechiae, but Schlemm's canal, collector channels and aqueous veins appeared patent. Unilateral sclerosis of the trabecular meshwork produces sustained elevation of intraocular pressure in rats with optic nerve damage that in many ways resembles that seen in human glaucoma. Understanding the mechanism of nerve damage in this model may provide new insights into the pathogenesis of human glaucoma.

Animals↗
PubMed1996

Ocular adenovirus gene transfer varies in efficiency and inflammatory response.

PURPOSE: To study the effects of adenoviral gene transfer to the tissues of the anterior segment in vitro by rat and monkey lens organ cultures and in vivo by single injection into the anterior chamber of rabbits. METHODS: In vitro, intact lens cultures were exposed to 1 to 4 x 10(8) pfu Av1LacZ4 and Av1Luc1 in TC199 medium containing no serum or growth factors. Av1LacZ4 and Av1Luc1 are replication-deficient adenovirus vectors, carrying the reporter genes Escherichia coli LacZ and firefly luciferase, respectively. In vivo, the anterior chambers of eight rabbits were injected once with 20 mumol Av1LacZ4 (8 x 10(8) pfu) and evaluated 48 hours after injection. Enzyme activity of the reporter genes was measured biochemically and histochemically. RESULTS: In organ cultures, adenovirus delivers reporter genes efficiently to the ciliary processes but penetrates poorly into the capsulated lenses. Viral receptors, however, are present in rat lens epithelium, as in primary trabecular meshwork and other lens cell lines. In vivo, gene transfer was evident in corneal endothelium, iris anterior surface, and trabecular meshwork. Presence of the virus did not affect lens transparency or provoke external discomfort signs. Infected corneal endothelial cells were swollen and partly detached; 3 of 8 infected eyes showed a severe inflammatory response in chamber angle, anterior uvea, and limbal conjunctiva. CONCLUSIONS: These findings reveal the distinct gene transfer potential of each of the tissues of the anterior segment and emphasize the need to address the inflammatory response to these first-generation adenoviral vectors.

Adenoviruses, Human↗
PubMed2025

Exploring diagnostic m6A regulators in primary open-angle glaucoma: insight from gene signature and possible mechanisms by which key genes function.

PURPOSE: The purpose of this study was to interrogate the potential role of N6-methyladenosine (m6A) regulators in the process of trabecular meshwork (TM) tissue damage in patients with primary open-angle glaucoma (POAG). METHODS: Firstly, the expression profile of m6A regulators in TM tissues of POAG patients was comprehensively analyzed by bioinformatics analysis; Plasmid transfection and siRNA gene interference were used to enhance or weaken the expression levels of YTHDC2 in human trabecular meshwork cells (HTMCs); Cell migration ability was detected by transwell chamber assay; Immunofluorescence staining assay was used to evaluate the expression of extracellular matrix (ECM) related proteins. RESULTS: Through the analysis of GSE27276 database, 5 m6A regulators with different expression in POAG were screened out. The results of random forest model showed that these 5 m6A regulators exhibited diagnostic potential and were characteristic genes of POAG. All POAG samples could be effectively divided into two groups based on the expression levels of these 5 hub m6A regulators. Immune cell infiltration analysis indicated that the levels of activated CD8+ T cells and regulatory T cells were different in the two subtypes. HTMC oxidative stress cell model and TGF-β2 stimulation cell model were further constructed to verify the expression of the aforementioned hub m6A regulators, and it was found that YTHDC2 mRNA showed the same expression trend in both models. The silencing of YTHDC2 enhanced the migration ability of HTMCs and increased the synthesis ability of ECM. However, when YTHDC2ΔYTH, which lacks the YTH domain, is overexpressed in HTMCs, there is no significant change in the ECM synthesis ability. CONCLUSIONS: The differentially expressed m6A regulators in TM tissues may serve as potential diagnostic biomarkers for POAG. And, in HTMCs, the expression level of YTHDC2 mRNA was changed under oxidative stress or TGF-β2 intervention, and then exerted its regulation on cell migration and ECM synthesis capability through m6A modification, which may be an important part of the disease process of POAG.

Humans↗
PubMed2004

Late hypotony as a complication of viscocanalostomy: a case report.

BACKGROUND: We report a long-term hypotony syndrome after deep sclerectomy, associated with intermittent rise in intraocular pressure (IOP) due to steroid response. PATIENT PRESENTATION: A 55-year-old woman with high myopia (RE -9.25, LE -10.50) suffering from uncontrolled pigment open-angle glaucoma, despite laser trabeculoplasty and a cyclodestructive procedure, underwent an uneventful viscocanalostomy. FOLLOW-UP: Intraocular pressure was between 9 and 17 mm Hg with local steroid medication 5 times a day, but became unstable with steroid reduction to 3 times a day and the patient developed hypotonous IOP (3-5 mm Hg) in the fourth postoperative month. With intensification of local steroid therapy, IOP rose to 49 mm Hg, and a reduction in medication was followed by hypotony. The instability of IOP with steroid medication could not be controlled and the IOP response due to steroids diminished with time; a long-term hypotony syndrome with maculopathy developed. Surgical inspection 10 months later with repeated preparation of the scleral flap showed (like ultrasound biomicroscope examination) a normal status after viscocanalostomy, without signs of leakage. CONCLUSIONS: Late hypotony syndrome should be considered as a potential complication of viscocanalostomy, perhaps especially in cases of myopia and former cyclodestructive procedures. In our case, despite nonpenetrating glaucoma surgery, the steroid response at first observed indicated additional outflow via the trabecular meshwork. After some months it could not be provoked any longer, leaving us to consider whether a gradual change in the trabecular meshwork hinders steroid medication changing aqueous outflow facility.

