Comparison of Two Clinical Bleb Grading Systems

Bleb vessel density as a predictive factor for surgical revisions after Preserflo Microshunt implantation

PURPOSE

Bleb failure is a common complication after glaucoma filtration surgery. Different bleb classification schemes incorporating filtration bleb vascularization have been proposed, but the reported correlation with intraocular pressure (IOP) has been variable, possibly because of subjective vascularization grading. The purpose of the present study was to evaluate bleb vascularization after Preserflo Microshunt (PM) implantation using anterior segment OCT-angiography (AS-OCTA) as a biomarker for bleb failure.

METHODS

Twenty-three eyes of twenty-three patients underwent PM implantation. Up to 12 months after surgery PM scleral passage-centred AS-OCTA measurements (PLEX Elite 9000) for bleb-vessel density (BVD) determination were performed and IOP as well as necessity for surgical revisions (needling and open revision) were documented. After multi-step image analysis (region of interest definition, artefact removal, binarization, BVD calculation), the predictive value of early postoperative BVD for surgical revisions was assessed using logistic regression modelling.

RESULTS

Baseline IOP (23.57 ± 7.75 mmHg) decreased significantly to 8.30 ± 2.12, 9.17 ± 2.33 and 11.70 ± 4.40 mmHg after 1, 2 and 4 week(s), and 13.48 ± 5.83, 11.87 ± 4.49, 12.30 ± 6.65, 11.87 ± 3.11 and 13.05 ± 4.12 mmHg after 2, 3, 6, 9 and 12 month(s), respectively (p < 0.001). Nine patients (39%) needed surgical revisions after a median time of 2 months. Bleb vessel densities at 2 and 4 weeks were significantly associated with future surgical revisions upon logistic regression analysis (2 W/4 W likelihood-ratio test p-value: 0.0244/0.0098; 2 W/4 W area under the receiver operating characteristics curve: 0.796/0.909).

CONCLUSION

Filtration bleb vessel density can be determined using AS-OCTA in the early postoperative period and is predictive for bleb failure after PM implantation.

A deep learning approach to investigate the filtration bleb functionality after glaucoma surgery: a preliminary study

PURPOSE

To distinguish functioning from failed filtration blebs (FBs) implementing a deep learning (DL) model on slit-lamp images.

METHODS

Retrospective, cross-sectional, multicenter study for development and validation of an artificial intelligence classification algorithm. The dataset consisted of 119 post-trabeculectomy FB images of whom we were aware of the surgical outcome. The ground truth labels were annotated and images splitted into three outcome classes: complete (C) or qualified success (Q), and failure (F). Images were prepared implementing various data cleaning and data transformations techniques. A set of DL models were trained using different ResNet architectures as the backbone. Transfer and ensemble learning were then applied to obtain a final combined model. Accuracy, sensitivity, specificity, area under the ROC curve, and area under the precision-recall curve were calculated to evaluate the final model. Kappa coefficient and P value on the accuracy measure were used to prove the statistical significance level.

RESULTS

The DL approach reached good results in unraveling FB functionality. Overall, the model accuracy reached a score of 74%, with a sensitivity of 74% and a specificity of 87%. The area under the ROC curve was 0.8, whereas the area under the precision-recall curve was 0.74. The P value was equal to 0.00307, and the Kappa coefficient was 0.58.

CONCLUSIONS

All considered metrics supported that the final DL model was able to discriminate functioning from failed FBs, with good accuracy. This approach could support clinicians in the patients' management after glaucoma surgery in absence of adjunctive clinical data.

The novel role of lymphatic vessels in the pathogenesis of ocular diseases

Historically, the eye has been considered as an organ free of lymphatic vessels. In recent years, however, it became evident, that lymphatic vessels or lymphatic-like vessels contribute to several ocular pathologies at various peri- and intraocular locations. The aim of this review is to outline the pathogenetic role of ocular lymphatics, the respective molecular mechanisms and to discuss current and future therapeutic options based thereon. We will give an overview on the vascular anatomy of the healthy ocular surface and the molecular mechanisms contributing to corneal (lymph)angiogenic privilege. In addition, we present (i) current insights into the cellular and molecular mechanisms occurring during pathological neovascularization of the cornea triggered e.g. by inflammation or trauma, (ii) the role of lymphatic vessels in different ocular surface pathologies such as dry eye disease, corneal graft rejection, ocular graft versus host disease, allergy, and pterygium, (iii) the involvement of lymphatic vessels in ocular tumors and metastasis, and (iv) the novel role of the lymphatic-like structure of Schlemm's canal in glaucoma. Identification of the underlying molecular mechanisms and of novel modulators of lymphangiogenesis will contribute to the development of new therapeutic targets for the treatment of ocular diseases associated with pathological lymphangiogenesis in the future. The preclinical data presented here outline novel therapeutic concepts for promoting transplant survival, inhibiting metastasis of ocular tumors, reducing inflammation of the ocular surface, and treating glaucoma. Initial data from clinical trials suggest first success of novel treatment strategies to promote transplant survival based on pretransplant corneal lymphangioregression.

Multi-Quantitative Assessment of AS-OCTA Complemented AS-OCT for Monitoring Filtering Bleb Function After Trabeculectomy

Purpose

The purpose of this study was to explore a quantitative grading system of the filtering bleb combined anterior segment optical coherence tomography angiography (AS-OCTA) vascular features and optical coherence tomography (OCT) morphological features.

Methods

One hundred three eyes of 103 patients diagnosed with primary open-angle glaucoma and undergone trabeculectomy over 6 months were divided into success and failure groups according to postoperative intraocular pressure (IOP) level. Vessel density (VD) and vessel diameter index (VDI) were examined by AS-OCTA. Bleb's morphology, including bleb height (BH), and microcyst-structure (MCS) were detected by AS-OCT. Multi-vascular model score (MVMS) was calculated by comprehensive factor analysis, and the comprehensive grading system (MVMS-MCS-BH) was analyzed by linear regression. The efficiency our method was verified by receiver operating characteristic (ROC) analysis.

Results

The VD and VDI were higher in the failure group and closely related to post-trabeculectomy IOP (all P = 0.000). The MVMS was mostly consisted of VD in all regions, and VDIs of nasal, central, and temporal positions in sequence. MVMS ≥0, BH <1.33, and non-MCS were significantly associated with IOP increasing (coefficient = -3.23, -3.69, and 8.10, all P = 0.000). MVMS-BH-MCS got a higher area under curve (AUC), sensitivity, and specificity (0.92, 100%, and 80.30%) than the slit-lamp method (0.62, 72.20%, and 46.43%, respectively).

Conclusions

The quantitative vascular characteristics detected by AS-OCTA were significant for the bleb monitor. The MVMS-BH-MCS grading system had achieved outstanding accuracy in reflecting the surgical results.

Translational Relevance

The multi-vascular biomarker and comprehensive evaluation combined vascular and morphological parameters yield useful information on surgical outcomes, and help ophthalmologists to monitor patients effectively.

Clinical value of anterior segment optical coherence tomography‑assisted Wuerzburg bleb classification system for bleb assessment following trabeculectomy

The Wuerzburg bleb classification system (WBCS) is an established tool for evaluating filtering blebs, while anterior segment optical coherence tomography (ASOCT) provides detailed information on inner bleb structure. The present study aimed to investigate the clinical value of ASOCT-assisted WBCS following trabeculectomy (TRAB). The present prospective, observational study included eyes that underwent TRAB. Bleb assessments using the WBCS were based on the image acquired by ASOCT. The WBCS scores were assessed at postoperative week 2 and postoperative month (POM) 1, 2, 3, 6 and 12. The surgical outcomes at 1 year were determined as success or failure. Spearman's analysis explored the correlation of WBCS scores with intraocular pressure (IOP) and surgical outcome. A total of 32 eyes from 32 patients were included in the present study. The WBCS total score significantly correlated with IOP at POM 1, 2, 3, 6 and 12 (P<0.05). For single parameters, microcysts demonstrated a good correlation with IOP at POM 1, 2, 3, 6 and 12 (P<0.05). The WBCS total score correlated well with surgical outcome at POM 2, 3, 6 and 12 (P≤0.005). Microcysts, vascularity and encapsulation significantly correlated with surgical outcomes (P<0.05). The results of the present study suggest that ASOCT-assisted WBCS is a simple and effective measurement system for blebs after TRAB in clinical practice, which correlates well with IOP and surgical outcomes. Blebs with a higher WBCS total score and microcysts score in the early postoperative period, such as at POM 2 and 3, are less likely to have surgical failure in the long term.

