Bleb Wall Research Articles

Changes in filtering bleb morphology after bleb-related infection.

To verify, by use of data collected by the Japan Glaucoma Society Survey of Bleb-related Infection (JGSSBI), that bleb morphology changes within 12 months of the development of bleb-related infection. JGSSBI data from 57 eyes of 57 patients with primary open-angle glaucoma and normal tension glaucoma who developed a bleb-related infection were analyzed. Morphological features of the blebs were graded by use of a predetermined grading system. Multiple logistic regression analysis was conducted to identify factors relating to bleb morphology which were associated with poor outcome. Bleb sizes, including both circumferential and tangential lengths, were significantly smaller for stage IIIa/IIIb infections than for stage I/II bleb infections (P = 0.009 and P = 0.026 for the circumferential and tangential lengths, respectively; Fisher's direct probability test). The bleb wall also became significantly thicker during stage IIIa/IIIb infections (P = 0.003). After infection, intraocular pressure (IOP) increased significantly for all cases but was no different in the three subgroups (i.e. stage I, stage II, and stage IIIa/IIIb bleb infections). Multiple logistic regression analysis revealed that a stage III infection was significantly associated with a poor outcome for the bleb. This study revealed that the filtering bleb became smaller, both tangentially and circumferentially, and thicker, after stage III infections than after stage I or II infections.

Effect of laser suture lysis on filtration openings: a prospective three-dimensional anterior segment optical coherence tomography study.

To investigate the effects of laser suture lysis (LSL) on filtration openings after trabeculectomy. Prospective study analyzing the changes in the location and width of filtration openings, fluid cavity height, total bleb height, bleb wall thickness, and bleb wall intensity before and after LSL using three-dimensional anterior segment optical coherence tomography (3D AS-OCT). Fourteen patients had clear scleral flap image analysis. As five patients underwent LSL twice and two patients underwent LSL thrice, 23 comparison studies were possible. After LSL the intraocular pressure (IOP) decreased (P = 0.0015) from 20.5 ± 5.3 to 14.9 ± 6.4 mm Hg, and the fluid cavity height increased significantly from 0.2 ± 0.2 mm to 0.3 ± 0.1 mm (P = 0.0094). Other bleb parameters were not significantly different when comparing before and after LSL. When the IOP reduction ratio was > 25% following LSL, the width of the filtration openings on the LSL side, the total bleb height, and the fluid cavity height increased (P = 0.0273, 0.0342, and 0.0024, respectively). In multiple regression analysis the changes in fluid cavity height, the wall thickness, the wall intensity, and the width of the filtration opening were positively associated with the IOP reduction rate (P = 0.0428, 0.0226, 0.0420, and 0.0356, respectively). 3D AS-OCT allowed a detailed examination of the internal morphology of filtration blebs and openings before and after LSL. The changes in the internal morphology were closely associated with the success of LSL to decrease IOP.

Effect of Two Novel Sustained-Release Drug Delivery Systems on Bleb Fibrosis: An In Vivo Glaucoma Drainage Device Study in a Rabbit Model.

To evaluate two drug delivery systems, a nonbiodegradable poly(2-hydroxyethyl methacrylate) (P[HEMA]) system with mitomycin C (MMC) and a biodegradable poly(lactic-co-glycolic acid) (PLGA) system with 5-fluorouracil (5-FU) with and without MMC for their ability to reduce fibrosis when attached to an Ahmed glaucoma valve (AGV) and implanted in a rabbit model. New Zealand albino rabbits (48) were divided into six equal groups, and AGVs, modified as described below, were implanted in the right eye of each rabbit. The groups included (1) PLGA alone; (2) P(HEMA) plus MMC (6.5 μg); (3) PLGA plus 5-FU (0.45 mg); (4) PLGA plus 5-FU (1.35 mg); (5) PLGA plus 5-FU and MMC (0.45 mg and 0.65 μg, respectively); (6) PLGA plus 5-FU and MMC (1.35 mg and 0.65 μg, respectively). The rabbits were followed for 3 months prior to euthanasia. The bleb wall thickness was significantly less in groups 2, 5, and 6 compared to the rest. At 3 months, the PLGA polymer had completely disappeared, while the P(HEMA) polymer remained intact. There were no statistical differences in the degree of clinically graded conjunctival injection, histologic inflammation, or histologic fibrosis among the six groups. We successfully created a sustained-release drug delivery system that decreased the postoperative fibrosis using both a nonbiodegradable P(HEMA) polymer and a biodegradable (PLGA) polymer. Both systems appear to work equally well with no side effects. These results are supportive of the antifibrotic effect of the slow-release drug delivery system following glaucoma drainage device implantation, thus paving the way for human pilot studies.

