Surgical vs medical management of chronic open-angle glaucoma.
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Chronic Disease↗
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Results for “Filtering Surgery”
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Histopathologic and immunohistochemical analysis of the filtration bleb after unsuccessful glaucoma seton implantation.
PURPOSE: To analyze histopathologically and immunohistochemically the filtration bleb after unsuccessful glaucoma seton implantation. METHODS: A von Denffer implant and two Molteno implants that were nonfunctional at three months, at 11 months, and at five years after implantation, respectively, were compared by evaluating the adjacent bleb with light microscopy and a panel of 11 antibodies to epithelial, mesenchymal, and inflammatory cells. RESULTS: The wall of the filtration bleb three months after implantation consisted of loosely arranged collagenous connective tissue with relatively abundant fibroblasts labeled with monoclonal antibodies (MAbs) V9 and Vim 3B4 to vimentin. At 11 months and at five years, the collagenous layers had become increasingly thick and the fibroblasts scarce. All blebs showed metaplastic myofibroblasts surrounded by tenascin, as identified by MAb 1A4 to alpha-smooth muscle actin and TN2 to tenascin, respectively. One bleb was lined by a monolayer of cells that reacted with MAb CAM 5.2 and CY-90 to cytokeratin 8 and 18, respectively, and was apparently derived from the identically reacting proliferating corneal endothelial cells. Another bleb harbored many macrophages and foreign-body giant cells. Little evidence of chronic inflammation around the seton was detected. CONCLUSIONS: A glaucoma seton may induce several processes that potentially decrease filtration. In addition to formation of a collagenous cyst, presence of myofibroblasts suggests long-standing scar modulation that potentially leads to compaction of the filtration membrane. Furthermore, macrophages and corneal endothelial cells may invade the filtration bleb.
Adult↗
Histology and mechanism of filtering operations.
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Eye↗
The treatment of normal-tension glaucoma.
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Carbonic Anhydrase Inhibitors↗
Pars plana filtration with multiple laser perforation of the uvea for neovascular glaucoma following proliferative diabetic retinopathy.
PURPOSE: To evaluate the effect of pars plana filtration with multiple laser perforation of the uvea in neovascular glaucoma patients following proliferative diabetic retinopathy. METHODS: In 18 eyes of 13 patients, after a fornix-based conjunctival incision, two 9 x 3 mm, thin, rectangular scleral flaps were created 3-6 mm posterior to the limbus. The remaining layers of sclera under each flap were removed. The exposed uvea was irradiated at a mean of 60.6 spots with an argon laser just to the point of perforation. After the posterior chamber fluid escaped, the flaps were sutured. RESULTS: The mean preoperative intraocular pressure (IOP) was 36.4 +/- 9.0 mm Hg. After an average follow-up of 16.6 +/- 5.9 months, the mean final postoperative IOP was 16.6 +/- 4.4 mm Hg. The postoperative IOP was below 21 mm Hg in 3 (16.7%) of the 18 eyes without medication, in 14 (77.8%) on anti-glaucoma eye drops, and in 16 (88. 9%) on anti-glaucoma eye drops and an oral carbonic anhydrase inhibitor. Snellen visual acuity improved by more than 2 lines in 7 of the 18 eyes, worsened by this amount in 3, and remained within baseline +/- 2 lines in 8. CONCLUSION: This procedure is an effective treatment for neovascular glaucoma patients following proliferative diabetic retinopathy.
Acetazolamide↗
Autologous conjunctival resurfacing of leaking filtering blebs.
