Failed Blebs Research Articles

Histopathological findings of failed blebs after microinvasive bleb surgery with the XEN Gel Stent and Preserflo MicroShunt

PurposeThe success of XEN Gel Stent (XEN) and Preserflo MicroShunt (Preserflo) implantation depends mainly on the development of bleb fibrosis. This study aimed to describe the histological findings of bleb fibrosis after XEN and Preserflo surgery.MethodsThis retrospective study included patients with different types of glaucoma who underwent revision surgery after XEN or Preserflo implantation. The available clinical information and histological samples of removed fibrotic tissue were analyzed.ResultsThirty-six patients were included. Revision surgery was performed at a median of 195 (range = 31–1264) days after primary surgery. The mean intraocular pressure changed from 29.1 (± 10.3) mmHg at baseline to 18.3 (± 8.7) mmHg (− 37%; p < 0.0001) and 16.2 (± 4.2) mmHg (− 45%; p < 0.0001) after 6 and 12 months, respectively. Histological analysis revealed an increase in activated fibroblasts and macrophages in all specimens and a parallel orientation of fibroblasts in a minor part of the probe in 60% of the specimens. No pronounced inflammatory reaction in the form of lymphocytic or granulocytic infiltration was observed. The comparison of specimens from uveitic glaucoma and primary open-angle glaucoma patients revealed no significant differences.ConclusionsThe histological analysis of fibrotic blebs from the XEN and Preserflo implants did not show any pronounced immune or foreign-body reaction and revealed a similar histological pattern of failed blebs after trabeculectomy.

Predictive Value of Bleb Vascularity after Mitomycin C Augmented Trabeculectomy.

Background: To evaluate the relationship between bleb vascularity and surgical outcome one year after mitomycin C (MMC) augmented trabeculectomy. Methods: This was a prospective study of 51 eyes of 44 patients after MMC-augmented primary trabeculectomy with follow-up of 12 months. The total vessel area of a bleb was measured with ImageJ software on color photographs of the bleb on day 1 and 14, then months 1, 3, 6 and 12 after trabeculectomy. Blebs were classified clinically as successful (intraocular pressure (IOP) ≤ 18 mmHg and a >30% reduction in IOP without antiglaucoma medications or additional surgical interventions) or failed. Linear regression analysis was performed to determine the correlation of bleb vascularity with IOP and outcome. Results: At 1 year, 40 eyes (78.4%) were classified as successful and 11 eyes (21.6%) as failed. The mean bleb vascularity at 1, 3 and 12 months after surgery was significantly higher in failed blebs (16.31% vs. 13.01%, p = 0.005, 14.93% vs. 10.15%, p = 0.001, 8.99% vs. 6.37%, p = 0.011, respectively). There were no significant differences in mean bleb vascularity at 1 and 14 days postoperatively in successful and failed blebs. The results revealed a significant association between vessel area at 1 and 3 months after trabeculectomy with IOP at 6 months postoperatively (p = 0.005 and p = 0.009, respectively). Conclusions: In this prospective study, we demonstrated a strong relationship between bleb vascularity and the surgical outcomes of trabeculectomy. Vascularity of the filtering bleb during early postoperative period was not correlated with IOP or success of trabeculectomy at one year. Increased bleb vascularity 1, 3 and 12 months after trabeculectomy appears to predict surgical failure at 1 year after trabeculectomy.

Role of Bleb Needling in Rescuing Failing Blebs - A Review

Bleb failure is one of the common complications of trabeculectomy surgery. The treatment of failed bleb involves a second trabeculectomy procedure, an implant surgery or restarting the patient on medications. Bleb needling is a procedure that if done correctly, can revive a failing bleb and also negate the need to do a repeat procedure in a less interventional fashion. Hence, the knowledge of this procedure is essential for a clinician to manage cases of bleb failure that present routinely in outpatient department. This article entails various aspects of bleb needling procedure, its method, indications and literature review.

Correlation between morphologic appearance and function of filtering bleb in vivo.