Filtering blebs using 3-dimensional anterior-segment optical coherence tomography: a prospective investigation.

Posttrabeculectomy changes in bleb parameters measured using 3-dimensional (3-D) anterior-segment optical coherence tomography (OCT) remain uncharacterized and might be related to postsurgical intraocular-pressure (IOP) control. To evaluate time-dependent posttrabeculectomy changes in filtering bleb parameters using 3-D anterior-segment OCT. This prospective observational study was conducted at Kumamoto University Hospital, Kumamoto, Japan. Patients with open-angle glaucoma who underwent uncombined fornix-based trabeculectomy at Kumamoto University Hospital between January 1, 2012, and October 31, 2012, were included. Twenty-nine eyes were enrolled, 23 of which were followed up for 1 year without additional glaucoma surgical procedures; 3 required additional glaucoma surgery. Imaging filtering blebs using 3-D anterior-segment OCT. The primary end points were changes in bleb parameters including the position and width of the filtration openings on the scleral flap, the total bleb height, fluid-filled cavity height, bleb wall thickness, and bleb wall intensity, which were measured using 3-D anterior-segment OCT. The secondary end points were postsurgical IOP measured 0.5, 3, 6, and 12 months after trabeculectomy, and the effects of aqueous cytokine levels on the bleb parameters. We observed increased total bleb height (0.82 to 1.25 mm; difference: 95% CI, 0.10 to 0.75; P = .01), bleb wall thickness (0.46 to 0.61 mm; difference: 95% CI, 0.02 to 0.28; P = .03), and distance from the top of the scleral flap to the filtration opening (1.69 to 2.16 mm; difference: 95% CI, 0.28 to 0.70; P < .001), as well as decreased width of the filtration opening (2.08 to 1.12 mm; difference: 95% CI, -1.75 to -0.49; P = .002) between 0.5 and 12 months posttrabeculectomy. The filtration openings tended to close from the fornix side of the scleral flap during the wound healing process. Moreover, the width of the filtration opening at 0.5 months posttrabeculectomy correlated with the IOP at 12 months (P = .02). The aqueous humor level of monocyte chemoattractant protein-1 was correlated with the width of the filtration opening at 3 and 6 months posttrabeculectomy. The width of the filtration opening at 0.5 months posttrabeculectomy correlated with the IOP at 12 months. The width of the filtration opening at the early stage may be a prognostic factor for long-term IOP control. Large-scale studies with longer follow-up periods are required.

Fiber-based polarization-sensitive OCT for birefringence imaging of the anterior eye segment.

We demonstrate a prototype system of polarization-sensitive optical coherence tomography (PS-OCT) designed for clinical studies of the anterior eye segment imaging. The system can measure Jones matrices of the sample with depth-multiplexing of two orthogonal incident polarizations and polarization-sensitive detection. An optical clock is generated using a quadrature modulator and a logical circuit to double the clock frequency. Systematic artifacts in measured Jones matrices are theoretically analyzed and numerically compensated using signals at the surface of the sample. Local retardation images of filtering blebs after trabeculectomy show improved visualization of subconjunctival tissue, sclera, and scar tissue of the bleb wall in the anterior eye segment.

Evaluation of filtering blebs exhibiting transconjunctival oozing using anterior segment optical coherence tomography.