PURPOSE: To present a case series of a new technique to repair late bleb leaks. DESIGN: Retrospective, noncomparative, consecutive case series. PARTICIPANTS: Forty-seven autologous conjunctival resurfacings of late bleb leaks were performed by four surgeons at two institutions. METHODS: Autologous conjunctival grafts were placed over existing de-epithelialized leaking blebs. MAIN OUTCOME MEASURES: Leak-free, Seidel-negative blebs and controlled glaucoma. RESULTS: After a mean follow-up of 14 +/- 12 months, one patient continued to have bleb leak at the last follow-up, and one frank leak resolved with aqueous suppression. Intraocular pressure increased from 6.6 +/- 4.4 mmHg (0.13 glaucoma medications) to 11.9 +/- 4.1 mmHg (0.41 glaucoma medications). CONCLUSIONS: Conjunctival resurfacing with autologous tissue is an effective technique to repair late bleb leaks.
Adolescent↗
Cyclophotocoagulation: a report by the American Academy of Ophthalmology.
OBJECTIVE: This document describes cyclophotocoagulation procedures for glaucoma and examines the evidence to answer key questions about patient selection, and efficacy of transscleral and endoscopic techniques. METHODS: A literature search conducted for the years 1968 to 2000 retrieved 130 citations. The author reviewed 34 of these articles and selected 19 for the panel methodologist to review and rate according to the strength of evidence. A Level I rating is assigned to properly conducted, well-designed, randomized clinical trials; a Level II rating is assigned to well-designed cohort and case-control studies; and a Level III rating is assigned to case series and poorly designed prospective and retrospective studies, including case-control studies. RESULTS: The predominant problem with all studies on cyclophotocoagulation is the lack of a uniform definition of success, which makes comparisons difficult. One randomized controlled trial (Level I evidence) compared the efficacy of transscleral cyclophotocoagulation with noncontact Nd:YAG and semiconductor diode laser. It found no significant difference between the two, although a significant problem was the variability allowed with laser parameters. Most of the literature consists of noncomparative case series that provide evidence that is limited and often not convincing. CONCLUSION: Cyclophotocoagulation is indicated for patients with refractory glaucoma who have failed trabeculectomy or tube shunt procedures, patients with minimal useful vision and elevated intraocular pressure, and patients who have no visual potential and need pain relief (based on Level III evidence). It may be useful for patients whose general medical condition precludes invasive surgery or who refuse more aggressive surgery (i.e., filter or tube). It is also useful in emergent situations, such as the acute onset of neovascular glaucoma. There is insufficient evidence to definitively compare the relative efficacy of the cyclophotocoagulation procedures for glaucoma. It is the panel's opinion, however, that semiconductor diode systems appear to possess the best combination of effectiveness (based on Level III evidence), portability, expense, and ease of use at this time.
Academies and Institutes↗
Effects of viscoelastic injection into Schlemm's canal in primate and human eyes: potential relevance to viscocanalostomy.
OBJECTIVE: To study possible initial mechanisms of alterations in aqueous outflow that may result from the injection of viscoelastic into Schlemm's canal (SC) during viscocanalostomy. DESIGN: Experimental animal (Macaca nemestrina) and human autopsy study. METHODS: Eyes were dissected into a limbal ring and hemisected or quartered. Uncannulated segments served as controls. In treated segments, SC was cannulated and viscoelastic injected. Segments were fixed and sectioned into continuous 500 to 1000 microm pieces, examined at the dissecting microscope, and photomicrographs were taken. Representative tissue was further prepared for scanning electron microscopy or sectioned at 1 microm. MAIN OUTCOME MEASURES: Tissue sections were examined to determine the extent of dilation and disruption of SC and related structures. SC dimensions were measured in segments from controls, cannulated regions, and regions of viscoelastic injection beyond the cannula insertion. In the hemisected segments, the circumferential extent of SC dilation was determined, and structures within the canal were described and counted. RESULTS: SC was dilated with increased anteroposterior length and height in cannulated and viscoelastic-injected segments in both primate and human eyes relative to untreated controls. The walls of SC were disrupted in both regions of cannulation and of viscoelastic injection, and the collector channels were widely dilated by viscoelastic. With decreasing effectiveness, the injected viscoelastic circumferentially dilated SC as far as 14 mm and 16 mm in primate and human hemisections, respectively. Structures that bridged between the walls of SC were often disrupted. CONCLUSIONS: Cannulation of SC and injection of viscoelastic beyond the cannula resulted in marked dilation of SC and associated collector channels. Lateral walls, inner wall endothelium, and bridging structures of SC were frequently disrupted by cannulation and sometimes by injected viscoelastic. These findings suggest that viscocanalostomy may acutely cause a direct communication between SC and the juxtacanalicular space, and so may initially enhance conventional aqueous outflow. Controlled clinical trials will be necessary to determine the long-term outcomes of this procedure.