Rotational extraction of incarcerated iris (REII): a slit lamp technique to reduce incarcerated iris after nonpenetrating deep sclerectomy for glaucoma

PURPOSE

Iris incarceration is a complication of glaucoma filtering surgery that often requires surgery. We describe a technique for reduction of incarcerated iris at the slit lamp, dubbed rotational extraction of incarcerated iris (REII). A retrospective analysis of visual function and intraocular pressure (IOP) was done in patients treated with REII after nonpenetrating deep sclerectomy.

METHODS

We retrospectively evaluated a cohort of patients who received REII for iris incarceration after nonpenetrating deep sclerectomy for glaucoma. IOP (applanation) and visual acuity (VA) were measured day-of, and 1, 3, 6, and 12 months post-REII. Adverse events were recorded. Kaplan-Meier survival analysis was done with definitions of IOP control at 15, 18, and 21 mmHg.

RESULTS

Forty-one eyes of 41 patients were treated with REII. Median time to iris incarceration from glaucoma surgery was 50 days (range 1-1906). Mean pre-REII IOP ± SD was 33.7 ± 14.1 mmHg, which reduced to 11.5 ± 6.1 mmHg day-of. LogMAR VA was 0.72 ± 0.8 log units at baseline and was unchanged at 12 months (P = 0.53). Survival analysis demonstrated varying efficacy depending on the definition of success. 79.0 to 92.2% of eyes achieved IOP control immediately after REII, 39.5 to 71.1% at 1 month, 26.3 to 52.6% at 3 months, 21.1 to 44.3% at 6 months, and 10.5 to 38.0% at 12 months. Nearly half (47.4%) of eyes required a tube shunt by 12 months.

CONCLUSION

REII may be a safe, minimally invasive slit lamp procedure that can reduce incarcerated iris and delay more invasive intervention for 3-6 months in most eyes.

Characteristic Assessment of Angiographies at Different Depths with AS-OCTA: Implication for Functions of Post-Trabeculectomy Filtering Bleb

This study aimed to analyze the quantitative vascular biomarkers of filtering bleb function at different depths using anterior segment optical coherence tomography angiography (AS-OCTA). This cross-sectional study is registered on Clinicaltrails.gov (NCT 04515017). Forty-six eyes with primary open-angle glaucoma that had undergone trabeculectomy with mitomycin-C for more than six months were included. Vessel density (VD) and vessel diameter index (VDI) in the superficial layer (SL), Tenon’s layer (TL), and deep layer (DL) of the bleb were obtained. The VD and VDI were higher in the failure group (both p = 0.000). Significant correlations were found between the SL, TL, DL’s VDI, and IOP in the success group (p = 0.013, 0.016, 0.031, respectively). The VD of the TL and DL were related to IOP in the failure group (p = 0.012, 0.009). Tenon’s VD (TVD) and Tenon’s VDI (TVDI) correlated with IOP adjusting for TVD, TVDI, and the Indiana Bleb Appearance Grading Scale (IBAGS) (p = 0.009, 0.043) or Kenfeld grading system (KGS) (p = 0.011, 0.016). The area under curve (AUC) of the TVD, TVDI, IBAGS, and KGS to predict surgery failure were 0.960, 0.925, 0.770, and 0.850. AS-OCTA realized the quantitative evaluation of vessels, especially the invisible vascularity beneath the conjunctiva. TVD and TVDI as detected by AS-OCTA better reflected bleb function than conventional grading systems.

Updates on the utility of anterior segment optical coherence tomography in the assessment of filtration blebs after glaucoma surgery

The formation of filtration blebs is the main drainage mechanism for reducing intraocular pressure after traditional incisional glaucoma surgery such as trabeculectomy and non-penetrating deep sclerotomy. Early and short-lasting blebs may also occur after canaloplasty. Bleb formation also plays an important role after the implantation of glaucoma drainage devices, including Minimally Invasive Glaucoma Surgery devices. Anterior segment optical coherence tomography (AS-OCT) is a rapid and non-invasive high-resolution imaging technique that has evolved in recent years to become a routine examination. Anterior segment optical coherence tomography (AS-OCT) provides key information in the assessment and follow-up of glaucoma surgery, especially in the assessment of filtration blebs. Thus, bleb morphology can be qualitatively classified into diffuse, cystic, encapsulated and flattened, and AS-OCT imaging can also provide several quantitative parameters of the bleb, such as total bleb height, bleb fluid-filled cavity height, bleb wall thickness, number of microcysts and trabeculectomy opening size. These parameters could have an impact on clinical management during follow-up because they may predict the success or failure of the surgery in the early and late postoperative periods. Additionally, they may also guide the procedures used to increase filtration and reduce intraocular pressure, such as bleb needling and laser suture lysis.

Animal models and drug candidates for use in glaucoma filtration surgery: A systematic review

Glaucoma, a degenerative disease of the optic nerve, is the leading cause of irreversible blindness worldwide. Currently, there is no curative treatment. The only proven treatment is lowering intraocular pressure (IOP), the most important risk factor. Glaucoma filtration surgery (GFS) can effectively lower IOP. However, approximately 10% of all surgeries fail yearly due to excessive wound healing, leading to fibrosis. GFS animal models are commonly used for the development of novel treatment modalities. The aim of the present review was to provide an overview of available animal models and anti-fibrotic drug candidates. MEDLINE and Embase were systematically searched. Manuscripts until September 1st^, 2021 were included. Studies that used animal models of GFS were included in this review. Additionally, the snowball method was used to identify other publications which had not been identified through the systematic search. Two hundred articles were included in this manuscript. Small rodents (e.g. mice and rats) are often used to study the fibrotic response after GFS and to test drug candidates. Due to their larger eyes, rabbits are better suited to develop medical devices. Novel drugs aim to inhibit specific pathways, e.g. through the use of modulators, monoclonal antibodies, aqueous suppressants or gene therapy. Although most newly studied drugs offer a higher safety profile compared to antimetabolites, their efficacy is in most cases lower when compared to MMC. Current literature on animal models and potential drug candidates for GFS were summarized in this review. Future research should focus on refining current animal models (for example through the induction of glaucoma prior to undertaking GFS) and standardizing animal research to ensure a higher reproducibility and reliability across different research groups. Lastly, novel therapies need to be further optimized, e.g. by conducting more research on the dosage, administration route, application frequency, the option of creating combination therapies, or the development of drug delivery systems for sustained release of anti-fibrotic medication.

Longitudinal changes in complete avascular area assessed using anterior segmental optical coherence tomography angiography in filtering trabeculectomy bleb

Optical coherence tomography angiography (OCTA) is a new technique for non-invasive imaging of blood vessels, allowing combined evaluation of both deep and surface vessels. The purpose of this study was to evaluate the post-trabeculectomy longitudinal changes in complete avascular area (CAA) of filtering blebs using anterior segment (AS-) OCTA and their association with surgical outcomes. This study included 57 eyes of 53 patients who had undergone trabeculectomy with mitomycin C. AS-OCTA images of filtering bleb were acquired at 3 and 6 months after trabeculectomy, and at 1 month in possible cases. CAAs, regions where complete blood flow was not depicted in AS-OCTA images, were evaluated for their presence, extent, and change over time. CAAs were detected in 37 eyes (65%) and 33 eyes (58%) at 3 and 6 months postoperatively, respectively. The extent of CAAs reduced over time after surgery in most cases. No parameters related to CAAs were significantly associated with surgical success (i.e., intraocular pressure (IOP) ≤ 12 mmHg and IOP reduction > 20% without medication). In conclusion, although it is difficult to predict surgical success by CAA itself, AS-OCTA may be useful for the objective evaluation of the vascularity of filtering blebs.

Effect of valproic acid on functional bleb morphology in a rabbit model of minimally invasive surgery

Purpose

To determine the effect of valproic acid (VPA) on bleb morphology and scar characteristics in a rabbit model of minimally invasive glaucoma surgery (MIGS).

Methods

Nine New Zealand white rabbits were subjected to MIGS with intraoperative implantation of the PreserFlo MicroShunt. Rabbits were then administered with subconjunctival injections of phosphate buffered saline (PBS) (n=4) or with VPA (n=5). Bleb morphology was examined by slit-lamp biomicroscopy and in vivo confocal microscopy. Postoperative day 28 tissues were examined by immunohistochemical evaluation and label-free multiphoton microscopy to visualise the collagen matrix, by terminal deoxynucleotidyl transferase dUTP nick-end labelling assay and immunofluorescent labelling for Ki67 expression to detect apoptosis and cell growth, and by real-time quantitative PCR to measure Col1a1, Fn, and Smad6 transcript expression.

