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PubMed1983

[Results of argon laser treatment of 100 eyes with open-angle glaucoma (trabeculoplasty, trabeculoretraction)].

One hundred phakic eyes of 76 patients with primary open angle glaucoma received argon laser therapy to the trabecular meshwork, a method, based on the works of James Wise, which we prefer to call trabecular retraction for two reasons: 1) the mechanical factor of trabecular tightening caused by the laser microscars and 2) to differentiate it from initial argon laser treatment in primary open angle glaucoma: trabeculopuncture. Argon laser trabecular retraction involves application to the entire pigmentary trabecular ring, just anterior to the scleral spur, of 100 evenly spaced non-penetrating burns, using a 50 microM. beam diameter with a pulse duration of 0,1 sec, and a power level adjusted to produce a minimum visible trabecular reaction. Laser treatment was performed on an out-patient basis using a three mirror Goldmann lens after topical anesthesia. Pre-laser anti-glaucoma medical treatment was continued unchanged during the follow-up period of this study, to assess accurately the effect of the laser treatment on intraocular pressure (IOP) without introducing the variable of changing medications. Treatment was applied to eyes with uncontrolled glaucoma on maximum tolerable medical therapy and, as such, candidates for surgery, eyes of patients unable to tolerate side effects of effective intensive medical therapy, and eyes with controlled open angle glaucoma to permit reduction of medical therapy. Mean pressure drop in the 100 eyes was 8,9 mmHg, the reduction of IOP being achieved between 3 and 6 weeks after the laser procedure. Surgery for glaucoma was avoided in 93% of the eyes. Pressure drop in 75% of treated eyes was between 4 and 11 mmHg, in 16% was 12 mmHg or more, and in 9% was 3 mmHg or less. Follow-up was for at least three months and in some cases extended to 15 months. These results and data from published reports suggest that the pressure drop obtained three months post-laser could be considered definitive, except in a very small percentage of eyes. Average intraocular pressure reduction in patients under 60 years was 8,3 mmHg and 88% of the eyes had a drop in IOP of 4 mmHg or more. In patients over 60 years, average intraocular pressure reduction was 9,3 mmHg and 93% of the eyes had a drop in IOP of 4 mmHg or more. The major complication in eyes with marked glaucomatous damage to their optic nerves is a possible rise in intraocular pressure following treatment. This post-laser increase in IOP was noted in 19 eyes but resolved either spontaneously or easily with medication. No visual field loss was observed in these eyes. Localized peripheral anterior synechiae were noted in 42 eyes, but these did not affect the success of the procedure.4

Adult↗
PubMed1997

[An immunohistochemical study on glycosaminoglycans distribution in the trabeculum of congenital aniridia].

Distribution of glycosaminoglycans in the trabecular tissue was immunohistochemically investigated in 7 congenital aniridia eyes of 5 patients aged 0 to 43 days. Paraffin sections of each specimen were immunohistochemically stained with antibodies to chondoroitin (clone 1-B-5), chondoroitin-1-sulfate (2-B-6), chondoroitin-6-sulfate (3-B-3), dermatan sulfate (6-B-6), and keratan sulfate (5-D-4). The trabecular meshwork and Schlemm's canal in all eyes were absent or not well differentiated. The cornea, trabecular tissue, and iris stroma were negative for chondoroitin immunostaining but positive for chondoroitin-4-sulfate, chondoroitin-6-sulfate, dermatan sulfate and keratan sulfate immunostaining. In the normal anterior segment tissue keratan sulfate is present in the cornea, trabecular tissue, and iris at the fetal stage, and disappears from the iris at the neonatal stage. These findings suggest that the persistence and/or abnormal distribution of keratan sulfate in the anterior segment may play a role in the pathogenesis of congenital aniridia.

Aniridia↗
PubMed1979

Pressure-dependent changes in nuclei and the process origins of the endothelial cells lining Schlemm's canal.

