Cell and protein adhesion studies in glaucoma drainage device development. The AGFID project team. (1/95)

AIM: To examine in vitro whether phosphorylcholine coating of poly(methylmethacrylate) can reduce the adhesion of fibrinogen, fibrin, human scleral fibroblast and macrophage compared with current biomaterials used in the construction of glaucoma drainage devices. METHODS: Sample discs (n=6) of poly(methylmethacrylate), silicone, polypropylene, PTFE, and phosphorylcholine coated poly(methylmethacrylate) were seeded with fibrinogen, fibrin, fibroblast, and macrophages and incubated for variable lengths of time. The quantification was performed using radioactivity, spectrophotometry, ATP dependent luminometry, and immunohistochemistry respectively. RESULTS: Fibrinogen and fibrin adhesion to phosphorylcholine coated poly(methylmethacrylate) were significantly lower than PMMA (p=0.004). Phosphorylcholine coating of poly(methylmethacrylate) also significantly reduced the adhesion of human scleral fibroblast (p=0.002) and macrophage (p=0.01) compared with PMMA. All the other biomaterials showed either similar or insignificantly different levels of adhesion to all the proteins and cells tested compared with PMMA. CONCLUSION: Phosphorylcholine coating is a new material technology that offers considerable promise in the field of glaucoma drainage device development.  (+info)

Efficacy and safety of the Ahmed glaucoma valve implant in Chinese eyes with complicated glaucoma. (2/95)

AIMS: To evaluate the efficacy and safety of the Ahmed glaucoma valve implant in Chinese eyes with complicated glaucomas. METHODS: This retrospective study reviewed the final intraocular pressure, visual outcome, and incidence of complications in all patients with the Ahmed glaucoma valve implant performed at the Prince of Wales Hospital, Hong Kong, between June 1996 and November 1998. RESULTS: A total of 65 eyes from 60 patients were treated with the Ahmed glaucoma implant. At a mean follow up (SD, median) of 21.8 (9.2, 28. 0) months (range 6-37 months), the mean intraocular pressure was reduced from 37.0 (SD 12.1) mm Hg before the implant surgery to 16.1 (12.4) mm Hg at the last follow up after surgery. The success rate of intraocular pressure control of <22 mm Hg was achieved in 73.8% of operated eyes. Transient postoperative hypotony with shallow anterior chamber occurred in 10.8% of cases. The most common postoperative complication was the formation of encapsulated bleb (24.6%). CONCLUSIONS: The Ahmed glaucoma valve implant appears to be effective and relatively safe for treating complicated glaucomas in Chinese eyes. The success rate is comparable with those reported in non-Asian eyes. Formation of postoperative encapsulated bleb is, however, more commonly encountered.  (+info)

Plain film imaging of Baerveldt glaucoma drainage implants. (3/95)

A glaucoma drainage implant was detected on plain skull radiographs before MR imaging examination of the brain. The patient was denied the MR imaging for fear of dislodging the "metallic foreign body." The Baerveldt glaucoma drainage implant was mistakenly identified as an orbital metallic object based on its radiographic characteristics. Because none of the current glaucoma drainage implants contain ferromagnetic material, patients with these devices can undergo MR imaging without special precaution.  (+info)

Combined extracapsular cataract extraction with ahmed glaucoma valve implantation in phacomorphic glaucoma. (4/95)

PURPOSE: To report a retrospective analysis of a combined procedure of extracapsular cataract extraction (ECCE) with heparin surface modified (HSM) posterior chamber intraocular lens (PCIOL) implantation along with primary Ahmed glaucoma valve (AGV) implantation in an attempt to optimize visual acuity gains and intraocular pressure (IOP) control in patients with phacomorphic glaucoma. METHODS: ECCE with HSM PC IOL and AGV implantation was performed through two separate incisions in 15 patients diagnosed with phacomorphic glaucoma. Postoperative improvement in visual acuity and IOP control were monitored. RESULTS: A steady control of IOP was maintained in all patients with minimum anti-glaucoma medications. The average visual acuity was approximately 6/24 at 3 months. CONCLUSION: Superior preoperative IOP control and a shorter phacomorphic attack resulted in better postoperative vision. The successful maintenance of IOP within the desired range in this study suggests that the procedure should be performed under similar conditions.  (+info)