To explore the features of filtering blebs exhibiting transconjunctival oozing via three-dimensional anterior segment optical coherence tomography (3D AS-OCT). In this cross-sectional study, 131 eyes of 131 patients exhibiting filtering blebs were examined. Of those, 20 eyes were excluded as flat-shaped, non-functioning bleb. Transconjunctival oozing was defined as transconjunctival aqueous egress evident on the bleb surface, in the absence of any point leak observable using a slit-lamp, as confirmed by application of digital pressure. Total bleb height, the height of the fluid-filled cavity, and bleb wall thickness and density were measured using 3D AS-OCT. Patient age, the etiology of glaucoma, postoperative follow-up period, number of glaucoma medication classes prescribed, intraocular pressure (IOP), grade of bleb vascularity, and bleb parameters were compared in eyes with and without bleb oozing. Sixty (54.0 %) of 111 eyes excluding non-functioning flat blebs exhibited oozing; mean IOP value (11.7 ± 4.5 vs. 14.8 ± 4.0 mmHg) and bleb vascularity grade (1.5 ± 0.7 vs. 2.4 ± 1.0) were lower than those of eyes without oozing. Total bleb height (1.1 ± 0.4 vs. 0.9 ± 0.4 mm), bleb wall thickness (0.7 ± 0.4 vs. 0.5 ± 0.3 mm), and bleb wall density (131.3 ± 45.7 vs. 180.9 ± 39.8 optical density units) differed significantly between the two groups (oozing vs. non-oozing). Transconjunctival oozing after trabeculectomy with MMC was associated with a low IOP, low-level bleb vascularity, an elevated total bleb height, a thicker bleb wall, and low bleb wall density.

Anterior Segment Optical Coherence Tomography Imaging of Filtering Blebs after Deep Sclerectomy with Esnoper-Clip Implant: One-year Follow-up

ABSTRACTPurpose: To describe the technique of deep sclerectomy with the new Esnoper-Clip® implant, the clinical outcome and the anatomic characteristics of filtering blebs, using anterior segment optical coherence tomography (AS-OCT).Methods: A prospective case-series study was conducted in five eyes (5 patients) with open angle glaucoma. The fornix-based deep sclerectomy with Esnoper-Clip® implant was done by the same surgeon. In one case, mitomycin C was used during surgery. All participants underwent a complete ophthalmic examination and AS-OCT (Visante®) preoperatively, then at each follow-up visit, at 1 day, 1 week, 1 month, 6 months and 1 year postoperatively. Scans were obtained through sagittal and transversal plans to the implant.Results: Intraocular pressure (IOP) was significantly reduced (p < 0.05) from a mean preoperative value of 23.4 ± 8.6 mm Hg (n = 3.8 glaucoma medications) to a postoperative value of 6.0 ± 2.5 (n = 0), 10.6 ± 5.4 (n = 0), 13 ± 1.6 (n = 0.4), 12.4 ± 2.1 (n = 0.2) and 14.4 ± 1.5 (n = 0.2) at 1 day, 1 week, 1 month, 6 months and 1 year respectively. AS-OCT allowed the visualization of the two plates of the implant (scleral and suprasciliary), the trabeculodescemetic membrane and the hyporeflective spaces in the bleb wall thickness and in suprascleral and suprachoroidal localizations. An immediate postoperative hypotony and an anteriorization of the implant associated to trabeculodescemetic membrane rupture, were detected, although without significant clinical repercussions.Conclusion: Our first five deep sclerectomy with Esnoper-Clip implantation analysis suggest an effective and well-tolerated method to reduce IOP. AS-OCT is a noninvasive imaging technique that allows the anatomic analysis of the drainage mechanisms after glaucoma surgery.How to cite this article: Vieira L, Noronha M, Lemos V, Reina M, Gomes T. Anterior Segment Optical Coherence Tomography Imaging of Filtering Blebs after Deep Sclerectomy with Esnoper-Clip Implant: One-year Follow-up. J Curr Glaucoma Pract 2014;8(3):91-95.

Serial changes in the bleb wall after glaucoma drainage implant surgery: characteristics during the hypertensive phase.