Results

VPA-treated blebs were detectable on day 28, while the PBS-treated blebs were not detectable by day 14. VPA-treated blebs were diffuse, extended posteriorly with near normal conjunctival vascularity and featured a combination of reticular/blurred stromal pattern with evidence of relatively large stromal cysts. Instead of the deposition of thick, disorganised collagen fibres characteristic of the PBS bleb, the VPA bleb contained conspicuously thinner collagen fibres which were associated with similarly thinner fibronectin fibres. In corroboration, Col1a1 and Fn mRNA expression was reduced in the VPA blebs, while increased Smad6 expression implicated the disruption of the transforming growth factor beta pathway. Apoptosis and cell growth profiles appeared similar with both treatments.

Conclusions

The results support the application of VPA to enhance bleb morphology associated with good bleb function in MIGS with no apparent cytotoxicity.

Changes in the morphology of the hyperemic blebs in eyes undergone trabeculectomy with mitomycin C after injection of triamcinolone acetonide during one-year follow-up

PURPOSE

To track changes in the morphology of hyperemic blebs in eyes undergone trabeculectomy with mitomycin C 0.02% (MMC) after triamcinolone acetonide (TA) injection.

METHODS

A total of 30 eyes of 30 patients with localized or diffuse hyperemia after trabeculectomy with MMC were enrolled in this prospective interventional case series. Two milligrams of TA were injected at the site of maximal injection. Bleb morphology was graded using Indiana Bleb Appearance Grading Scale (IBAGS), and the Moorfields Bleb Grading System (MBGS) 1 week, 1 month, 3 months, 6 months, and 1 year after injection. Failure was defined as intraocular pressure (IOP) more than predefined target IOP for each eye, need for an additional surgical procedure, IOP less than 6 mmHg, and loss of Light Perception (LP) vision.

RESULTS

A total of 27 patients completed a 1-year follow-up period and were included in the final analysis. The mean time interval from trabeculectomy to injection of TA was 5.98 ± 2.57 weeks. The bleb height and vascularity in the IBAGS system decreased significantly after the intervention (p < 0.05), with an increase in bleb extension (p = 0.006). Using MBGS, the bleb area did not change significantly following TA injection (p = 0.056) but its height and vascularity significantly decreased in both central and peripheral areas and the surrounding conjunctiva (p = 0.032). The development of a mature cataract was the only complication that could be attributed to TA injection.

CONCLUSION

Injection of TA in hyperemic failing blebs improves bleb morphology by decreasing vascularity and height while increasing the extent with an acceptable safety profile.

The Effect of a Triple Combination of Bevacizumab, Sodium Hyaluronate and a Collagen Matrix Implant in a Trabeculectomy Animal Model

Currently available anti-scarring treatments for glaucoma filtration surgery (GFS) have potentially blinding complications, so there is a need for alternative and safer agents. The effects of the intrableb administration of a new combination of the anti-VEGF bevacizumab, sodium hyaluronate and a collagen matrix implant were investigated in a rabbit model of GFS, with the purpose of modulating inflammation, angiogenesis, fibroblast migration and fibrogenesis in the wound healing process. A comparative-effectiveness study was performed with twenty-four rabbits, randomly assigned to the following treatments: (a) biodegradable collagen matrix implant (Olo), (b) bevacizumab-loaded collagen matrix implant (Olo-BVZ), (c) bevacizumab-loaded collagen matrix implant combined with sodium hyaluronate (Olo-BVZ-H5) and (d) sham-operated animals (control). Rabbits underwent a conventional trabeculectomy and were studied over 30 days in terms of intraocular pressure and bleb characterization (height, area and vascularity in central, peripheral and non-bleb zones). Histologic differences among groups were further evaluated at day 30 (inflammation, total cellularity and degree of fibrosis in the area of surgery). Local delivery of bevacizumab (Olo-BVZ and Olo-BVZ-H5) increased the survival of the filtering bleb by 21% and 31%, respectively, and generated a significant decrease in inflammation and cell infiltration histologically 30 days after surgery, without exhibiting any local toxic effects. Olo-BVZ-H5 showed less lymphocyte infiltration and inflammation than the rest of the treatments. Intraoperative intrableb implantation of bevacizumab, sodium hyaluronate and a collagen matrix may provide an improved trabeculectomy outcome in this model of intense wound healing. This study showed an effective procedure with few surgical complications and a novel combination of active compounds that offer new possibilities to improve the efficacy of filtration surgery.

Experimental models of glaucoma filtration surgery

Glaucoma filtration surgery plays an important role in achieving intraocular pressure (IOP) reduction in patients who have high IOP despite maximum medical therapy. Preclinical experimental models of glaucoma filtration surgery contribute a great deal to our knowledge of the wound healing processes that predispose to scarring and may lead to poor outcomes. However, this research needs to be interpreted in the light of the specific study design, animal model and methods used. We review the existing literature addressing various models of experimental glaucoma filtration surgery, discuss the considerations in assessing these models and describe future steps in evaluating potential therapeutics and bleb characteristics that could impact translational research in this field.

Analysis of bleb morphology after CLASS with ultrasound biomicroscopy and clinical grading scale

OBJECTIVE

Filtration in the area subjected to CO₂ laser-assisted sclerectomy surgery (CLASS) is described using ultrasound biomicroscopy (UBM) and the clinical grading scale to evaluate the mechanism of intraocular pressure (IOP) reduction.

METHODS

Twenty-eight patients with open-angle glaucoma underwent CLASS. The Indiana Bleb Appearance Grading Scale evaluation was performed 1 month after surgery to determine bleb height, extent, vascularity, and leakage. UBM was used to describe and measure the surgical area. Bleb morphology, the size of the scleral lake, scleral route, and trabeculodescemetic membrane (TDM) thickness were examined.

RESULTS

One month after CLASS, IOP significantly decreased from 20.46 ± 3.92 mmHg to 12.71 ± 2.99 mmHg, and the anterior chamber depth significantly more shallow, from 2.75 ± 0.36 mm to 2.61 ± 0.33 mm(p < 0.05). Shallow uplift occurred in 71.43% of the blebs, and 64.29% of the blebs were within 1 to 2 h; 82.15% showed mild or moderate vascular hyperemia, and the Seidel test was negative. UBM showed that all eyes had an intact TDM, with a mean thickness of 99.3 ± 22.2 μm; 21 eyes (75%) had L-type (low reflective). The scleral lake anteroposterior length, height, and transversal length were 2.247 ± 1.831 mm, 0.520 ± 0.234 mm, and 3.312 ± 0.423 mm, respectively. The TDM thickness and postoperative IOP were positively correlated, and the size of the scleral lake was not correlated with IOP reduction. Four eyes (14.29%) exhibited cyclodialysis.

CONCLUSION

UBM examination indicated the aqueous humor drainage route. In the early stage after CLASS, subconjunctival and choroidal drainage routes might be the major mechanism underlying IOP reduction. Mild and moderate congestion of bleb blood vessels warrant attention to avoid early bleb scarring.

Trabeculectomy With Extended Subscleral Tunnel Versus Conventional Trabeculectomy in the Management of POAG: A 1-Year Randomized-controlled Trial

PRECIS

This clinical trial compares a modified trabeculectomy technique [extended subscleral tunnel (ESST)] with conventional trabeculectomy [subscleral trabeculectomy (SST)] in terms of success rate and bleb morphology. ESST showed comparable results, with lower incidence of bleb-related complications and need for postoperative antiglaucoma medications.

BACKGROUND

To evaluate the outcome of modified trabeculectomy with extended subscleral tunnel "ESST" versus conventional subscleral trabeculectomy "SST" in the management of uncontrolled primary open-angle glaucoma.

PARTICIPANTS AND METHODS

This is a randomized clinical trial of 40 eyes (40 patients) divided into 2 equal groups. In the first group, a conventional SST with adjuvant 0.3% mitomycin-C was performed. In the second group, the ESST group, an additional 1.00 mm wide longitudinal scleral groove was dissected and excised in the center of the deep scleral bed extending 1.00 mm beyond the posterior margin of the flap. Patients were examined on days 1, 7, 14, 30, 90, 180, and at 1 year, with a special focus on intraocular pressure and bleb morphology. Postoperative ultrasound biomicroscopy was performed to evaluate the surgical area.

RESULTS

Both groups showed a significant reduction in intraocular pressure, with the ESST group showing significantly lower values on days 7, 14, 30, 90, and 180 (P=0.001, 0.004, 0.026, 0.001, and 0.048), but no significant differences on day 1 and at 1 year (P=0.06 and 0.07). The need for postoperative antiglaucoma medications was significantly lower in the ESST group (P=0.043). Visually significant cataract and bleb related complications were more in the SST group (P=0.044 and <0.001). Significantly more eyes in the ESST group showed normal bleb vascularity and wider extent.

CONCLUSIONS

ESST offers a guarded posterior flow with a success rate comparable to that of conventional SST. ESST could minimize bleb-related complications and bleb-dysesthesia with better long-term bleb morphology and vascularity. It could also minimize the need for further adjuvant postoperative antiglaucoma medications.