Efficacy and long-term success of trabeculectomy largely depends on the postoperative development of a functioning filtering bleb. This study was designed to observe histological changes in filtering blebs after trabeculectomy using in vivo confocal microscopy (IVCM), and to investigate the correlation between morphologic appearance and function of filtering blebs. A total of 46 glaucoma patients who had received a trabeculectomy unilaterally in the past 1 to 60 months underwent slit-lamp examination, applanation tonometry, and in vivo confocal microscopy. Eyes were classified into 4 groups according to the morphologic appearance of the filtering bleb based on the Kronfled system: type I blebs (8 eyes), type II blebs (14 eyes), type III blebs (16 eyes), and type IV blebs (8 eyes). The IVCM images were analyzed for the number of intraepithelial microcysts, the density of subepithelial connective tissue and the presence of blood vessels. Type II blebs presented with numerous intraepithelial vacuolar microcysts, while several large intraepithelial microcysts were found in type I blebs. Subepithelial connective tissue was widely spaced in type I and II blebs. In contrast, type III and IV blebs showed few or no intraepithelial microcysts, and subepithelial connective tissue was densely distributed. Neovascularization was seen in 83.3% of failed blebs, whereas neovascularization was found in only 16.6% of successful blebs. Different types of blebs reveal various histological characteristics at the cellular level, which appear to be correlated with postoperative filtering function.

Filtering blebs functionality after trabeculectomy: a clinical and in vivo confocal microscopy study

AbstractPurpose To evaluate macroscopic and microscopic morphological features of filtering blebs after trabeculectomy with Mitomycin C (MMC) or 5‐Fluorouracil (5‐FU) and correlate them with function.Methods Retrospective case control study of 28 eyes (21 patients) submitted to trabeculectomy (15 with MMC and 13 with 5‐FU) and 11 eyes (10 patients) treated medically. Ophthalmologic examinations included Goldmann applanation tonometry, slit‐lamp examination and photography (Moorfields bleb grading system classification) and in vivo confocal microscopy (Heidelberg Retina Tomograph II, Rostock Cornea Module). Eyes were classified into 3 groups: control, functioning blebs (Intraocular pressure (PIO)&lt;21mmHg without therapy) and nonfunctioning blebs (PIO&lt;21mmHg with therapy or ≥21mmHg).Results Biomicroscopically, functioning blebs, in comparison to nonfunctioning blebs, showed a significant increase in the central (p=0,009) and maximal (p=0,017) bleb area and a decrease in central (p=0,021) and maximal (p=0,028) bleb vascularization. When comparing successful with failed blebs, in vivo confocal microscopic showed a significant increased number of epithelial microcysts (p=0,014), a liquid content of epithelial microcysts (p=0,008), a lower density of stromal connective tissue (p=0,039) and a decreased number (p=0,041) and diameter (p=0,045) of the vessels. All morphological findings were similar when comparing the usage of MMC with the usage of 5‐FU (p&gt;0,05).Conclusion This study suggests that both biomicroscopy and in vivo confocal microscopy findings can lead to a better understanding and management of filtering blebs.

Epiconjunctival Mitomycin-C Application for Early Failing Filtering Blebs

Purpose: To evaluate the effectiveness of epiconjunctival Mitomycin-C (MMC) application in early failing filtering blebs. Design: Interventional case series. Participants: Patients with failing blebs and raised intraocular pressure (IOP) in the early (two weeks to one month) postoperative period following glaucoma filtering surgery. Methods: A retrospective analysis of records of failed blebs was done for the period of April 2011-March 2012. Patients who were subjected to three applications of MMC (0.04%) applied over the conjunctiva directly over the bleb at baseline (visit1), one week (visit 2) and at one month (visit 3) were included. Bleb characteristics were graded in a blinded fashion by one independent ophthalmologist, while IOP during follow-up visits were analyzed. Main Outcome Measures: Intraocular pressure, need for additional measure, or medications and bleb characteristics as graded by Indiana classification. Results: Ten eyes of nine patients with failing blebs received topical MMC, including included eight males and one female with a mean age of 52 ± 18 years (trabeculectomy:combined surgery = 5:5). Complete success was seen in eight of 10 eyes with a final mean IOP of 14 ± 2.9 mm Hg at three months. Excluding the two eyes that required medications, IOP reduction of 9%–42% was seen at visit 2, 16–57% IOP reduction at visit 3, and 16–56% at three months’ follow-up. Of eight eyes, all eyes showed decrease in vascularity of the blebs, p < 0.001. While the height of the blebs did not show significant increase, all had increase in the avascular area of the bleb. One eye developed spontaneously resolving adenoviral conjunctivitis without any sequelae. Conclusion: Three applications of epiconjunctival MMC may be a safe alternative for salvaging failing blebs in the early postoperative period. This may help maximize anti-fibrotic effect of MMC while minimizing complications by limiting the area of contact.