Clinical experience of e-PTFE membrane implant surgery for refractory glaucoma. (5/95)

AIMS: To evaluate the clinical efficacy of membrane tube implant made of expanded polytetrafluoroethylene (e-PTFE, Gore-Tex) membrane and silicone tube in treating refractory glaucoma. METHODS: A retrospective chart review was performed on 43 eyes of 40 patients who underwent glaucoma tube shunt implant surgery using double layered e-PTFE membrane and silicone tube to treat refractory glaucoma. The surgeries were performed from May 1991 to September 1995, and the subjects were patients with terminal glaucoma without useful vision on the study eye. RESULTS: The mean follow up period was 32.9 months. The Kaplan-Meier survival for intraocular pressure (IOP) control (IOP between 6 and 21mm Hg without significant complication) was 80.9% at 1 year, 73.9% at 2 years, and 62.2% at 3 years after surgery. After excluding three eyes of three patients who were dropped within 3 months after surgery and did not have any serious complication or problem in IOP control, the average preoperative IOP was 42.5 (SD 14.6) mm Hg and IOP on the last visit was 17.3 (10.2) mm Hg (p = 0.000, n = 40). The number of antiglaucoma medications before surgery (2.2 (0.6)) was reduced to 0.5 (0.8) on the last visit (p = 0.000). The IOP was controlled within the range of 6-21 mm Hg in 26 eyes (65.0%). In the remaining 14 eyes (35%), we could not control the IOP or additional surgery was needed to control the IOP or to treat severe complications. Two cases of endophthalmitis and three of phthisis were found as serious complications. The other complications were similar to those of other commercially available glaucoma implants. CONCLUSION: A comparable clinical result was obtained with this new implant as with the other commercially available implants. This implant with a thin and non-rigid reservoir has a potential to reduce some complications associated with the large volume and rigid consistency of the other implants, although it is not yet proved. This membrane tube implant may be considered as another substitute in the surgery of refractory glaucoma.  (+info)

A prospective randomised trial of viscocanalostomy with and without implantation of a reticulated hyaluronic acid implant (SKGEL) in open angle glaucoma. (6/95)

AIM: To prospectively assess the efficacy and complications of viscocanalostomy with a reticulated hyaluronic acid implant (VSRHAI) versus standard viscocanalostomy in patients with medically uncontrolled open angle glaucoma. METHODS: A consecutive series of 40 patients (40 eyes) with uncontrolled open angle glaucoma underwent non-penetrating antiglaucomatous surgery. After the excision of the deep scleral flap they were randomly assigned to either a standard viscocanalostomy or additional implantation of a reticulated hyaluronic acid implant. Follow up visits were over a period of 12 months after surgery. RESULTS: The mean preoperative intraocular pressure (IOP) was 26.5 (SD 6.1) mm Hg for all patients enrolled. The mean IOP was 8.1 (SD 5.6) mm Hg 1 day after surgery for the viscocanalostomy group (p<0.001) and 12.0 (SD 5.2) mm Hg for the VSRHAI group (p<0.001). The postoperative IOP difference between the two groups was statistically significant (p = 0.03). The success rate, defined as an IOP lower than 22 mm Hg without medication, was 40% in both groups at 12 months postoperatively (p = 0.90). The number of postoperative complications was equally low for both groups. CONCLUSIONS: Both surgical procedures, viscocanalostomy and VSRHAI, provide comparable success rates over a 1 year follow up period. The specific intraoperative and postoperative complications of non-penetrating surgery were seen in our series, although the overall rate of postoperative complications proved equally low for both techniques.  (+info)

Partial Tenon's capsule resection with adjunctive mitomycin C in Ahmed glaucoma valve implant surgery. (7/95)