Surgical site characteristics after CLASS followed by ultrasound biomicroscopy and clinical grading scale: a 2-year follow-up

OBJECTIVE

This study describes the imaging of the filtering area in CO₂ laser-assisted sclerectomy surgery (CLASS) using ultrasound biomicroscopy (UBM) combined with the Indiana Bleb Appearance Grading Scale (IBAGS) and evaluates the mechanism by which CLASS lowers the intraocular pressure (IOP).

METHODS

Twenty-eight cases (28 eyes) of primary open-angle glaucoma that could not be controlled by drugs underwent CLASS. At 1, 3, 6, 12, 18, and 24 months after surgery, IBAGS was used to evaluate the external morphology of the filtering blebs, and UBM was used to describe and measure their internal structure.

RESULTS

During the early period after CLASS, most cases showed diffuse filtering blebs with a serious degree of congestion. At the end of follow-up, most cases did not present filtering blebs. All patients showed an intact and thin trabeculodescemetic membrane (TDM) with an average thickness of 0.094 ± 0.017 mm. The scleral reservoir size gradually decreased over time and tended to stabilize after 18 months. At 3 and 6 months after surgery, 53.57% of the patients had abnormalities in the TDM area, and after laser goniopuncture treatment, the scleral reservoir became slightly larger and the IOP decreased. The TDM thickness was not correlated with postoperative IOP, and the scleral reservoir size was negatively correlated with IOP.

CONCLUSION

During the early phase after CLASS, the subconjunctival and suprachoroidal pathways may be the main mechanisms lowering IOP; over time, internal drainage pathways such as the intrascleral, trabecular-meshwork, and suprachoroidal pathways play greater roles in lowering IOP.

A pilot study for smartphone photography to assess bleb morphology and vasculature post-trabeculectomy

Purpose

The current grading systems used for bleb morphology assessment in patients post-trabeculectomy are based on standardized slit-lamp photographs and anterior segment imaging devices. The lack of availability of these expensive and non-portable devices in resource-deficient settings is a significant deterrent in their widespread utilization for proper post-operative management. The rapidly evolving utilization of smartphone photography has significantly benefited diagnostics of posterior segment disorders and is now being increasingly utilized for monitoring anterior segment pathologies as well as post-surgical course. In this study, we study a novel use of smartphones for bleb photography for assessing the morphological characteristics as vascularity and microcysts.

Methods

In this pilot, observational study, we compared the trabeculectomy bleb images of five subjects, obtained by iPhone X (dual lens) and iPhone 6S (single lens). We captured two image sets with both smartphones first with a focussed torchlight and then with a built-in flash video light.

Results

The images resulting from the newer iPhone X were substantially superior than those from iPhone 6S. For the 12-megapixel dual-camera set-up on the iPhone X, the 1 × lens resulted in better images than the 2 × lens with contrast and overall clarity of the area of interest. While the macro-lens attachment had promising results at 1 × zoom, there is no added advantage of the macro-lens attachment as it resulted in considerable loss of image quality at twice the zoom. Using a 20 D lens helped attain higher magnification and better framing as it reduced the focussing distance needed to get sharp images. The images obtained from both smartphones were of higher quality when illuminated from an external source when compared to the native iPhone flash due to even exposure and fewer autofocus artefacts.

Conclusion

Analyses of all image sets showed that the current generation in-built camera app on IOS and newer iPhone camera optics resulted in high-quality images of the ocular surface with high magnification without any loss in clarity.

Electronic supplementary material

The online version of this article (10.1007/s10792-020-01598-9) contains supplementary material, which is available to authorized users.

Angiographic biomarkers of filtering bleb function after XEN gel implantation for glaucoma: an optical coherence tomography-angiography study

PURPOSE

To evaluate, using optical coherence tomography-angiography (OCT-A), the vascular features of good bleb function after XEN gel implantation (XGI) for uncontrolled glaucoma.

METHODS

Forty-three patients (43 eyes), who underwent XGI, were enrolled. According to the intraocular pressure (IOP) reduction, patients were classified into Group 1 (21 eyes; success) and Group 2 (22 eyes; failure). Optical coherence tomography-angiography (OCT-A) was performed to image the vascularization of the conjunctival bleb-wall. The main outcomes were as follows: vessel displacement areas (VDAs), major vessel displacement area (MVDA; mm2 ), non-flow whole area (NFWA; mm2 ) and bleb-wall vessel density (BVD; %). Co-registered B-scans were also considered to evaluate the bleb-wall cyst-like structure density and area (BCSD, cysts/mm2 ; BCSA, mm2 ), and the bleb-wall thickness (BT, µm).

RESULTS

Mean postoperative follow-up was 7.5 ± 0.14 months; Group 1 and 2 IOP were 14.0 ± 2.5 and 25.3 ± 2.1 mmHg, respectively (p < 0.001). Greater VDA (p < 0.001), MVDA (p = 0.046) and NFWA (p = 0.001) values, and lower BVD (p < 0.001) was found in Group 1 compared to Group 2. Group 1 showed higher BSCD, BSCA and BT values compared to Group 2 (p < 0.001). Postoperative IOP positively correlated with BVD (r = 0.567; p = 0.003), but negatively with VDAs, MVDA (r = -0.581, p = 0.002; r = -0.619, p = 0.001, respectively), BCSD, BCSA (r = -0.580; p = 0.002; r = -0.664; p < 0.001) and BT (r = -0.627, p = 0.001).

CONCLUSION

Successful filtration blebs after XGI present numerous and large areas of vessel displacement within the bleb-wall, along with a rarefied vascular network. These OCT-A features can be considered angiographic biomarkers of a good aqueous humour percolation through the bleb-wall layers.

Bleb grading by photographs versus bleb grading by slit-lamp examination

PURPOSE

Using a bleb-grading system clinically facilitates long-term follow-up of patients with previous glaucoma surgery. Clinical evaluation of these patients can be challenging for untrained ophthalmologists. Morphological bleb configuration might influence planning of follow-up visits in glaucoma patients due to different and individual prognosis after trabeculectomy. In this study, we compared the MaBAGS (Mainz Bleb Appearance Grading System), a classification system for filtering blebs with other classification systems (MBGS/Moorfields Bleb Grading System, IBAGS/Indiana Bleb Appearance Grading Scale) in reference to usability and reliability and compare it to grading by bleb photographs.

METHODS

Forty-two eyes of 31 patients after trabeculectomy were included. Three observers, two senior and one junior observer, graded all blebs using MaBAGS, MBGS and IBAGS during slit-lamp examination. Bleb photographs were reviewed at least 4 weeks after clinical examination. Statistical analysis was performed to determine agreement between the observers using intraclass correlation coefficients.

RESULTS

With MaBAGS, excellent and good levels of agreement were found for vascularity indices, Seidel test and transparency. Parameters for area and height yielded moderate agreement, while indices for conjunctival mobility and microcysts failed to show satisfying levels of agreement. Using MBGS resulted in excellent and good interobserver consistency for parameters regarding subconjunctival blood, Seidel test, and central and peripheral vascularity. Height and nonbleb vascularity reached moderate levels of agreement. Agreement for area parameters was low. With IBAGS, good levels of agreement were found for height and vascularity, and moderate for extent. In all grading systems, consistency was considerably better between the two experienced observers compared to the inexperienced grader.

CONCLUSIONS

MaBAGS shows good reproducibility. Using such a grading system improves precision of the description of a highly variable clinical finding. The reliability of grading by slit-lamp examination exceeds that of grading on photographs.

Nano-structured glaucoma drainage implant safely and significantly reduces intraocular pressure in rabbits via post-operative outflow modulation

Glaucoma is a leading cause of irreversible vision loss predicted to affect more than 100 million people by 2040. Intraocular pressure (IOP) reduction prevents development of glaucoma and vision loss from glaucoma. Glaucoma surgeries reduce IOP by facilitating aqueous humor outflow through a vent fashioned from the wall of the eye (trabeculectomy) or a glaucoma drainage implant (GDI), but surgeries lose efficacy overtime, and the five-year failure rates for trabeculectomy and tube shunts are 25-45%. The majority of surgical failures occur due to fibrosis around the vent. Alternatively, surgical procedures can shunt aqueous humor too well, leading to hypotony. Electrospinning is an appealing manufacturing platform for GDIs, as it allows for incorporation of biocompatible polymers into nano- or micro-fibers that can be configured into devices of myriad combinations of dimensions and conformations. Here, small-lumen, nano-structured glaucoma shunts were manufactured with or without a degradable inner core designed to modulate aqueous humor outflow to provide immediate IOP reduction, prevent post-operative hypotony, and potentially offer significant, long-term IOP reduction. Nano-structured shunts were durable, leak-proof, and demonstrated biocompatibility and patency in rabbit eyes. Importantly, both designs prevented hypotony and significantly reduced IOP for 27 days in normotensive rabbits, demonstrating potential for clinical utility.