Aged↗
Changes in optic nerve head blood flow after therapeutic intraocular pressure reduction in glaucoma patients and ocular hypertensives.
PURPOSE: To detect and quantify changes in optic nerve head (ONH) and peripapillary retinal blood flow by scanning laser Doppler flowmetry (SLDF) in open-angle glaucoma (OAG) and ocular hypertension (OHT) after therapeutic intraocular pressure (IOP) reduction. DESIGN: Prospective, nonrandomized, self-controlled trial. PARTICIPANTS: Twenty patients with OAG and 20 patients with OHT with clinical indications for therapeutic IOP reduction were prospectively enrolled. INTERVENTION: IOP reduction was achieved by medical, laser, or surgical therapy. All patients had IOP reductions more than 20% and a minimum of 4 weeks follow-up. MAIN OUTCOME MEASURES: Blood flow measurements were performed by SLDF analysis software (version 3.3) using Heidelberg Retina Flowmeter images. Statistical evaluations were performed on both groups using a two-tailed distribution paired t test. RESULTS: Twenty patients with OAG had a mean IOP reduction of 37% after treatment. In these patients, mean (+/- standard deviation) rim blood flow increased by 67% (from 158 +/- 79 arbitrary units to 264 +/- 127 arbitrary units, P = 0.001), whereas mean temporal peripapillary retinal flow decreased by 7.4% (P = 0.24), and mean nasal peripapillary retinal flow increased by 0.3% (P = 0.96). Twenty OHT patients had a mean IOP reduction of 33% after treatment. In contrast to the OAG group, neither the mean rim blood flow (7.5% increase from 277 +/- 158 arbitrary units to 298 +/- 140 arbitrary units, P = 0.41) nor the mean temporal (P = 0.35) or nasal (P = 0.88) peripapillary retinal flow changed significantly. CONCLUSIONS: For a similar percentage of IOP reduction, OAG patients had a statistically significant improvement of blood flow in the neuroretinal rim of the ONH, whereas OHT patients did not demonstrate such a change. Peripapillary retinal blood flow, expected to be affected less in glaucoma, remained stable in both groups. In addition to indicating a response to therapy in OAG patients, the reported changes in rim perfusion suggest that ONH autoregulation may be defective in OAG while intact in OHT.
Adult↗
Expression of inflammatory membrane markers by conjunctival cells in chronically treated patients with glaucoma.
PURPOSE: Recent histologic studies of conjunctival tissues in patients who have had long-term treatment for glaucoma have shown in situ an abnormal infiltration by inflammatory cells. In this study, conjunctival inflammatory antigens were investigated in impression cytology specimens from patients who have been and those who have not been treated for glaucoma. METHODS: This study included 107 eyes from 55 patients with primary open-angle glaucoma. Of these, 48 had received prolonged topical treatments, all containing benzalkonium chloride as a preservative. Seven glaucomatous eyes could be examined before any treatment. In addition, the authors examined 11 patients (21 eyes) receiving anticataract eye drops preserved with chlorhexidine and 15 normal untreated subjects (30 eyes). In all patients, immunocytochemistry was performed in impression cytology specimens, using two monoclonal antibodies against HLA-DR antigens and receptor to IgE CD23. RESULTS: None of the untreated eyes showed reactivity for either monoclonal antibody. In contrast, HLA-DR expression by conjunctival cells was found in 43 of 88 treated eyes (mean percentage of reactive cells, 70% +/- 28%) and positive staining for receptor to IgE in 26 of 68 eyes (52% +/- 28% of conjunctival cells). Results were not related to a specific treatment or combination of anti-glaucoma drugs. However, the proportion of positive specimens (3/14 for both antigens) in the group receiving chlorhexidine-containing eye drops was significantly lower than that found in the patients with glaucoma. CONCLUSION: This study showed abnormal expression of inflammatory markers without clinical inflammation at the level of conjunctival cells in repetitive contact with various anti-glaucomatous treatments and their common preservative, benzalkonium chloride. Failure in filtering glaucoma surgery was found to be related to prolonged medical treatment; therefore, a topical sensitization to preservatives and/or anti-glaucoma drugs has been hypothesized. An immunocytologic test thus could be useful for qualitative and quantitative investigation of drug-induced conjunctival inflammation and predict high-risk patients.