Monkeys eyes were fixed with glutaraldehyde in vivo at positive intraocular pressure of 35 or 25 mm Hg and compared with eyes fixed without a positive pressure gradient, with the use of light microscopy and transmission and scanning electron microscopy. The entire endothelial lining of the inner wall of Schlemm's canal ballooned or distended toward the external wall of the canal at positive intraocular pressure. Characteristic nuclear shapes were identified and appeared to result from the increased pressure forcing the lining away from the meshwork opposed by a restraining or anchoring effect of cytoplasmic processes attached to the subendothelial cells and trabecular meshwork. Without positive intraocular pressure endothelial cell nuclei were rounded, with many folds and notches in the nuclear membrane and were not deformed by their cytoplasmic processes. These findings suggest that the cells may be capable of elastic recoil or contraction.

Animals↗
PubMed1986

Some effects of phagocytosis on bovine meshwork cells in culture.

In this tissue-culture study, some effects of phagocytosis on the cell were investigated. Third-passage bovine trabecular-meshwork cells were incubated with latex microspheres for periods of up to 60 hr. Cells which had been involved in phagocytosis were found to settle at a faster rate than control cells, but if microspheres were added to the medium of recently settled cells, there was a reduction in their proliferative activity. Incorporation of tritiated proline remained unchanged, whereas uptake of tritiated glucosamine increased with the time period of phagocytosis. The fibronectin scaffold was more extensive and elaborate when cells were pre-incubated with microspheres before settlement. Exposure to a low concentration of microspheres promoted a higher uptake of a second presentation of 125I-labelled microspheres--an effect which was not seen if the original dose was too high.

Animals↗
PubMed1976

[Tonometry and tonography for open Schlemm's canal (author's transl)].

In 13 eyes tonometry was performed during trabeculotomy at the beginning, after preparation of the outer scleral lamella and after the excision of the outer wall of the canal of Schlemm. In 4 eyes this was combined with tonography. There was no significant change of the averaged i.o. pressure and the resistance to aqueous outflow. Thus in primary open angle glaucoma the resistance to aqueous outflow must be located primarily in the trabecular meshwork.

Glaucoma↗
PubMed1984

Influence of mercurial sulfhydryl agents on aqueous outflow pathways in enucleated eyes.

Enucleated calf and primate eyes were perfused with either p-chloromercuribenzene sulfonate (PCMBS) or p-chloromercuribenzene (PCMB). Both caused a decrease in aqueous outflow that did not result from inhibition of glycolysis in trabecular cells. Morphologic studies of PCMBS-treated primate eyes suggested that the reduction in aqueous outflow occurred as the result of cellular swelling in the trabecular meshwork and, particularly, in the juxtacanalicular connective tissue. These findings suggest that changes in cell volume may influence trabecular outflow resistance and that mercurial-sensitive membrane sulfhydryl groups could participate in the regulation of aqueous outflow.

4-Chloromercuribenzenesulfonate↗
PubMed2002

[Human trabecular cells and apoptosis: in vitro evaluation of the effect of betaxolol with or without preservative].

PURPOSE: Trabecular meshwork, which is involved in aqueous outflow resistance, is deeply modified in glaucoma patients, with a decrease in the trabecular cell number. Trabecular toxicity of antiglaucoma medications cannot be excluded. On a human cultured trabecular cell line, we investigated the potential proapoptotic effect of a beta-blocker with or without preservative, benzalkonium chloride (0.01% BAC), by flow cytometry and confocal microscopy. MATERIAL: and METHODS: A human immortalized trabecular cell line (HTM-5) obtained from a normal donor was cultured under normal conditions. Preserved 0.25% betaxolol suspension (betaxolol BAC +), unpreserved 0.25% betaxolol suspension, and 0.01% BAC were respectively added to the culture medium in a 1/10 or 1/100 dilution for 15 minutes. After a 24-hour recovery period in normal culture conditions, cell size and the expression of an apoptotic marker, Apo 2.7, were evaluated by flow cytometry and confocal microscopy. Untreated trabecular cells were used as control cells. RESULTS: Preserved and unpreserved betaxolol in a 1/10 dilution induced a significant decrease in trabecular cell size compared to controls. However, this cell size decrease was less pronounced than that induced by BAC at the same dilution. Similar results were obtained with betaxolol and BAC in a 1/100 dilution. Trabecular cell Apo 2.7 expression was significantly increased after treatment with betaxolol BAC + and BAC- in a 1/10 dilution compared to controls (36.8%, 28.1%, and 15.4%, respectively p<0.005). However, this proapoptotic activity was much less pronounced than that induced by BAC- at the same dilution (96.9%, p<10(-4)). Unpreserved betaxolol in a 1/100 dilution had no apoptotic activity on trabecular cells. Trabecular cell Apo 2.7 expression slightly increased with betaxolol BAC + at a 1/100 dilution (24.9%, p=0.04), while it was greatly increased with BAC at the same dilution (39.9%; p<10(-4)). CONCLUSION: In our model, unpreserved betaxolol at a low concentration displayed no proapoptotic activity on trabecular cells. On the other hand, preserved betaxolol displayed a moderate proapoptotic activity by triggering cell death of around 25% of cells. Trabecular cell toxicity appeared to be mainly due to the preservative benzalkonium chloride (BAC). Taken together, our results demonstrated that the strong apoptotic activity of BAC was greatly reduced within the preserved eye drops, probably through the interaction of BAC with the active compound.