AIM: To verify if partial intraoperative Tenon's capsule resection (PTCR) with adjunctive mitomycin C is effective in developing thin, avascular blebs in eyes undergoing Ahmed glaucoma valve insertion, and to assess the efficacy and safety of this procedure. METHODS: A multicentre, prospective, alternating case assignment, investigator unmasked, parallel group, comparative interventional study was conducted in four Latin American countries (Argentina, Brazil, Colombia, and Peru). Ahmed glaucoma valve implant insertion with PTCR (group A) and without PCTR (group B) was performed in neovascular glaucomatous eyes without previous surgery. Adjunctive mitomycin C (MMC) was used in both groups. Patients were examined 1 day, 10 days, 1 month, 2 months, 3 months, 6 months, and 1 year following the surgery. Intraocular pressure (IOP) and the appearance of the bleb were evaluated at each examination. Appearance of the bleb was classified at both the 1 month mark and last examinations into one of three groups: flat and vascularised; elevated avascular; or elevated and not avascular. RESULTS: 92 eyes from 92 patients were included in the study. The preoperative mean IOP was 50.0 (SD 10.5) mm Hg in group A and 48.4 (11.7) in group B (p>0.05). Statistically significant IOP reductions were observed at all periods of follow up. 12 months after surgery, the mean IOP was 17.2 (5.0) mm Hg in group A and 18.3 (8.7) mm Hg in group B (p>0.05). A hypertensive phase occurred in 40.0% in group A and in 46.8% in group B (p>0.05). At the 1 month and the final follow up, the blebs in all eyes were considered elevated and not avascular. The success rate (IOP0.05). Overall, 74.2% of the patients achieved an IOP +info)

Aqueous dynamic and histological findings after deep sclerectomy with collagen implant in an animal model. (8/95)

AIM: The use of an animal model to study the aqueous dynamic and the histological findings after deep sclerectomy with (DSCI) and without collagen implant. METHODS: Deep sclerectomy was performed on rabbits' eyes. Eyes were randomly assigned to receive collagen implants. Measurements of intraocular pressure (IOP) and aqueous outflow facility using the constant pressure method through cannulation of the anterior chamber were performed. The system was filled with BSS and cationised ferritin. Histological assessment of the operative site was performed. Sections were stained with haematoxylin and eosin and with Prussian blue. Aqueous drainage vessels were identified by the reaction between ferritin and Prussian blue. All eyes were coded so that the investigator was blind to the type of surgery until the evaluation was completed. RESULTS: A significant decrease in IOP (p<0.05) was observed during the first 6 weeks after DSCI (mean IOP was 13.07 (2.95) mm Hg preoperatively and 9.08 (2.25) mm Hg at 6 weeks); DS without collagen implant revealed a significant decrease in IOP at weeks 4 and 8 after surgery (mean IOP 12.57 (3.52) mm Hg preoperatively, 9.45 (3.38) mm Hg at 4 weeks, and 9.22 (3.39) mm Hg at 8 weeks). Outflow facility was significantly increased throughout the 9 months of follow up in both DSCI and DS groups (p<0.05). The preoperative outflow facility (OF) was 0.15 (0.02) micro l/min/mm Hg. At 9 months, OF was 0.52 (0.28) microl/min/mm Hg and 0.46 (0.07) micro l/min/mm Hg for DSCI and DS respectively. Light microscopy studies showed the appearance of new aqueous drainage vessels in the sclera adjacent to the dissection site in DSCI and DS and the apparition of spindle cells lining the collagen implant in DSCI after 2 months. CONCLUSION: A significant IOP decrease was observed during the first weeks after DSCI and DS. DS with or without collagen implant provided a significant increase in outflow facility throughout the 9 months of follow up. This might be partly explained by new drainage vessels in the sclera surrounding the operated site. Microscopic studies revealed the appearance of spindle cells lining the collagen implant in DSCI after 2 months.  (+info)