Quantitative analysis of functional filtering bleb size using Mask R-CNN

Background

Deep learning has had a large effect on medical fields, including ophthalmology. The goal of this study was to quantitatively analyze the functional filtering bleb size with Mask R-CNN.

Methods

This observational study employed eighty-three images of post-trabeculectomy functional filtering blebs. The images were divided into training and test groups and scored according to the Indiana Bleb Appearance Grading Scale (IBAGS) system. Then, 70 images from the training group were used to train an automatic detection system based on Mask R-CNN and perform a quantitative analysis of the function bleb size. Thirteen images from the test group were used to evaluate the model. During the training process, left and right image-flipping algorithms were used for data augmentation. Finally, the correlation between the functional filtering bleb area and the intraocular pressure (IOP) was analyzed.

Results

The 83 functional filtering blebs have similar morphological features. According to IBAGS, the functional filtering blebs have a high incidence of E1/E2, H1/H2, and V0/V1. Our Mask R-CNN-based model using the selected parameters achieves good results on the training group after a 200-epoch training process. All the Intersection over Union (IoU) scores exceeded 93% on the test group. The Spearman correlation coefficient between the area of functional filtering blebs and the IOP value was −0.757 (P<0.05).

Conclusions

Deep learning is a powerful tool for quantitatively analyzing the functional filtering bleb size. This technique is suitable for use in monitoring post-trabeculectomy filtering blebs in the future.

Structural imaging of conjunctival filtering blebs in XEN gel implantation and trabeculectomy: a confocal and anterior segment optical coherence tomography study

PURPOSE

To describe and compare the conjunctival filtering bleb features after XEN gel implantation and trabeculectomy using anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM).

METHODS

Fifty-two patients who underwent completely successful trabeculectomy (24 eyes) or completely successful XEN gel implantation (28 eyes) were consecutively enrolled. At the sixth-month follow-up, filtering blebs were analyzed with AS-OCT and IVCM. The main outcomes were the following: (i) bleb-wall epithelium cyst-like structure density and area (BECSD, BSCSA), (ii) bleb-wall sub-epithelium cyst-like structure density and area (BSCSD, BSCSA,), (iii) bleb-wall thickness (BT), (iv) bleb-wall epithelial thickness (BET), (v) bleb-wall reflectivity (BR), and (vi) bleb height (BH), for AS-OCT. Mean microcyst density (MMD) and area (MMA) and stromal meshwork reflectivity (SMR) were the IVCM outcomes.

RESULTS

Six-month intraocular pressure was 11.46 ± 3.09 and 10.06 ± 3.39 mmHg in the XEN gel implantation and trabeculectomy, respectively (p > 0.05). At AS-OCT, XEN gel blebs showed lower BH, BT, BET, BR, (p < 0.001), and BECSA values (p < 0.005), and a higher BECSD (p < 0.05) compared with trabeculectomy blebs. At IVCM, MMA and SMR values were lower in the XEN gel implantation, compared with trabeculectomy (p < 0.05). BECSD and BSCSD negatively correlated with BR (p < 0.01; r = - 0.110; p < 0.01; r = - 0.249), whereas BR strongly correlated with SMR (p < 0.001; r = 0.819).

CONCLUSION

Successful filtering blebs after XEN gel implantation appeared flatter and thinner, with a higher number of epithelial cysts and a hypo-reflective bleb wall compared with trabeculectomy. These aspects may depend on the different intra-operative tissue manipulation and/or on different aqueous humor dynamics in the sub-conjunctiva between surgeries.

Novel approaches to model effects of subconjunctival blebs on flow pressure to improve clinical grading systems after glaucoma drainage surgery

Clinical grading systems following glaucoma filtration surgery do not include any effects of the bleb on the intra-ocular pressure and are relatively subjective, therefore carrying the risk of inter and/or intra-observer variability. The main objective of the study is to quantify and model the effect of subconjunctival bleb on flow pressure for assessment of clinical grading following glaucoma surgery. Subconjunctival bleb was created by inserting a tube into ex vivo rabbit eyes via an ab externo approach through the anterior chamber and exiting into the subconjunctival space. Sterile dyed water was injected through the tube into the developing bleb. For the in vitro approach a silicone bleb was created by clamping a circular silicone sheet, injecting dyed water through a fixed resistance outlet tube. Photographic measurements of the bleb height, planform area and pressure were taken as a function of time. Clinical blebs were also collected over a few months. Mathematical algorithm software was used to build the bleb model. Bleb height and volume increase as pressure in the bleb increases. The bleb planform area tended to a constant determined by the section of conjunctiva prior to shunt insertion. These increases were in accordance with the bleb model developed in the Appendix. They show that the pressure in the bleb is related to the resistance of the outflow. The linearity of clinical grading systems is reviewed and a new grading approach is proposed. The pressure in the bleb has a strong dependence on bleb extent, height and a weak dependence on conjunctival thickness. The pressure in a bleb can be estimated from bleb height, radius, and flow rate inlet in agreement with the bleb flow model. These results provide support for an improved bleb categorization system.

Early bleb parameters as long-term prognostic factors for surgical success: a retrospective observational study using three-dimensional anterior-segment optical coherence tomography

Background

The object of this study is to investigate the effect of early bleb parameters measured by three-dimensional anterior-segment optical coherence tomography on the surgical success of trabeculectomy.

Methods

This retrospective study included 45 patients with 19 of exfoliation glaucoma, 17 of primary open angle glaucoma, 4 of neovascular glaucoma, 4 of uveitic glaucoma and 1 of glaucoma caused from familial amyloid polyneuropathy who underwent trabeculectomy. Bleb parameters, such as total bleb height, the position and the width of filtration openings on the scleral flap, bleb wall thickness, fluid-filled cavity height, and bleb wall intensity were assessed by three-dimensional anterior-segment optical coherence tomography 0.5 months after trabeculectomy, and were subjected to a Cox proportional hazard model as potential prognostic factors. Surgical success was defined as: IOP < 21 mmHg (A), < 18 mmHg (B), < 15 mmHg (C) with (qualified success) or without medication (complete success). Complete failure was defined as hypotony and additional glaucoma surgeries required.

Results

The width of filtration openings was identified as a prognostic factor for all criteria. By multivariable analysis, the width of the filtration openings was a prognostic factor in all criteria tested, and the preoperative IOP were significant prognostic factors for surgical success in qualified success in criteria B and C. Separate from the median widths of filtration openings, wide filtration opening showed significant survival ratio for qualified success in criteria A and B and for complete success in all criteria, respectively.

Conclusions

The width of filtration opening at an early stage is a prognostic factor for surgical success of trabeculectomy.

Study of the Efficacy and Safety of Contact Lens Used in Trabeculectomy

Purpose

To investigate the efficacy and safety of soft bandage contact lens used in trabeculectomy.

Methods

This was a prospective, randomized study which enrolled 200 glaucoma patients (200 eyes). Patients were randomized into Group 1, using contact lens after trabeculectomy, and Group 2, without contact lens. The primary outcome measurement was the comparison of success rates at 12 months after surgery. Qualified surgical success was defined as a postoperative intraocular pressure (IOP) value of 6–21 mmHg with or without topical antiglaucoma medication use at the last follow-up visit. Complete success was defined as the IOP between 6 and 21 mmHg without any antiglaucoma medication at the last follow-up visit. Postoperative data included IOP values, best-corrected visual acuity (BCVA), number of antiglaucoma medications, complications related to surgery, and bleb characteristics.

Results

There were statistically significant differences between Groups 1 and 2 in mean IOP values at 3, 6, and 12 months after surgery (P < 0.05). The 12-month life table rates for qualified surgical success were 94.7% and 86.3% in Groups 1 and 2, respectively (P=0.045). The 12-month life table rates for complete surgical success were 89.6% and 80.0% in Groups 1 and 2, respectively (P=0.042). At 12 months after surgery, the mean numbers of antiglaucoma medications were 0.3 ± 0.4 and 0.5 ± 0.6, respectively. (P=0.001). At the 12-month visit, the maximal bleb area was significantly different between groups (P=0.044), with Group 1 exhibiting a more diffused bleb area. Encysted blebs were observed in 7 (7%) eyes in Group 1 and 17 (17%) eyes in Group 2, with statistically significant differences (P=0.030). The 12-month life table rates for qualified surgical success were 94.7% (91 eyes) and 86.3% (82 eyes) in Groups 1 and 2, respectively (P=0.045).