Adrenergic beta-Antagonists↗
PubMed1981

The fine structure of the cribriform meshwork in normal and glaucomatous eyes as seen in tangential sections.

Electron microscopic serial sections in a tangential plane through the inner wall of Schlemm's canal and the trabecular meshwork in normal and glaucomatous eyes revealed a characteristic network of elastic-like fibers (cribriform plexus), which is directly connected to the inner wall endothelium by a special fiber system (connecting fibrils). This cribriform plexus is also connected to the ciliary muscle system. Ciliary muscle tendons were found that not only show the same fine structure as the cribriform plexus but also join it. The ciliary muscle tone can therefore directly influence the fiber system of the cribriform plexus and its connections to the inner wall of Schlemm's canal. in eyes with chronic simple glaucoma, three types of plaques in the cribriform meshwork have been described after studies of sagittal sections. A comparison with tangential sections of the same piece of tissue shows that plaques of type II and III are in fact sections through the cribriform plexus and that only type I plaques are a separate entity.

Ciliary Body↗
PubMed1987

Alteration of trabecular aqueous flow after cataract extraction.

Two human eyes that had undergone intracapsular cataract extraction were perfused with cationized ferritin. In both eyes segmental areas of trabecular meshwork collapse were demonstrated superiorly, adjacent to the cataract incision. Electron-microscopic study of these regions disclosed no labeling of the trabecular beams and trabecular spaces, suggesting impermeability to aqueous flow. In other regions, a diffuse labeling with cationized ferritin was demonstrated throughout the trabecular spaces, indicating aqueous flowthrough. Use of corneoscleral sutures may cause trabecular collapse and impermeability. When the collapse is extensive, subsequent increase in intraocular pressure may follow.

Aged↗
PubMed1982

Nonprogressive low-tension glaucoma with pigmentary dispersion.

Four patients with nonprogressive glaucomatous cupping and nonprogressive visual field damage, three of whom were referred with a diagnosis of low-tension glaucoma, were found to have slit-like radial peripheral iris transillumination defects. Three of these patients had Krukenberg spindles and dense pigmentation of the trabecular meshwork. These findings are considered pathognomonic for pigmentary glaucoma. Little is known of the natural course of this disease. A decrease in corneal and trabecular pigmentation with age and normalization of intraocular pressures after years of treatment have been noted. The patients described here were all much older than the average patient with pigmentary glaucoma, yet in none of them had a diagnosis of glaucoma been made at the time the damage presumably developed. In these patients the pigmentary glaucoma had probably remitted spontaneously.

Age Factors↗
PubMed2001

Schwalbe line's cell in the normal and glaucomatous dog.