Antihypertensive Agents↗
PubMed1984

Ultrastructural and pharmacologic studies on laser-induced glaucoma in primates and rabbits.

Sustained high intraocular pressure resulting in optic nerve cupping and loss of ganglion cells was produced in five rhesus monkeys and eight pigmented rabbits by applying argon laser energy to the trabecular meshwork. In addition, the rabbits manifested buphthalmus. Flow of carbon particles subsequently injected into the anterior chamber was obstructed at the trabecular meshwork by a wound-healing response that closed the intratrabecular spaces. Besides this sustained high intraocular pressure as a result of late scarring, an acute hypertensive response was seen in all rabbits which may correspond to the acute hypertension seen after laser trabeculoplasty in humans. The acute hypertensive response could be only partially blocked by prostaglandin inhibitors and we believe that prostaglandins are not primarily responsible for this effect. Medications known to lower intraocular pressure were systematically tested in both glaucoma models.

Animals↗
PubMed2006

Gonioscopy in adult Chinese: the Liwan Eye Study.

PURPOSE: To assess gonioscopic characteristics of the drainage angle in adult Chinese in an urban area of southern China. METHODS: Clustered random sampling was used to select adults aged 50 years and older in Liwan District, Guangzhou. Gonioscopy was performed on all the subjects. The geometric angle width was graded in the superior and inferior quadrants, according to the Spaeth system. In addition, apparent and true iris insertion was classified in four quadrants with static and dynamic gonioscopy. The peripheral iris profile was described as steep, regular, concave, and plateau. Data are presented for all phakic right eyes. Secondary or iatrogenic cases were excluded in the analysis of peripheral anterior synechiae (PAS). RESULTS: Among 1405 participants in the study, data from 1330 (95%) right eyes were available for analysis. Iridotrabecular angles (ITA) < or =20 degrees were present in 36.9% (95% CI: 34.3%-40.0%) of eyes superiorly and in 27.9% (95% CI: 25.5%-30.4%) inferiorly. Narrower ITAs were more common in the older people (sex-adjusted odds ratio [OR] = 1.1 per year of life; P < 0.001) and the women (age-adjusted OR = 2.5, P < 0.001). Apparent iris insertion of grade A or B (with pigmented trabecular meshwork not visible) by quadrant was observed in 27.2% superiorly, 12.0% nasally, 7.7% inferiorly, and 14.2% temporally. Narrow angles (in which pigmented trabecular meshwork was not visible in three or more quadrants) were identified in 11.0% (95% CI: 9.3%-12.7%) of right eyes. Overall, 33.3% of eyes had a steep iris profile, 54.2% were normal, 2.7% were concave, and 10.1% were graded plateau. PAS were seen in 30 of 146 (20.5%) eyes with narrow angles and in 7 (0.6%) of 1184 eyes with angles that did not meet criteria for narrow angles. PAS were more likely with narrower angles, with 0%, 0.3%, and 1.9% of eyes with a mean ITA of 40 degrees, 30 degrees, and 20 degrees, respectively, having PAS as opposed to 12.6% and 27.5% for those with ITA 10 degrees and 0 degrees , respectively. CONCLUSIONS: Ten percent of this population of southern Chinese persons 50 years of age and older had narrow angles. PAS were present in one fifth of these people. From these cross-sectional data, it is unclear which of these individuals are at highest risk of the development of primary angle-closure (PAC) glaucoma. Longitudinal studies are necessary to determine appropriate strategies for preventing this potentially blinding outcome.

Aged↗
PubMed1997

Immunoelectron microscopic localization of the HNK-1 carbohydrate epitope in the anterior segment of pseudoexfoliation and normal eyes.

PURPOSE: To study the presence of the cell-adhesion related HNK-1 carbohydrate epitope in the anterior segment of pseudoexfoliation and normal eyes by immunoelectron microscopy. METHODS: Anterior segment tissue of 6 autopsy eyes with pseudoexfoliation (PEX) syndrome (5 eyes without glaucoma and 1 with glaucoma), and 6 normal autopsy eyes without PEX syndrome were studied by an electron microscopic immunogold technique using a monoclonal antibody to the HNK-1 epitope. RESULTS: In both normal and PEX eyes, the HNK-1 epitope could be immunolocalized to the basement membranes of both ciliary epithelia and posterior iris pigmented epithelium, to the lens capsule and zonular lamella, and to the pigmented epithelial cells of iris and ciliary body. Within the inner connective tissue layer of the ciliary body, the gold label was mainly associated with the periphery of elastic fibers and microfibrillar bundles. PEX material on the surfaces of posterior iris, ciliary body, anterior lens capsule, zonular fibers, and uveal part of the trabecular meshwork reacted strongly with the HNK-1 antibody. In contrast, PEX material accumulations within the iris stroma or the juxtacanalicular tissue of the trabecular meshwork showed only weak immunoreactivity, while PEX material in the conjunctiva was totally negative. CONCLUSIONS: The wide distribution of the HNK-1 epitope in anterior segment tissues and its association with a variety of extracellular and cellular structures was ultrastructurally demonstrated. In PEX syndrome, the varying labelling density of PEX fibers indicates a deviating carbohydrate composition in different locations of the eye. The HNK-1 epitope might be involved in the adhesiveness of PEX deposits on intraocular surfaces.