Outcomes of same-site re-operation with minimal use of mitomycin in failed trabeculectomy

To evaluate efficacy and safety of same site re-operation in eyes with failed trabeculectomy. A retrospective, noncomparative, interventional case series. We reviewed the medical records of 35 eyes of 35 patients who underwent same-site re-operation for failed trabeculectomy. The surgery involved a fornix-based peritomy at the same site as the previous trabeculectomy with application of 0.2 mg/mL mitomycin for 1 min. Primary outcome measures were intraocular pressure (IOP) control and number of antiglaucoma medications at last follow-up. Success rates were defined according to criteria (A) IOP ≤ 21 mmHg or (B) IOP ≤ 18 mmHg, with or without antiglaucoma medication. The mean age of the patients was 43.3 ± 18.0 years and 62.9 % were male. The mean follow-up was 13.6 ± 12.0 months (range 6-49 months). At final follow-up, mean baseline IOP was reduced from 27.2 ± 8.0 to 16.6 ± 7.5 mmHg (p < 0001). The mean number of antiglaucoma medications was reduced from 2.8 ± 0.8 to 1.0 ± 1.3 (p < 0001). This study supports the efficacy and safety of same-site re-operation with minimal use of mitomycin C for management of failed filtering blebs following trabeculectomy.

In Vivo Confocal Microscopy and Ultrasound Biomicroscopy Study of Filtering Blebs after Trabeculectomy

To evaluate morphological features of filtering blebs after trabeculectomy with limbus-based versus fornix-based conjunctival flaps (LBCF and FBCF, respectively) using in vivo confocal microscopy (IVCM) and ultrasound biomicroscopy (UBM). Seventy-five eyes of 62 patients with glaucoma were recruited. Thirty-eight eyes of 31 patients received trabeculectomy with LBCF and 37 eyes of 34 patients received trabeculectomy with FBCF. Successful bleb was defined as postoperative intraocular pressure (IOP) ≤15 mm Hg and IOP reduction ≥20% without antiglaucoma medication. Microcyst number, density of subepithelial connective tissue, and vascularity of subepithelial tissue were evaluated by IVCM. Bleb reflectivity, the route under the scleral flap, bleb height, and height of fluid-filled space were examined by UBM. On the basis of IOP criteria, 79% (30 of 38 blebs) of the LBCF group and 70% (26 of 37 blebs) of the FBCF group were defined as successful blebs (P=0.28). Compared with the successful FBCF group, the successful LBCF group had a larger microcyst number (P<0.001), lower density of subepithelial connective tissue (P=0.046), greater avascularity of subepithelial tissue (P=0.024), and higher height of fluid-filled space (P=0.017). No morphological differences between LBCF and FBCF groups were found in failed blebs. Morphological features of successful blebs in IVCM and UBM were different between blebs with LBCF and FBCF. Type of conjunctival flaps should be considered when estimating the bleb function based on bleb morphology examined with these imaging devices.

Effects of trabeculectomy on posture-induced intraocular pressure changes over time

To determine whether trabeculectomy affects postural-induced changes in intraocular pressure (IOP), and whether it is maintained. Thirty-six eyes of 36 patients with open-angle glaucoma who were scheduled for their initial trabeculectomy with adjunctive mitomycin C were prospectively examined. The IOP was measured in the sitting and the lateral decubitus position with an ICare rebound tonometer before, and 1, 3, and 12 months after trabeculectomy. Twenty-nine eyes of 29 patients completed this study. The mean baseline IOP measured with the ICare tonometer was 17.4 ± 4.9 mmHg in the sitting position and 21.3 ± 5.6 mmHg in the lateral decubitus position (p < 0.001). This postural IOP difference, +3.9 mmHg, was reduced to +1.3 ± 1.7 mmHg at 1 month and to +0.8 ± 1.5 mmHg at 3 months after the trabeculectomy (p < 0.001 and p = 0.004 respectively). This decrease in the degree of posture-dependent IOP change was maintained at +1.7 ± 2.2 mmHg at 1 year postoperatively (p < 0.001). In three cases, the postural IOP changes returned to the baseline level, and all three had a failed bleb. Our results indicate that trabeculectomy not only reduces the IOP but also reduces the degree of posture-induced changes in the IOP. Our findings also speculate that measuring the postural IOP changes after trabeculectomy might provide a clue on the functioning of a filtering bleb.