OBJECTIVE: The canine iridocorneal angle contains an operculum, which is similar to that in nonhuman primates and consists of a peripheral extension of the inner cornea that overlies the anterior-most portion of the corneoscleral trabecular meshwork. This region contains cells, the Schwalbe line's (SL) cells, that have been found to have secretory and epithelial characteristics. This region of the iridocorneal angle represents the nonfiltering portion and becomes altered early during spontaneous glaucoma in the Beagle. The present study describes the SL cell for the first time in the dog and changes associated with canine primary open angle glaucoma. PROCEDURES: The iridocorneal angles from 18 Beagles with inherited glaucoma (3 months-8 years old) and 17 normal, age-matched Beagles were placed in 10% buffered formalin for light microscopic evaluation, or 2.5% glutaraldehyde for ultrastructural evaluation. Using at least three fields from each region of the iridocorneal angle (opercular, corneoscleral, and uveal) at x 1000 magnification, trabecular cell nuclei were counted. RESULTS: The operculum in the canine iridocorneal angle consisted of the peripheral extension of the corneal endothelium and underlying anterior-most corneoscleral meshwork, having no direct contact with the angular aqueous plexus. The SL cells associated with operculum-retained epithelial morphology (polyhedral in shape with rER, Golgi apparatus, and secretory vesicles) in both normal, pre-and early glaucomatous dogs. In animals with moderate and advanced stages the SL cells often became less epithelial and secretory in appearance. The number of SL cells in normal dogs declined by approximately one-third by the end of their first year with gradual loss thereafter. In the glaucoma group the decline was more substantial and continuous through the first three years. CONCLUSIONS: The SL cell is morphologically a distinct cell type within the canine iridocorneal angle that is specifically associated with the nonfiltering portion of the corneoscleral trabecular meshwork. Changes in the SL cells of the glaucomatous dog occurred with regard to age and progression of the disease.

Animals↗
PubMed1982

Electron microscopy of argon laser therapy in phakic open-angle glaucoma.

In 22 subjects with phakic open-angle glaucoma, trabeculectomies were performed at intervals of three hours to one year after argon laser treatment (ALT). In ten patients the ALT was done with informed consent anticipating that trabeculectomy would be performed at a scheduled time (three hours to two weeks following laser therapy). In 12 other patients, trabeculectomies were required for failure of ALT (one month to one year later). Scanning and transmission electron microscopy of the specimens examined at earlier intervals after laser therapy revealed evidence of heat effects with disruption of trabecular beams, fibrinous material, and necrosis of occasional cells, including melanin-containing endothelial cells, followed by shrinkage of the collagenous components of the trabecular meshwork. The specimens excised at longer intervals after laser treatment showed partial or total occlusion of intertrabecular spaces by a cellular layer of abnormal corneal and/or trabecular endothelial cells with widened cellular interdigitations and numerous prominent filopodial processes typical of migrating cells.

Argon↗
PubMed1991

A quantitative study of the prenatal development of the aqueous outflow system in the human eye.

There is a multiplicity of theories on the development and differentiation of the human iridocorneal angle. Many have arisen from the need to explain the pathogenesis of primary infantile (congenital) glaucoma or other related developmental disturbances. The present study, which is the first light and electron microscopical morphometric analysis of human fetal eyes, was designed to determine the nature of the changes in various tissue components during trabecular anlage formation and differentiation (between 12 and 22 weeks of gestation). The results demonstrate that the trabecular anlage doubles in cross-sectional area during this period. However, when circumferential growth is considered there is in fact a threefold increase in anlage volume. Cell density in sections decreases over the 10-week period, as does the number of cells per unit volume. However, employment of stereological analysis together with corrections for volume changes revealed a two to threefold increase in absolute number of cells per eye (2.8 x 10(5) to 7.5 x 10(5)). Relative and absolute volume data on the four major constituents of the trabecular anlage show that extracellular matrix increases in the most significant and predictable fashion (360% in absolute volume), with the increase in intertrabecular spaces being more variable (200%). The findings are discussed in relation to previous theories of trabecular meshwork development.

Aqueous Humor↗
PubMed2001

Gonioscopic changes after implantation of a posterior chamber lens in phakic myopic eyes.