Conclusions

Bandage contact lens is a safe and effective device after fornix-based trabeculectomy.

Evaluation of Functional Filtering Bleb Using Optical Coherence Tomography Angiography

Purpose

This study investigated whether filtering blebs can be evaluated using optical coherence tomography angiography (OCT-A) and compared vascularity parameters with conventional bleb grading systems.

Methods

A total of 92 patients with glaucoma, who underwent mitomycin C–augmented trabeculectomy, were enrolled in this study, and 92 eyes were assessed in total. The participants underwent OCT-A in external mode and anterior segment photography for bleb evaluation. For evaluation of bleb vascularity, a blinded observer carefully drew the bleb area on the original OCT-A image using a semiautomated program that calculated the color and brightness densities of the selected area. A blinded observer also classified the grades of the bleb vessels using the Indiana Bleb Appearance Grading Scale (IBAGS) and Moorfields Bleb Grading System (MBGS). The vascularity parameters using OCT-A were compared with the IBAGS and MBGS results. In addition, the correlation between intraocular pressure (IOP) and the bleb vascularity parameters was assessed.

Results

Vessel density measured by OCT-A demonstrated excellent inter- and intraobserver reproducibility. The color and brightness densities were positively correlated with the IBAGS and MBGS vascularity scores. There was no difference in accuracy when predicting IOP risk using vascularity scores from the IBAGS and MBGS or when estimating IOP risk using the color and brightness densities on the net reclassification index.

Conclusions

Bleb evaluation using OCT-A can evaluate vessel vascularity and showed correlation to the IBAGS and MBGS vascularity grading.

Translational Relevance

Bleb vascularity measurements using OCT-A could potentially provide objective and quantitative vessel parameters for bleb evaluation following trabeculectomy.

Bleb Morphology After Mitomycin-C Augmented Trabeculectomy

PURPOSE

The main aim of this article was to study the longitudinal correlation between the clinical, morphological appearance of filtering blebs with anterior segment optical coherence tomography (AS-OCT) in the early postoperative period.

METHODS

Thirty eyes of 30 glaucoma patients scheduled for first-time trabeculectomy with 0.02% mitomycin-C were consecutively enrolled. The filtering blebs were evaluated clinically according to a grading system and with AS-OCT at day 1 and weeks 1, 2, 3, 4, and 12 following surgery. Bleb wall thickness (BWT) and bleb cavity height (BCH) were analyzed by means of horizontal and vertical AS-OCT scans.

RESULTS

Nineteen eyes (63%) had functioning blebs without any further surgical intervention. intraocular pressure changed from 18.4±1.3 mm Hg with preoperatively applied glaucoma medication to a mean of 9.75±1.4 mm Hg at all follow-ups postoperatively without medication. Mean BWT during follow-up was 575±47 μm; mean BCH was 295±72 μm. Nine filtering blebs (30%) showed encapsulation requiring a bleb needling. This was recognized clinically at week 3 in 4, and at week 4 in 5 cases. The tendency towards encapsulation was seen much earlier with AS-OCT, already showing a statistically thinner BWT (P=0.036) at week 1 and a higher BCH (P=0.005) at week 2 postsurgery, compared with the group with functioning blebs. As of week 3, intraocular pressure increased and was statistically significantly higher (P=0.016) compared with the group with functioning blebs. Two patients (7%) showed early scarring.

CONCLUSION

AS-OCT allows an analysis of the clinically invisible deeper layers of the filtering bleb. Characteristics of encapsulation, like higher blebs with thinner bleb walls, are sooner recognized than the clinical appearance. This might benefit the management of the postoperative period after trabeculectomy and the long-term outcome.

Longitudinal bleb morphology in anterior segment OCT after minimally invasive transscleral ab interno Glaucoma Gel Microstent implantation

Purpose

Like the classic trabeculectomy, the minimally invasive, ab interno XEN Glaucoma Gel Microstent (XEN‐GGM) creates a filtration bleb in the conjunctiva. The goal of this study was to investigate internal bleb morphology over time with anterior segment optical coherence tomography (AS‐OCT) after XEN‐GGM implantation.

Methods

In a prospective, single‐centre, single‐armed cohort study, blebs were characterized using AS‐OCT in 78 eyes of 60 patients at day 1, at weeks 1 and 2 and at months 1, 3, 6, 9 and 12 after XEN‐GGM implantation in patients with open‐angle glaucoma. Morphological bleb characteristics were correlated with IOP and surgical success.

Results

Anterior segment optical coherence tomography data indicate early and late bleb changes in the course of 12 months. Uniform blebs in AS‐OCTs showed higher IOPs at all examinations between week 1 (17.7 ± 4.8 mmHg versus 11.3 ± 7.1 mmHg, p = 0.001) and month 3 (16.4 ± 6.1 versus 13.4 ± 6.1, p = 0.04). Subconjunctival tissue separation bleb morphology was associated with lower mean IOPs during the course of 12 months (r = −0.75, p = 0.031). Predictors for surgical failure at month 12 were microcystic multiform bleb morphology in AS‐OCT at month 3 (60% versus 15%, relative risk 4.0, p = 0.043) and uniform bleb morphology at month 9 (33% versus 23%, relative risk 1.4, p = 0.015).

Conclusion

Bleb appearance after XEN surgery seems to be different to classic trabeculectomy literature. The present data suggest correlation of IOP and surgical long‐term success with bleb morphology in AS‐OCT. Prevalence of small diffuse cysts is directly associated with lower IOPs, while cystic encapsulation at 3 months predicts higher surgical failure.

Supraciliary versus intrascleral implantation with hema implant (Esnoper V-2000) in deep sclerectomy: a multicenter randomized controlled trial

PURPOSE

To compare the supraciliary versus intrascleral implantation of the hema implant (Esnoper V-2000) in terms of the efficacy and safety in nonpenetrating deep sclerectomy (NPDS).

PATIENTS AND METHODS

Prospective, randomized, unmasked, competitive and multicenter clinical trial. Eighty-three eyes from 83 patients suffering from open-angle glaucoma (40 males, 43 females) were enrolled and followed up for 12 months. Main outcome measures were best-corrected visual acuity (BCVA), intraocular pressure (IOP), perimetry (mean defect, MD and Visual Field Index, VFI), pachymetry, number of antiglaucoma medications and analysis of blebs according Moorfields Bleb Grading.

RESULTS

The IOP was significantly reduced in both groups from 23.74 ± 6.9 mmHg (implant sutured to the sclera, group 1) and 23.46 ± 6.47 mmHg (implant placed in the suprachoroidal space, group 2) to 15.43 ± 4.27 mmHg (p < 0.001) and 14.62 ± 3.64 mmHg (p < 0.001), respectively. There were no statistically significant differences in mean IOP values between the groups a year after the surgery (p = 0.581). BCVA did not show statistical differences in comparison with baseline (p = 0.09, group 1; p = 0.42, group 2). The mean number of antiglaucoma medications was reduced in both groups from 2.58 ± 0.04 and 2.68 ± 0.02 before the surgery to 0.32 ± 0.76 and 0.24 ± 0.66 after surgery.

CONCLUSION

Nonpenetrating deep sclerectomy using hema implant (Esnoper V-2000) is safe and effective regardless of the positioning of the implant. We achieved IOP decrease and reduction in antiglaucoma medications during the first year after surgery without significant differences between both techniques.

The CLASS Surgical Site Characteristics in a Clinical Grading Scale and Anterior Segment Optical Coherence Tomography: A One-Year Follow-Up

Purpose

We combined a clinical grading scale and swept source anterior segment OCT to describe the successful and failed CLASS.

Material and Methods

23 patients in the successful group and 17 patients in the failed group were compared in terms of the IBAGS grades and AS-OCT findings at one, three, and twelve months postoperatively.

Results

The majority in the successful group presented shallow blebs (91%, 57%, and 52% at 1M, 3M, and 12M, resp.). 59% of the failed group presented no bleb (H0 E0) from the early postoperative period with the rate increasing to 88% at 3M and 100% at 12M. The scleral lake was detected in all the successful patients. The successful group showed significantly higher rates of TDM integrity (P < 0.001), IF (P < 0.001), and SCF (P < 0.05), but there were no significant differences in the rates of microcysts between the groups (P > 0.05). We found a significant decrease in the SL anteroposterior extent (P=0.003) and SL height (P < 0.001) over time, with no significant correlation between the above parameters and IOP.

Conclusions

The subconjunctival bleb may be a sign of the successful CLASS when it matches the AS-OCT findings of TDM integrity, maintained scleral lake, and intrascleral fluid. A validated OCT pixel intensity measurement is required to evaluate the bleb reflectivity.