Use of Ultrasound Biomicroscopy to Predict Long-Term Outcome of Sub-Tenon Needle Revision of Failed Trabeculectomy Blebs: A Pilot Study

To evaluate the role of ultrasound biomicroscopy (UBM) in predicting the long-term outcome of sub-Tenon needling revision of failed trabeculectomy blebs. Adult patients with a failed trabeculectomy bleb and unsatisfactory intraocular pressure (IOP) control were recruited. The aqueous flow under the partial thickness scleral flap was looked for and the blebs classified on UBM as scleral route patent (SRP) or scleral route occluded (SRO). All blebs underwent needling revision with injection of 5 mg/0.1 mL 5-fluorouracil. Survival of the revision procedure at the end of 2 years follow-up with regards to the baseline UBM characterization of the bleb was noted. Successful outcome was defined as IOP <22.0 mmHg and/or 30% reduction of baseline IOP with or without medication. A total of 13 eyes had SRP and 5 eyes had SRO blebs on UBM. Only SRP blebs survived the needling procedure by the end of 2 years. Of the 13 SRP blebs, 10 blebs survived (76.9%). Needling had failed in all 5 SRO blebs. The overall success rate was 55.6% at 2 years. There was no difference in age, IOP, and time from initial trabeculectomy between the failed and successful group. The outcome correlated significantly to the patency of the scleral route assessed by UBM (p=0.07). Ultrasound biomicroscopy characterization of failed blebs appears to help in predicting the outcome of needle revision. In SRO blebs, it may be better to plan a full bleb revision rather than needling alone. Ultrasound biomicroscopy may help in avoiding an unnecessary needling procedure in SRO blebs where it is likely to fail.

Needling: A Potential option for Trabeculectomy Bleb Failure

Trabeculectomy still remains the standard procedure of choice for a patient with uncontrolled glaucoma on maximum tolerated medical therapy and/or after laser. Although it has a high success rate of its own, a small number of patients continue to have a failing or a failed bleb despite a good bleb management. Needling had been a well-known modality of bleb management described in literature which has refined itself through years. However, in most of the situations, this modality of treatment is least considered. In this review, we will go through the evolution of needling procedure and various related options, their success rates, complications and emerging trends.

Mitomycin-C needle bleb revision in congenital glaucoma

Purpose and Settings:This study was designed to evaluate the efficacy and safety of mitomycin-C (MMC) augmented needling procedure in the management of failed bleb after trabeculectomy in congenital glaucoma. This study was carried out at Ain Shams University Hospital.Patients and Methods:A retrospective study was carried on 30 eyes of 25 patients with congenital glaucoma with bleb failure after trabeculectomy. The mean age of the subjects was 7.3 ± 3.4 years (range, 1–12 years). Under general anesthesia, needling procedure was performed with adjunctive use of a mixture of 0.1 mL of MMC (0.04 mg/mL) and 0.2 mL of lidocaine 1% injected subconjunctivally. Needling was performed with a 30-gauge needle to dissect the areas of subconjunctival fibrosis and re-establish aqueous outflow.Results:Follow-up ranged from 6 to 20 months (mean, 9.23 ± 5.25 months). One needling revision was performed in 22 eyes (73.3%) and eight eyes (26.7%) received two needle revisions. The mean intraocular pressure (IOP) decreased from 26.9 ± 2.85 mmHg (range, 21–34 mmHg) before surgery to 15.63 ± 3.15 mmHg (range, 10–24 mmHg) at last follow-up. Complications included significant subconjunctival hemorrhage in six eyes, intraoperative bleb leak in two eyes, choroidal detachment in one eye, and minimal hyphema in one eye.Conclusion:MMC needle bleb revision appears to be an effective method to revive failed filtration surgery after trabeculectomy in patients with congenital glaucoma. This technique is effective in reducing IOP with preservation of the remaining conjunctiva for further surgery.