To investigate serial changes in the bleb wall using anterior segment optical coherence tomography (AS-OCT) in patients who had undergone Ahmed glaucoma valve (AGV) implantation. A total of 52 patients who had undergone AGV implantation were enrolled. Reflectivity and mean thickness of the bleb wall were examined using AS-OCT at 1 day, 1 week, 1 month, 3 months and 6 months postoperatively. Intra-ocular pressure (IOP) and the number of glaucoma medications were evaluated. The hypertensive phase was defined as IOP >21 mmHg during the first 3 months after surgery. Patients were divided into two groups: hypertensive and non-hypertensive groups. Following AGV implantation, IOP decreased at each time-point during postoperative follow-up (p value < 0.001, all) with a peak in the first month. Mean bleb wall thickness showed a U-shaped curve postoperatively, being thinnest 1 month after the operation. Reflectivity showed an inverted U-shaped curve postoperatively, being brightest 1 month after the operation. A hypertensive phase was observed in 44 patients (84.6%). The bleb wall was significantly more reflective (130.67 ± 27.00 versus 106.57 ± 10.35; p = 0.044) in the hypertensive group than in non-hypertensive group 1 month postoperatively. Hypertensive phase peaked at 1 month after aqueous shunt surgery. At that time, the bleb wall had the highest reflectivity. The unique IOP pattern after tube surgery is related to fibrosis of the bleb wall qualitatively. Specific modulation of wound healing may be the target for attempts to decrease the development of hypertensive phase.

Serial changes in the bleb wall after glaucoma drainage implant surgery: Characteristics during the hypertensive phase

AbstractPurpose To investigate serial changes in the bleb wall using anterior segment‐optical coherence tomography (AS‐OCT) in patients who had undergone Ahmed glaucoma valve (AGV) implantationMethods A total of 52 patients who had undergone AGV implantation were enrolled. Reflectivity and mean thickness of the bleb wall were examined using AS‐OCT at 1 day, 1 week, 1 month, 3 months, and 6 months postoperatively. Intraocular pressure (IOP) and the number of glaucoma medications was evaluated. The hypertensive phase was defined as IOP &gt; 21 mmHg during the first 3 months after surgery. Patients were divided into two groups: hypertensive and non‐hypertensive groups.Results Following AGV implantation, IOP decreased at each time point during postoperative follow‐up (P value &lt; 0.001, all) with a peak in the first month. Mean bleb wall thickness showed a U‐shaped curve postoperatively, being thinnest 1 month after the operation. Reflectivity showed an inverted U‐shaped curve postoperatively, being brightest 1 month after the operation. A hypertensive phase was observed in 44 patients (84.6%). The bleb wall was significantly more reflective (130.67 ± 27.00 vs. 106.57 ± 10.35; P = 0.044) in the hypertensive group than in non‐hypertensive group 1 month postoperatively.Conclusion Hypertensive phase peaked at 1 month after aqueous shunt surgery. At that time, the bleb wall had the highest reflectivity. The unique IOP pattern after tube surgery is related to fibrosis of the bleb wall qualitatively. Specific modulation of wound healing may be the target for attempts to decrease the development of hypertensive phase.

Qualitative and quantitative analysis of filtering blebs with optical coherence tomography

ObjectiveTo provide a qualitative and quantitative analysis of filtering blebs with optical coherence tomography (OCT) in patients after primary trabeculectomy. DesignEvaluation of diagnostic technology. ParticipantsWe retrospectively studied 20 eyes of 20 patients who had a fornix-based flap in primary trabeculectomy: 14 with mitomycin C (MMC) and 6 without MMC. MethodsFiltering blebs were examined using 2 types of OCTs working at a wavelength of 840 and 1310 nm. In this study, we analyzed both the OCT morphologic pattern and the internal structures of blebs, including bleb wall thickness, scleral flap thickness, and the route under the scleral flap, and quantified the reflectivity of the intrableb area. ResultsBlebs were classified according to the Hirooka scheme in 3 OCT morphologic patterns: cystoid, diffuse, and layer type. The MMC was associated with the surgical success (100%). A significant association was found between good functionality and cystoid type with both devices: 840-nm OCT (p = 0.02) and 1310-nm OCT (p = 0.04). A significant difference in morphologic patterns was found using the 2 OCTs. There were no significant differences between successful and unsuccessful filtering surgery for intrableb structures. The reflectivity of filtering blebs correlated very well to the postoperative intraocular pressure (IOP; R2 = 0.90; p < 0.001) and to the reduction of IOP (R2 = 0.58; p = 0.001). Our method to quantify the reflectivity showed a significant degree of intergrader consensus (intraclass correlation coefficient = 0.99; p < 0.001). ConclusionsAlthough 840-nm OCT was not developed to assess the anterior segment, it may be considered a useful tool to evaluate the functionality of blebs in the postoperative period.