Adrenergic beta-Antagonists↗
Remodeling filtering blebs with the neodymium:YAG laser.
PURPOSE: To describe a new method of treating large, overfiltering, leaking blebs using a continuous-wave neodymium:YAG laser. METHODS: Twenty-three eyes of 23 patients underwent YAG laser remodeling because of overfiltration and hypotony (group 1; n = 14); leaking bleb and hypotony (group 2; n = 5); and large, irritating bleb (group 3; n = 4). Using a neodymium:YAG laser in the continuous-wave multimode, a grid pattern of laser treatment was placed over the entire bleb using energy levels between 3.0 and 4.0 J and a laser offset between 0.9 and 1.2 mm. A torpedo patch then was placed directly over the bleb for 48 hours. Steroid therapy was avoided. RESULTS: In group 1, 64% of eyes had an intraocular pressure increase of at least 3.0 mmHg. In group 2, 80% of bleb leaks were sealed. In group 3, 100% of patients had resolution of their discomfort. The elevation in intraocular pressure peaked at 1 to 3 months and diminished thereafter. There was improvement in vision of at least two Snellen acuity lines in 52% of eyes. Complications included the need for laser retreatment (7 eyes), creation of temporary bleb leak by the YAG laser (2 eyes), transient increase in intraocular pressure (2 eyes), and corneal edema (1 eye). CONCLUSION: The continuous-wave neodymium:YAG laser can be used to effectively change the appearance and behavior of filtering blebs, although the duration of treatment effect is unknown.
Adult↗
Encapsulated filtering blebs.
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Filtering Surgery↗
Formula revealed.
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Antibiotics, Antineoplastic↗
In vitro flow testing of glaucoma drainage devices.
OBJECTIVE: The study was intended to determine methods that could evaluate in vitro the flow characteristics of glaucoma drainage devices. DESIGN: Two test methods were used: (1) a gravity-driven flow test and (2) a syringe-pump-driven flow test. Eighteen devices, both valved and nonvalved, from 4 manufacturers were evaluated for their hydrodynamic resistance and the pressure at which the flow becomes 0. OUTCOME: Results show a wide variation in device performance, indicating a strong need for enhanced quality control procedures in the device manufacturing process. CONCLUSION: A gravity-driven flow test provides a reasonably quick test of both resistance and closing pressure, which might be useful as a manufacturing line test. The syringe-driven flow test requires more time but provides additional insight into device performance, and, therefore, might be useful as a design validation test.
Drainage↗
Needling revision of glaucoma drainage device filtering blebs.
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Chemotherapy, Adjuvant↗
Role of ultrasound biomicroscopy in managing pseudophakic pupillary block glaucoma.
We describe a case of anterior capsule adherence to the iris that occurred after phacoemulsification with in-the-bag intraocular lens (IOL) implantation. This adherence led to the development of pseudophakic pupillary block glaucoma. There were no synechias at the pupillary margin associated with the capsule-iris adherence. Ultrasound biomicroscopy, used to evaluate the anterior segment in vivo, clarified the mechanism of pseudophakic pupillary block. The pupillary block was relieved by a single laser iridotomy.
Aged↗