High‐definition imaging of trabeculectomy blebs using spectral domain optical coherence tomography adapted for the anterior segment

The aim of this work was to image trabeculectomy blebs using spectral domain optical coherence tomography (SDOCT). In this prospective cross-sectional study, patients who had undergone trabeculectomy with at least 3 months of follow up were included. Blebs were imaged using an adapted SDOCT system (Cirrus HD-OCT, Carl Zeiss Meditec Inc., Dublin, CA, USA) and time domain anterior segment optical coherence tomography (ASOCT) (Visante OCT, Carl Zeiss Meditec Inc.). An observer masked to clinical data assessed the utility of SDOCT and ASOCT in visualizing structures in successful and failed blebs. Fifty-one eyes were imaged, of which 43 (84.3%) were successful. SDOCT showed wall thickening (93.0% vs. 67.4%, P = 0.006) and discrete hyporeflective spaces in the wall (88.4% vs. 14.0%, P < 0.0001) in a greater proportion of successful blebs than ASOCT. SDOCT showed the bleb cavity (23.3% vs. 48.8%, P = 0.02), scleral flap (34.9% vs. 90.7%, P < 0.0001), subflap space (20.9% vs. 72.1%, P < 0.0001) and ostium (9.3% vs. 88.4%, P < 0.0001) in fewer successful blebs than ASOCT. The internal ostium was not visualized in any failed bleb using SDOCT, whereas ASOCT showed the ostium in 87.5% of failed blebs (P = 0.001). SDOCT showed cystic spaces in the bleb wall in a greater proportion of successful blebs than failed blebs (88.4% vs. 37.5%, P = 0.005). SDOCT imaging was able to show fine superficial features in the bleb wall. However, SDOCT had limited clinical utility in that it did not provide useful information about deep features such as flap position, bleb cavity formation or patency of the subflap space and internal ostium.

Filtering Bleb Functionality: A Clinical, Anterior Segment Optical Coherence Tomography and In Vivo Confocal Microscopy Study

To provide a microscopic and macroscopic analysis by a clinical, in vivo confocal microscopy (IVCM) and anterior segment optical coherence tomography (AS-OCT) assessment of filtering blebs after glaucoma surgery. We retrospectively analyzed 60 eyes of 48 glaucomatous patients by slit-lamp, IVCM, and AS-OCT examinations. Patients were divided into 2 groups: successful blebs (group 1, 16 patients, 27 eyes) were defined as a one-third reduction in preoperative intraocular pressure without antiglaucoma medications and failed blebs (group 2, 32 patients, 33 eyes) as a less than one-third reduction in preoperative intraocular pressure without therapy. The examinations were performed from 1 to 96 months postoperatively. Diffuse or cystic clinical patterns were indicative for good functionality whereas flat or encapsulation was indicative for poor functionality. When comparing successful with failed blebs, the IVCM analysis showed a greater number (P=0.014), density (P=0.009), and total area of epithelial microcysts (P=0.017) and a lower density of connective tissue (P=0.006). The AS-OCT analysis showed a lower degree of bleb wall reflectivity (P<0.001). A significant correlation was found between the clinical and AS-OCT parameters, particularly for the cystic (100%) and diffuse (74%) patterns. All IVCM parameters did correlate well with the bleb functionality whereas, among the AS-OCT parameters, only the bleb wall reflectivity was significantly related to the filtering capability. Clinical and AS-OCT bleb classification showed a significant degree of concordance. As a consequence, simultaneous approach by clinical, microscopic, and tomographic assessment improves the clinician's ability in the postsurgery understanding and management of blebs.

Potential Role of Tissue Transglutaminase in Glaucoma Filtering Surgery

Scarring of the filtering bleb site is the main cause of failure in glaucoma filtration surgery. In the present study, the role of tissue transglutaminase (tTgase) in the accumulation of extracellular matrix (ECM) proteins in these scars was investigated. Transglutaminases are enzymes capable of cross-linking ECM proteins to proteolysis-resistant complexes. Expression of tTgase, its reaction product epsilon-(gamma-glutamyl)-lysine, and fibronectin and their colocalization were investigated immunohistochemically in failed blebs and in an in vitro trabeculectomy model. Failed blebs were analyzed by RT-PCR for the presence of tTgase mRNA. Human Tenon fibroblasts (HTFs) were treated with transforming growth factor-beta2 (TGF-beta2). The effect was studied with immunohistochemistry, Northern blot analysis, and Western blot analysis. tTgase activity was assayed by incorporation of biotinylated cadaverine into fibronectin. Expression of tTgase and epsilon-(gamma-glutamyl)-lysine was present in all failed blebs. Staining was most prominent at the rim of the Tenon cyst. In the in vitro trabeculectomy model, tTgase and epsilon-(gamma-glutamyl)-lysine were barely present at the incision side of the flap but were perspicuously increased by TGF-beta2 treatment. Enzyme and its reaction product were colocalized with fibronectin. Cultured HTFs contained a basal level of tTgase mRNA. After treatment with TGF-beta2, expression and activity of tTgase significantly increased. The findings demonstrated that tTgase is present and functionally active in failed blebs. Expression and activity of tTgase appeared to be stimulated by TGF-beta2, a growth factor known to be increased in primary open angle glaucoma. Intervention at this pathway might open a new approach to prevent scarring after glaucoma filtration surgery.