Morphology of functioning trabeculectomy blebs using anterior segment optical coherence tomography.

Purpose:To image trabeculectomy blebs using anterior segment optical coherence tomography (AS-OCT), and to correlate the bleb morphologic features at one month postoperatively with bleb function at six months.Materials and Methods:This prospective, observational study included 56 eyes undergoing trabeculectomy with MMC, followed up for minimum of six months. Postoperatively, bleb imaging was done using AS-OCT at one and six month. Bleb morphology was assessed for bleb wall reflectivity, bleb pattern in multiform reflectivity, visibility of drainage route and presence of hyper-reflectivity area. Bleb function was considered successful if IOP was <18 mmHg without medication at six month. Bleb morphology one month postoperatively was correlated with bleb function at six months.Results:At six months successful bleb function was noted in 44 (81.5%) eyes. Morphology of bleb at one month showed uniform bleb wall reflectivity in 6 eyes (11%) and multiform wall reflectivity in 48 eyes (89%). In eyes with multiform wall reflectivity, microcysts with multiple layers was seen in 26 eyes (48%), microcysts with subconjunctival separation in 12 eyes (22%) and only microcyst in 10 eyes (19%). When bleb features at one month were correlated with the bleb function at six months, logistic regression analysis revealed that blebs with multiform reflectivity with multiple internal layers with microcysts were associated with higher chances of success (P < 0.001).Conclusion:AS-OCT demonstrated early bleb morphological features that may be used to predict the functioning of a bleb. Multiform bleb wall reflectivity with a pattern of multiple internal layers and microcysts was associated with increased chances of success of a bleb.

Filtration Bleb Revision Guided by 3-Dimensional Anterior Segment Optical Coherence Tomography

To elucidate the usefulness of 3-dimensional anterior segment optical coherence tomography (3D AS-OCT) for bleb revision after trabeculectomy. Case series. Two patients who underwent trabeculectomy and subsequent bleb revision. Three-dimensional AS-OCT and intraoperative observation. AS-OCT and intraoperative observation were analyzed to identify the filtration openings on the scleral flap margin and leaking points. In 1 case with a leaking bleb, 3D AS-OCT examinations suggested the presence of numerous internal ostia (filtration openings). With 3D AS-OCT guidance, we carefully removed the leaking bleb with peripheral scar tissue. Histopathologic findings showed the presence of a thin bleb wall in the limbal conjunctiva corresponding to the point of aqueous leakage. In another case of an overhanging bleb, 3D AS-OCT examination revealed a thin bleb wall and multiloculated cystic structures. Histopathologic findings showed the presence of a thin region in the conjunctival epithelium in which connective tissue did not support the conjunctival epithelium, which seemed to correspond to the point at which oozing occurred. Three-dimensional AS-OCT enables evaluation of the internal morphology of filtration blebs and is useful for preoperative guidance for bleb revision.