Aged↗
PubMed2006

Immunopathology of intraocular silicone oil: enucleated eyes.

AIMS: To characterise the distribution of silicone oil in ocular tissues in globes enucleated after complicated retinal detachment, and to document the distribution and nature of any associated inflammatory response. METHOD: 9 enucleated globes that had previously undergone retinal detachment surgery with silicone oil and 7 control globes that had undergone enucleation after retinal detachment surgery (n = 2) or ocular trauma (n = 5) were studied. Sections were histologically examined using light microscopy to document the distribution of silicone oil in ocular tissues. Immunohistochemical analysis was carried out using the ABC technique and a panel of monoclonal and polyclonal antibodies. Electron microscopy was undertaken to observe the penetration of silicone oil in the trabecular meshwork of the anterior chamber drainage angle. RESULTS: Silicone oil was distributed throughout the globes-notably in the iris, ciliary body, retina, trabecular meshwork and epiretinal membranes. Focal areas of intraretinal silicone were associated with disorganised retinal architecture, retinectomy sites or subretinal oil. The distribution of macrophages was closely related to the distribution of silicone oil. T and B lymphocytes were not associated with silicone oil unless additional pathology was also present-for example, cyclitic membrane or uveitis. One of the nine eyes had silicone oil present in the optic nerve. In the control globes, the inflammatory response was mediated primarily by macrophages and T lymphocytes, and was less marked than that observed in the silicone oil globes. CONCLUSION: This study shows that silicone oil may be sequestered in varied ocular tissues and is associated with localised inflammation mediated by macrophages.

Adolescent↗
PubMed1996

Distribution and characterization of proteoglycans associated with exfoliation material.

PURPOSE: To examine the distribution of proteoglycans in the exfoliation materials in order to investigate the nature of the materials. METHODS: The anterior parts of two eyes with exfoliation syndrome were examined by electron microscopy after staining with cupromeronic blue (cmb). Some specimens were treated with enzymes and/or nitrous acid prior to staining. The effects of the enzymes were evaluated statistically by counting the density of the cmb-positive filaments in the exfoliation materials, using a computer. One eye with exfoliation syndrome stained with alcian blue was observed with light microscopy. RESULTS: Exfoliation materials were observed along the epithelial cells of the iris and ciliary body, and in the trabecular meshwork and zonules. In tissue specimens treated with cmb, electron-dense filaments were seen associated with the exfoliation materials. Microfibrils in the trabecular meshwork and iris, and zonular fibrils themselves were free of any filament staining, while the exfoliation materials located closely to the fibrils contained the electron-dense filaments. In the tissue specimens treated with chondroitinase AC, chondroitinase B, chondroitinase ABC or nitrous acid before cmb staining, the amount of the filament associated with exfoliation materials decreased in comparison to the controls. Digestion with keratinase did not demonstrate any significant changes in staining. A combination treatment with chondroitinase ABC and nitrous acid eliminated almost all filaments associated with the exfoliation materials. In the eye stained with alcian blue, the zonules that did not stain for the dye demonstrated an accumulation of exfoliation materials that stained strongly for alcian blue. CONCLUSIONS: Exfoliation materials contain chondroitin sulfate, dermatan sulfate, heparan sulfate proteoglycans. Depositions of proteoglycans on the microfibrils may be closely associated with the formation of exfoliation materials.

Aged↗
PubMed1985

Morphologic studies of uveoscleral outflow in normotensive and glaucomatous beagles with fluorescein-labeled dextran.

Aqueous humor leaves the anterior chamber through 2 pathways: the trabecular meshwork of the iridocorneal angle and the unconventional uveoscleral route. In the latter route, aqueous humor leaves the anterior chamber, passes caudally through the trabecular meshwork and sclerociliary cleft to enter the supraciliary and suprachoroidal spaces. The fluid is absorbed by the choroidal and scleral circulation. Fluorescein-labeled dextran was slowly infused into the posterior chamber of healthy and glaucomatous Beagles for 30 minutes. The eyes were fixed in a mixture of 70% alcohol and formalin, placed in epoxy resin for histologic evaluation, and examined by fluorescent microscopy. Fluorescence was detected in the healthy dogs throughout the uveoscleral pathway. In the glaucomatous dogs, the uveoscleral outflow was decreased or completely absent.

Animals↗