Comparison of intensity, phase retardation, and local birefringence images for filtering blebs using polarization-sensitive optical coherence tomography

Polarization-sensitive optical coherence tomography (PS-OCT) allows the recording of depth-resolved polarimetric measurements. It has been reported that phase retardation and local birefringence images can noninvasively detect fibrotic area in blebs after glaucoma surgery. Evaluation of scar fibrosis in blebs is important not only for predicting bleb function, but also for planning revision trabeculectomy. Herein, we characterize the intensity, phase retardation, and local birefringence images of blebs using PS-OCT. A total of 85 blebs from 85 patients who had undergone trabeculectomy were examined. Both phase retardation and local birefringence images detected fibrotic changes in blebs after glaucoma surgery. Phase retardation images detected slight fibrotic change during the early stage after surgery, whereas local birefringence images showed localized fibrotic tissue. There are two main patterns of local birefringence image changes in blebs: plate-like birefringence changes and diffuse changes. The area of plate-like birefringence change was significantly larger in poorly functioning blebs and is thus correlated with bleb function. These data suggest that the plate-like fibrotic change evaluation by PS-OCT may be useful not only for noninvasive evaluation of fibrotic scar tissue in blebs, but also for developing strategies for revision trabeculectomy.

Relationship between age and surgical success after trabeculectomy with adjunctive mitomycin C

PURPOSE

To investigate whether there is any effect of age on bleb morphology and surgical success after trabeculectomy with adjunctive Mitomycin C (MMC).

METHODS

A total 143 eyes of 123 patients were divided into two groups: group 1 ( ≤ 60 years old, n = 85) and group 2 ( > 60 years old, n = 58). Kaplan-Meier survival curve analysis was used to assess long-term surgical success according to "complete success" (intraocular pressure (IOP) reduction ≥ 30% without medications) and "qualified success" criteria (IOP reduction ≥ 30%, with or without medications) between the two groups. Cox proportional hazard models were used to examine the factors associated with surgical success. Bleb morphology was evaluated by height, extent and vascularity at postoperative 1 month, 3 months, 6 months, and 12 months.

RESULTS

The younger-age group (group 1) showed significantly better results, in terms of both complete success and qualified success, than did the older-age group (group 2) (p < 0.001 and p = 0.01, respectively). Age and preoperative anti-glaucoma medications were the factors related to complete success (p = 0.001). Also, there were significant differences in height, extent and vascularity of bleb between the two groups (p = 0.038, p = 0.002 and p = 0.006, respectively).

CONCLUSION

The long-term surgical outcome after trabeculectomy with MMC was better in the younger-age group than in the older-age group. Specifically, the younger-age group showed a more prominent and more localized bleb with less vascularity.

Functional evaluation of the filtering bleb by ultrasound biomicroscopy after trabeculectomy with mitomycin C

AIM

To study the role of ultrasound biomicroscopy (UBM) in the assessment of the bleb function after trabeculectomy with mitomycin C (MMC).

METHODS

This was a cross-sectional study including all cases had undergone trabeculectomy with MMC 0.2 mg/mL for 3min. Participants were recruited from the follow-up cases at Department of Ophthalmology, Tanta University in the period from August 2015 to August 2016. Full history taking and ophthalmological examination were performed. Intraocular pressure (IOP) was measured using Goldmann applanation tonometry and the history of prescribed postoperative antiglaucoma medications was recorded. Accordingly, the trabeculectomy blebs were divided clinically into successful blebs when the IOP post-operative was ≤18 mm Hg without medications. Scanning examination of the filtering bleb using UBM examination was performed at the period from 2 to 36mo after trabeculectomy (13.6±9.7mo).

RESULTS

This study included 33 trabeculectomy filtering blebs of 25 patients (9 males and 16 females). The mean age of patients was 53.2±14.2y (range 25-71y). We had 20 eyes with complete success, 9 eyes with qualified success, and 4 eyes with failure after trabeculectomy with MMC. The blebs were classified into successful blebs (IOP ≤18 mm Hg without antiglaucoma medications), others were classified into qualified successful and failed blebs. There was a significant correlation between certain UBM findings (intra-bleb reflectivity, draining sub-scleral tract, bleb height, and intrableb fluid cysts) and cases with different grades of clinical functional success (P<0.01).

CONCLUSION

UBM is an objective tool in the functional assessment of the post-trabeculectomy filtering bleb through a significant correlation between certain UBM parameters and the different grades of clinical functional success.

Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy

Background: To determine the predictive value of postoperative bleb morphological features and intraocular pressure (IOP) on the success rate of trabeculectomy.

Methods: In this prospective interventional case series, we analyzed for one year 80 consecutive primary open angle glaucoma patients who underwent mitomycin-augmented trabeculectomy. Bleb morphology was scored using the Indiana bleb appearance grading scale (IBAGS). Success was defined as IOP ≤15 mmHg at 12 months. We applied a multivariable regression analysis and determined the area under the receiver operating characteristic curve (AUC).

Results: The mean age of participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430) with equal gender distribution (P=0.911). IOPs on day 1, 7 and 30 were similar in both (P= 0.193, 0.639, and 0.238, respectively.) The AUC of IOP at day 1, day 7 and 30 for predicting a successful outcome was 0.355, 0.452, and 0.80, respectively. The AUC for bleb morphology parameters of bleb height, extension, and vascularization, on day 14 were 0.368, 0.408, and 0.549, respectively. Values for day 30 were 0.428, 0.563, and 0.654. IOP change from day 1 to day 30 was a good predictor of failure (AUC=0.838, 95% CI: 0.704 to 0.971) with a change of more than 3 mmHg predicting failure with a sensitivity of 82.5% (95% CI: 68 to 91%) and a specificity of 87.5% (95% CI: 53 to 98%).

Conclusions: IOP on day 30 had a fair to good accuracy while bleb features failed to predict success except bleb vascularity that had a poor to fair accuracy.  An IOP increase more than 3 mmHg during the first 30 days was a good predictor of failure.

Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy

Background: To determine the predictive value of postoperative bleb morphological features and intraocular pressure (IOP) on the success rate of trabeculectomy. Methods: In this prospective interventional case series, we analyzed for one year 80 consecutive primary open angle glaucoma patients who underwent mitomycin-augmented trabeculectomy. Bleb morphology was scored using the Indiana bleb appearance grading scale (IBAGS). Success was defined as IOP ≤15 mmHg at 12 months. We applied a multivariable regression analysis and determined the area under the receiver operating characteristic curve (AUC). Results: The mean age of participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430) with equal gender distribution (P=0.911). IOPs on day 1, 7 and 30 were similar in both (P= 0.193, 0.639, and 0.238, respectively.) The AUC of IOP at day 1, day 7 and 30 for predicting a successful outcome was 0.355, 0.452, and 0.80, respectively. The AUC for bleb morphology parameters of bleb height, extension, and vascularization, on day 14 were 0.368, 0.408, and 0.549, respectively. Values for day 30 were 0.428, 0.563, and 0.654. IOP change from day 1 to day 30 was a good predictor of failure (AUC=0.838, 95% CI: 0.704 to 0.971) with a change of more than 3 mmHg predicting failure with a sensitivity of 82.5% (95% CI: 68 to 91%) and a specificity of 87.5% (95% CI: 53 to 98%). Conclusions: IOP on day 30 had a fair to good accuracy while bleb features failed to predict success except bleb vascularity that had a poor to fair accuracy.  An IOP increase more than 3 mmHg during the first 30 days was a good predictor of failure.

Characteristics of early filtering blebs that predict successful trabeculectomy identified via three-dimensional anterior segment optical coherence tomography

Background/aims

To identify the cross-sectional characteristics of filtering blebs at 2 weeks post-trabeculectomy associated with intraocular pressure (IOP) control at 1 year post-trabeculectomy.

Methods

Ninety-nine eyes of 94 patients who had undergone primary trabeculectomy were included in this retrospective consecutive case series study. Surgical success was defined as an IOP ≤15 mm Hg and a >20% reduction in IOP without glaucoma medication or additional glaucoma surgeries at 1 year post-trabeculectomy. Subjects were classified into two groups according to whether surgery was successful or unsuccessful. Blebs were examined using swept-source three-dimensional anterior segment optical coherence tomography and evaluated for quantitative parameters, including maximum height, maximum wall thickness and ratio of hyporeflective space of the wall, as well as qualitative parameters, including multiple parallel hyporeflective layers within the wall (striping phenomenon), decreased visibility of the sclera underlying the bleb (shading phenomenon) and cyst-like structures of the wall.