Bleb Analysis by Using Anterior Segment Optical Coherence Tomography in Two Different Methods of Trabeculectomy

To investigate the correlation between bleb morphology and IOP control via the modified Indiana Bleb Appearance Grading Scale (IBAGS) and anterior-segment optical coherence tomography (AS-OCT) in two different trabeculectomy (TLE) groups. This study involved 94 eyes with primary open angle glaucoma that underwent two different TLE methods: limbal-based TLE (group I, 62 eyes) and fornix-based TLE (group II, 32). IOP control was defined as successful with an IOP ≤ 20 mm Hg and ≥20% reduction of preoperative IOP. IBAGS and various parameters of the bleb height, extent, wall thickness, ciliochoroidal detachment (CCD), and lake under the scleral flap (LUSF) were obtained by slit-lamp and AS-OCT, respectively. Correlation between IOP control and IBAGS/AS-OCT parameters were assessed by SAS. Both groups had the same success rate. As to correlation between IOP control and IBAGS, extent and Seidel were the best-paired parameters in group I (Cp = 3.0402, R = 0.6401), yet no parameter was significant in group II (maximum R = 0.1599). As to correlation between IOP control and AS-OCT, the combinations of height, extent, and the minimum value of bleb wall thickness were significant (Cp = 0.2037, 0.2314, R = 0.4336, 0.4330) in group I. In group II, no parameter was significant, except CCD and/or LUSF (P = 0.032). As to coincidence of IBAGS and AS-OCT parameters, height and extent in group I (P = 0.000, P = 0.000) and height in group II were statistically significant (P = 0.020). IOP control in limbal-based TLE seemed to be more dependent on the large size and thinned-wall bleb than that in fornix-based TLE.

Immunohistochemical analysis of extracellular matrix bleb capsules of functioning and non‐functioning glaucoma drainage implants

To detect by immunohistochemical means the changes in bleb capsules at the cellular level between functioning and non-functioning glaucoma drainage implants (GDIs). Three samples each of functioning (1 Baerveldt and 2 Molteno implants) and non-functioning filtration blebs (1 Molteno and 2 Ahmed implants) were studied. A non-functioning bleb was defined as an intra-ocular pressure (IOP) >21mmHg or a <20% reduction in IOP from baseline on three consecutive follow-up visits with maximal tolerated medication. The capsules were obtained between 6 and 108months after GDI insertion for medical reasons only. Primary antibodies were used to stain fibronectin, tenascin, laminin, collagen IV and smooth muscle actin (SMA). The samples were graded on the basis of the intensity and quantity of immunohistochemical staining into four categories as follows: no staining or a mild, moderate or marked staining. The non-functioning blebs expressed more fibronectin, tenascin and SMA through the whole capsule wall than the functioning blebs. In the functioning blebs, tenascin was found mainly in the inner layer of the capsule. More type IV collagen and laminin were also found in the non-functioning bleb capsules than in the functioning blebs. No difference was found between the bleb capsules irrespective of whether they had been perfused with aqueous humour immediately after surgery (Ahmed) or after a delay (Molteno, Baerveldt). Accumulation of extracellular matrix components and activated fibroblasts in the bleb capsules of non-functioning GDI indicates the presence of an active wound healing process, suggesting a possible reduction in filtration through the bleb wall.

Visualization of Blebs Using Anterior-Segment Optical Coherence Tomography after Glaucoma Drainage Implant Surgery