Repermeabilización mediante revisión con aguja de ampollas de filtración con fracaso tardío tras cirugía de glaucoma

To evaluate the results of bleb needling in eyes subjected to filtering surgery six months or more previously. A retrospective study of 23 eyes in 21 patients subjected to bleb needling performed by means of a 25G needle, 6 months to 23 years after failed filtering surgery (mean 67.3 months). The mean number of bleb needlings was 1.2 and the mean number of 5-fluorouracil subconjunctival injections was 3.9. The mean intraocular pressure (IOP) before needling was 26 mmHg and the mean anti-glaucoma medications was 1.3 per eye. The mean postoperative IOP was 16.3 mmHg and mean anti-glaucoma medications 0.7. A diffuse filtering bleb was evident in 12 eyes (54.5%). The results of needling were worse in eyes subjected to previous surgery for glaucoma or other failed bleb needling procedures (75% failure). Needle revision of the filtering bleb is a simple and safe technique that offers good results even years after a filtering surgery had been performed. It should be considered before other medical or surgical treatments in patients with a previously functioning bleb and a permeable sclerectomy site at gonioscopy.

Rescue of failed filtering blebs with ab interno trephination

We evaluated the effectiveness of ab interno automated trephination as a technique for rescuing failed mature filtering blebs. A retrospective chart review of 40 failed blebs of 38 patients who had a posttrephination follow-up period of at least 3 months was done. With success defined as intraocular pressure (IOP) <21 mm Hg and at least a 20% reduction from baseline on the same or fewer number of pretrephination medications, 30/40 eyes (75%) fit these criteria over the entire course of follow-up. Among all 40 eyes, there was a significant reduction of IOP from pretrephination to 3 months (P<.001). The percentage of patients requiring 2 or more medications declined from 90% pretrephination to 21% at 3 months (P<.0001), and was stable thereafter. Some patients were able to eliminate all medications. Patients who did not meet the criteria of success regained successful IOP control with other modalities of management. Complications were few. We believe that ab interno trephination is an excellent option for rescuing selected failed filtering blebs.

This Issue of Acta

This Issue of Acta

Anatomic and Histopathologic Findings Following A Failed Ahmed Glaucoma Valve Device

Ahmed glaucoma valve implant (AGV) is one of the more commonly used implants in difficult glaucomas. The histology of a functioning bleb following AGV implantation and its anatomic relationship to the optic nerve when placed in the superionasal quadrant has been described. We report the histology of a failed bleb and the anatomic relationship between the optic nerve and the AGV end-plate when placed 9 mm from the limbus in a patient with neovascular glaucoma.

Surgical revision of failed filtering bleb with mitomycin C

The revision of a failed filtering bleb using mitomycin C was performed in 40 eyes (28 eyes with primary open angle glaucoma and 12 eyes with secondary open angle glaucoma) in which the previous trabeculectomy using 5-fluorouracil had failed to control intraocular pressure (IOP). Presurgical IOP ranged from 21 approximately 36 mm Hg (average: 24.7 mmHg) with the maximum tolerable antiglaucoma medication. The follow-up period was at least 2 years (24 approximately 60, mean: 39.8 months). Mitomycin C (0.04%, 5 ml, 5 min) was applied under the subconjunctival space. After rinsing, the wall of the scarred bleb was incised in cases with a localized bleb, or the margin of the scleral flap was incised in cases without a filtering bleb. The conjunctival wound was closed with 10-0 Nylon sutures. IOP control under 21 mmHg was achieved in 53.4% without medication and in 60.2% with or without medication at 60 months. After repeating the same procedure, IOP control was obtained in 82.2% with or without medication at 60 months. The success rate in secondary open angle glaucoma was less than in primary open angle glaucoma. Complications such as flattening of the anterior chamber requiring reformation (8%), choroidal detachment (8%), hyphema (5%), and hypotonic maculopathy (5%) were less than after trabeculectomy but conjunctival wound separation (5%) occurred little more frequently.