PURPOSE: To evaluate the effects of posterior chamber implantation of phakic intraocular lenses on angle structures and the correlation with intraocular pressure (IOP). SETTING: Department of Ophthalmology, University Hospital of Vienna, Vienna, Austria. METHODS: A Staar implantable contact lens (ICL) was implanted in 20 white patients (34 eyes) with high myopia. The patients were followed for a mean of 2.3 years (range 0.8 to 6.0 years). Two subgroups were created: One had a follow-up of 2.4 to 6.0 years and the other, 0.8 to 2.3 years. The mean spherical power of the implanted ICL was -16.8 diopters (D) (range -9.0 to -21.0 D). The angle structures were examined by gonioscopy using the Spaeth technique, and optical pachymetry and IOP were measured in dilated and undilated pupils. Trabecular pigmentation was measured semiquantitatively. The ICL models included a few prototypes (6 eyes), the V2 model (10 eyes), the V3 model (6 eyes), and the V4 model (12 eyes). RESULTS: The anterior chamber angle was between 11 and 20 degrees in 41% of eyes, between 21 and 30 degrees in 21%, larger than 30 degrees in 21%, and 10 degrees or smaller in 17%. An apparent iris root insertion was above Schwalbe's line in 6% of eyes, behind Schwalbe's line in 12%, at the scleral spur in 67%, and in a deep angle recess behind the scleral spur in 15%. The curvature of the iris was regular in 19 eyes and steep in 15 eyes. The mean pigmentation in all 4 quadrants was 1.3. (Grade 1 was defined as trace pigmentation.) The mean pachymetry from the endothelium to the ICL anterior surface was 2.7 mm and from the endothelium to the anterior surface of the crystalline lens, 3.2 mm. The mean IOP was 14.1 mm Hg in undilated pupils and 12.1 mm Hg in dilated pupils. There was no correlation between angle pigmentation and IOP. CONCLUSION: Trace pigmentation in the trabecular meshwork was common after ICL implantation. However, there was no direct influence on IOP. Long-term follow-up is necessary to evaluate the effect and progress of trabecular pigmentation in eyes with an ICL.

Adult↗
PubMed1980

Presence of lysosomal hyaluronidase in human corneoscleral tissue.

Hyaluronidase activity in human corneoscleral tissues was biochemically studied. The corneoscleral junction, particularly the inner layer, showed higher activity than other corneoscleral tissues. The possible role of lysosomal hyaluronidase in the trabecular meshwork is discussed.

Adult↗
PubMed1990

The effect of prostaglandin F2 alpha on trabecular outflow facility in cynomolgus monkeys.

Cynomolgus monkeys were treated topically in one eye with 2 micrograms of prostaglandin F2 alpha -l-isopropylester (PGF2 alpha-IE) twice daily. On day 4, 3 hr after the seventh dose, intraocular pressure (IOP) was 8.1 +/- 0.7 mmHg lower in the treated than in the control eyes. On day 5, after the ninth PGF2 alpha dose, gross facility was measured in both eyes by determining the rate of fluid flow from an external reservoir into the eye at two different IOP levels. Simultaneously, trabecular facility was measured by determining the rate of accumulation of intracamerally infused radioiodinated albumin in the general circulation. Gross facility was 40-60% higher in PGF2 alpha treated than in control eyes, but there was no difference in trabecular facility. The increase in gross facility sometimes reported following PGF2 alpha probably represents increased pseudofacility or uveoscleral facility, rather than true facility of outflow through the trabecular meshwork and Schlemm's canal.

Animals↗
PubMed1978

Pathophysiology and electron microscopy of melanomalytic glaucoma.

We examined an eye with melanomalytic glaucoma by quantitative aqueous perfusion, light and electron microscopy. Facility of outflow was markedly diminished from normal in vivo and in vitro. The trabecular meshwork was heavily laden on its surface and in the intertrabecular spaces with macrophages. Many of these cells appeared to be wandering macrophages, while some appeared to be detached, phagocytic trabecular endothelial cells.

Aqueous Humor↗
PubMed1998

The study on culture and ultrastructure of glaucomatous trabecular cells in vitro.

PURPOSE: To establish the culture system of human glaucomatous trabecular cells in vitro and study their ultrastructures. METHODS: The trabecular specimens from trabeculectomy were cultured in vitro and passaged 3 times, then identified. Moreover, the glaucomatous cells were observed with electron microscope while compared with the normal ones. RESULTS: Cultured human glaucomatous trabecular cells were obtained. The ultrastructure of the cells showed the decrease in vilious project, coated vesicle and lysosomal inclusion. CONCLUSION: The establishment of human glaucomatous trabecular cells culture in vitro made the culture system more perfect. The morphologic changes might be related to the abnormal functions of human trabecular meshwork cells.

Cell Division↗