The current study investigated the internal structure of blebs using anterior-segment optical coherence tomography (AS-OCT) in patients who had undergone Ahmed glaucoma valve (AGV) (New World Medical Inc, Rancho Cucamonga, CA) implantation and compared the differences between successful and failed surgeries. Cross-sectional, observational study. A total of 76 patients who had undergone AGV implantation. The blebs after AGV implantation were examined using AS-OCT. The relationship between intraocular pressure (IOP) or the number of glaucoma medications and intrableb parameters was evaluated. Success was defined as IOP ≤ 21 mmHg with a maximum of 2 glaucoma medications, and the remaining cases were assigned to the "failed surgery group." Logistic regression was used to determine the predictive value of various bleb parameters measured by AS-OCT for bleb success. The bleb wall thickness (minimum and maximum) and the reflectivity of the bleb wall (mean, modal value, minimum, and maximum). Blebs from 46 successful (60.5%) and 30 failed (39.5%) AGV implantation surgeries were analyzed. The AS-OCT imaging of the intrableb configuration revealed a relatively regular surface and a homogeneous and hyperreflective bleb wall. The maximum and minimum bleb wall thicknesses were significantly different between the 2 groups (P<0.001, P<0.005). No significant differences were observed between the 2 groups in mean, modal, maximum, or minimum reflectivity of the bleb wall. The maximum and minimum bleb wall thicknesses were significantly correlated with the postoperative maximum IOP (r = 0.402, P<0.001; r = 0.280, P = 0.014). The maximum and minimum bleb wall thicknesses showed a significant correlation with the number of postoperative glaucoma eye drops (r = 0.452, P<0.001; r = 0.327, P = 0.004). Maximum bleb wall thickness was significantly associated with the success of AGV surgery by multivariate analysis (P<0.001). Anterior-segment OCT can be used for bleb imaging after glaucoma valve implantation. The AS-OCT results revealed that the maximum bleb wall was significantly thinner in successful AGV implant surgeries compared with unsuccessful AGV implant surgeries. This technique may facilitate the investigation of surgical outcomes and pathogenesis in patients receiving glaucoma valve implants. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Precise Identification of Filtration Openings on the Scleral Flap by Three-Dimensional Anterior Segment Optical Coherence Tomography

To elucidate the potential of three-dimensional anterior segment optical coherence tomography (3D AS-OCT) for identifying filtration openings where aqueous humor flows from the sclera into the subconjunctival space. We used 3D AS-OCT and custom software to identify filtration openings, which were defined by pits and/or troughs in fluid-filled cavities in both horizontal and vertical rasters and corresponding C-scan images of scleral flap margin in the blebs. We measured bleb parameters, and at least three different reviewers surveyed the complete 3D images of the internal structure of the filtration blebs and associated findings. We identified filtration openings in 118 (95%) of 124 eyes. Among these 118 eyes, we found only a single filtration opening in 90 eyes (76%) and two or more filtration openings in the remaining 28 eyes (24%). Filtration openings were located in the middle third of the scleral flap margins in 57 eyes (63%) of the 90 eyes. The pattern of incision and sutures used for closure of the conjunctival flap affected the location of the openings, but additional laser suture lysis did not. In 6 (5%) of the 124 eyes, filtration openings could not be identified because of high reflectivity and/or elevated bleb wall (2 eyes), and no fluid-filled cavities because a sponge-like structure masked the filtration openings just above the scleral flap (4 eyes). 3D AS-OCT allows, in most cases, detailed evaluation of internal morphology of filtration blebs and precise identification of filtration openings on the scleral flap margins after trabeculectomy.

Filtering Bleb Structure Associated with Long-Term Intraocular Pressure Control after Amniotic Membrane-Assisted Trabeculectomy

Purpose/Aim: To determine whether amniotic membrane transplantation (AMT) at trabeculectomy affects intrableb structures and which intrableb parameters are significantly correlated with the long-term intraocular pressure (IOP) control.Materials and Methods: Enrolled were 64 eyes of 56 glaucoma patients who underwent trabeculectomy without (36 eyes) or with (28 eyes) AMT. Bleb structure was evaluated by ultrasound biomicroscopy (UBM) at least one year after surgery. IOP control was defined as good when the eyes had a more than 30% decrease in the preoperative IOP and an IOP value <18 mmHg if the preoperative IOP was higher than 21 mmHg. Logistic regression analyses were conducted to identify factors significantly associated with IOP control.Results: Intervals between surgery and the timing of the UBM examinations (median; 2.5 years) and the overall frequency of good IOP control (28/36 in the eyes without AMT and 17/28 in those with AMT; chi-square test, P = 0.2276) were similar in the two groups. The eyes with AMT had a significantly lower number of type H (high reflective) or L (low reflective) blebs and a higher number of type E (encapsulated) blebs compared to those without AMT (P < 0.0001). Among independent variables, which included age, sex, glaucoma type, lens status, the number of ocular hypotensives, and previous intraocular surgeries, only type F (flattened) bleb in eyes without AMT (P = 0.0008, odds ratio [OR] = 0.0256) and no or limited intrableb fluid-filled space in eyes with AMT were significantly associated with poor IOP control (P = 0.0026, OR = 0.0111, and 0.0071, 0.0167, respectively).Conclusions: Intrableb structures after trabeculectomy alone versus AMT-assisted trabeculectomy were distinct. The bleb wall reflectivity in the former and the extent of the subconjunctival fluid-filled space in the latter were factors associated with long-term IOP control.

Imaging of trabeculectomy blebs with Visante anterior segment optical coherence tomography after digital ocular compression

We investigated changes in intrableb morphology of functioning trabeculectomy blebs with anterior segment optical coherence tomography (AS-OCT) after digital ocular compression. Sixty-eight patients who underwent fornix-based trabeculectomy were recruited from Seoul St. Mary's Hospital. Intraocular pressure (IOP) and AS-OCT images were taken before and after ocular compression. Bleb height and wall thickness and height and length of the internal cavity were measured by AS-OCT. The hyporeflective areas and number of microcysts were checked on both vertical and horizontal images. AS-OCT parameters for IOP change, bleb morphology, and interval between surgery and examination were compared. Ocular compression yielded significant changes for all AS-OCT parameters other than maximum bleb wall thickness in the 6- to 12-month period after surgery. Correlation between IOP change and AS-OCT parameters was greatest for the horizontal and vertical length of the internal cavity (Spearman rank correlation coefficient ρ = 0.717, P < 0.0001, and ρ = 0.866, P < 0.0001, respectively). Response to ocular compression in cystic blebs was mainly enlargement of the internal cavity and increase in bleb height. However, in diffuse filtering blebs, increases in the size of the hyporeflective areas and the number of microcysts were the main findings. From 12 months postoperatively, changes in AS-OCT intrableb parameters were significantly reduced, showing no difference after ocular compression. Digital ocular compression may be useful in maintaining bleb morphology when it is used for 6 months postoperatively. Response to ocular compression as assessed by bleb morphology was different.

The Assessment of the Filtering Bleb Function With Anterior Segment Optical Coherence Tomography

To assess the usefulness of anterior segment optical coherence tomography (AS-OCT) in evaluating postoperative filtering bleb function. Forty-eight eyes of 39 patients who had earlier undergone trabeculectomy were enrolled. Blebs were imaged with a commercially available AS-OCT system. The correlation between intraocular pressure (IOP) and 4 quantitative parameters, bleb height, bleb wall thickness, and the height and extent of internal cavity, and 2 qualitative parameters, bleb wall reflectivity, and the presence or absence of posterior episcleral fluid, were analyzed. Of the 39 participants, 25 (64.1%) were males (mean age, 65.3±10.0 y). The height and extent of the internal cavity and the bleb height were not correlated with the IOP. The bleb wall thickness was negatively (P=0.004) correlated with the IOP. The mean IOP in eyes with a low-reflectivity bleb wall was significantly (P=0.001) lower than in eyes with a high-reflectivity wall. The IOP levels were significantly (P=0.008) lower in eyes with posterior episcleral fluid than in eyes without it. AS-OCT is a useful tool to evaluate filtering bleb function. The height and extent of the total bleb and the internal cavity were not correlated with IOP control. A low-reflectivity wall and the presence of episcleral fluid were associated with lower IOP.

What Is New After 40 Years of Glaucoma Implants

Forty years ago, Molteno introduced the prototype of the present day long tube implant. Since then, modifications in size and shape and introduction of valve system have taken place. Aqueous has been shown to contain proinflammatory substances that have been shown to influence the thickness of the bleb wall, and the hypertensive phase has been seen with the implants. The effect of the aqueous may be modified by the use of systemic antiinflammatory medication or by surgical modification, namely supra-Tenon insertion of the implant. Recent studies have shown that tube implantation is as efficacious as trabeculectomy in patients who were either pseudophakic or earlier had failed filters. Newer nontube implants, such as the Express shunt, have been introduced along with others, such as the gold micro shunt implant and the iStent, presently in clinical trials.