Results

Seventy-seven eyes (77.8%) were assigned to the successful group and 22 (22.2%) to the unsuccessful group. Univariate analysis showed significant differences between the groups regarding maximum bleb height (p=0.044), maximum bleb wall thickness (p=0.017) and the striping phenomenon of the bleb wall (p=0.007). Multivariate logistic regression analysis confirmed that the striping phenomenon at 2 weeks post-trabeculectomy was significantly associated with success at 1 year post-trabeculectomy (OR 3.405; 95% CI 1.059 to 10.947; p=0.040).

Conclusion

Taller blebs with thicker walls that showed the striping phenomenon at 2 weeks post-trabeculectomy appeared to predict good IOP control at 1 year post-trabeculectomy.

Effect of Porcine Chondrocyte-Derived Extracellular Membrane (CDECM) on Postoperative Wound Healing in an Experimental Rabbit Model of Glaucoma Filtration Surgery

PURPOSE

We investigated whether a chondrocyte-derived extracellular membrane (CDECM) could reduce postoperative scar formation in an experimental rabbit model of glaucoma filtration surgery.

METHODS

Thirty-six male New Zealand white rabbits underwent experimental glaucoma filtration surgeries on the right eye and were randomly divided into the following two treatment groups: the CDECM group was treated with subconjunctival injections of 0.1ml CDECM (25 mg/ml; n = 18 eyes), and the operation (OP) group was treated with subconjunctival injections of 0.1 ml balanced salt solution (n = 18 eyes). The left eyes were used as controls (n = 36 eyes). The effects of the CDECM on the experimental rabbit model were investigated using histopathological, immunochemical analyses and Western blotting analyses of the inflammation, fibrosis and angiogenesis.

RESULTS

On the 14th postoperative day, the eyes of the CDECM group displayed reduced vascularity and fibrosis compared with the OP group. The vascular endothelial growth factor (VEGF), CD31 and TNFβ immunostaining were also reduced in the CDECM group. The level of TNFα mRNA was increased in the OP group. On the 28th postoperative day, the eyes of the CDECM group also exhibited reduced vascularity and less inflammation and fibrosis than those of the OP group. The expressions of VEGF, CD31, macrophage, TNFβ and NF-κB p65 were also decreased in the CDECM group. The levels of TNFα mRNA significantly differ, and the level of matrix metallopeptidase 9 (MMP9) was increased in the OP group. To determine the specific upstream pathway that was associated with NF-κB activation due to glaucoma filtration surgery, we measured Akt, PKCs and MAPKs signaling. The phosphorylation of p38 MAPK was increased in the OP group, whereas this expression was decreased by CDECM treatment.

CONCLUSIONS

CDECM seems to suppress angiogenesis, inflammation and fibrosis, which were related to wound healing in the experimental rabbit model of glaucoma filtration surgery. This effect, resulting from the inhibition of NF-κB expression, may be the blocking of the p38 MAPK signaling pathway.

The relationship of bleb morphology and the outcome of needle revision with 5-fluorouracil in failing filtering bleb

To investigate the risk factors for failure of needling revision with 5-fluorouracil (5-FU) and to identify the correlation of outcomes of needling revision and the morphological features of dysfunctional filtration blebs using Moorfields bleb grading system.This retrospective, nonrandomized, comparative case-control study included 41 consecutive patients (41 eyes) who underwent 5-FU needling revision for failed or failing filtration blebs between July 2012 and August 2014 in Chang Gung Memorial Hospital, a referral center in Taiwan. The main outcome measures were the bleb survival and the correlation factors of bleb morphology before revision. The secondary outcome measure was the identification of any study factor associated with bleb failure.Forty-one eyes of 41 patients were included in this study. The most frequent glaucoma diagnoses were 10 cases (24%) of neovascular glaucoma and 8 cases (19%) of chronic open-angle glaucoma. Survival of bleb at 6, 12, and 24 months was 42%, 39%, and 23%. Fourteen cases (34%) maintained overall success at the last follow-up, with an average follow-up of 22.7 ± 9.4 months (range: 12-48 months). The central bleb area and height were significantly different between the successful needling group and the failed needling group (P = 0.03 and 0.04, respectively). Further trend test confirmed that smaller central bleb extension and flatter height were associated with a higher chance of failure (P = 0.02 and 0.02, respectively). Time from initial trabeculectomy to needling of less than 4 months and higher intraocular pressure (IOP) in the first postoperative week also led to significantly higher risk for failure (P = 0.01 and 0.03, respectively).A small central area and the flat height of dysfunctional blebs were more likely to fail after the needle revision. Cautious case selections, taking account of the time from the initial filtering surgery and postoperative IOP, may improve the surgical outcome.

Subconjunctival Delivery of Dorzolamide-Loaded Poly(ether-anhydride) Microparticles Produces Sustained Lowering of Intraocular Pressure in Rabbits

Topical medications that inhibit the enzyme carbonic anhydrase (CAI) are widely used to lower intraocular pressure in glaucoma; however, their clinical efficacy is limited by the requirement for multiple-daily dosing, as well as side effects such as blurred vision and discomfort on drop instillation. We developed a biodegradable polymer microparticle formulation of the CAI dorzolamide that produces sustained lowering of intraocular pressure after subconjunctival injection. Dorzolamide was ion paired with sodium dodecyl sulfate (SDS) and sodium oleate (SO) with 0.8% and 1.5% drug loading in poly(lactic-co-glycolic acid) (PLGA), respectively. Encapsulating dorzolamide into poly(ethylene glycol)-co-poly(sebacic acid) (PEG3-PSA) microparticles in the presence of triethylamine (TEA) resulted in 14.9% drug loading and drug release that occurred over 12 days in vitro. Subconjunctival injection of dorzolamide-PEG3-PSA microparticles (DPP) in Dutch belted rabbits reduced IOP as much as 4.0 ± 1.5 mmHg compared to untreated fellow eyes for 35 days. IOP reduction after injection of DPP microparticles was significant when compared to baseline untreated IOPs (P < 0.001); however, injection of blank microparticles (PEG3-PSA) did not affect IOP (P = 0.9). Microparticle injection was associated with transient clinical vascularity and inflammatory cell infiltration in conjunctiva on histological examination. Fluorescently labeled PEG3-PSA microparticles were detected for at least 42 days after injection, indicating that in vivo particle degradation is several-fold longer than in vitro degradation. Subconjunctival DPP microparticle delivery is a promising new platform for sustained intraocular pressure lowering in glaucoma.

Biodegradable collagen matrix implant versus mitomycin-C in trabeculectomy: five-year follow-up

Background

Clinical studies comparing trabeculectomy augmented with Ologen implant (OLO) versus trabeculectomy plus mitomycin-C (MMC) show contradictory results. To obtain long-term data, we report an extended 5-year follow-up trial evaluating the safety and efficacy of OLO as adjuvant compared to low-dosage MMC in trabeculectomy.

Methods

Forty glaucoma patients (40 eyes) assigned to trabeculectomy with MMC or Ologen. Primary outcome: target IOP at ≤21, ≤17 and ≤15 mmHg; complete and qualified success endpoint rates. Secondary outcomes: visual acuity (VA), mean deviation (MD), bleb evaluation, according to Moorfields Bleb Grading System (MBGS); spectral domain OCT (SD-OCT) bleb examination; number of glaucoma medications; frequency of postoperative complications.

Results

The mean preoperative IOP was 26.7(±5.2) in MMC and 27.3(±6.0) in OLO eyes. Mean 60-month percentage reduction in IOP was significant in both groups [40.9 (±14.2) and 42.1(±13.3) P = 0.01], with an endpoint value of 15.2 (±3.2) and 15.8 (±2.3) mmHg in MMC and OLO, respectively. Complete success rates at ≤ 21 mmHg target IOP were 65 % and 70 %, at ≤17 mm Hg 60 % and 55 %, and at the ≤15 mm Hg target IOP 35 % and 45 % in MMC and OLO, respectively.

The Kaplan–Meier curves did not differ both for complete and qualified success at any target IOP, with no significant endpoint intergroup difference at ≤ 15 mm Hg (log-rank P = 0.595).The intergroup MBGS scores differed due to reduced central and peripheral vascularity in MMC group (P = 0.027; P = 0.041).

SD-OCT analysis denied differences in bleb height between MMC vs OLO (140.5 ± 20.3 μ vs 129.2 ± 19.3 μ respectively; P =0.079).

Mean antiglaucoma medications were significantly reduced (P < 0.0005) from 2.5 (±0.3) to 1.2 (±0.4) in MMC and from 2.6 (±0.2) to 1.4 (±0.3) in OLO group, with no intergroup differences (P = 0.08).

Six (30 %) cystic thin avascular blebs without oozing were recorded in the MMC group and 2 (10 %) in the OLO group, without intergroup difference (P = 0.235).

Conclusions

Our extended follow-up results confirm that Ologen implant yields efficacy and long-term success rates quite similar to MMC, with at least equivalent safety.

Electronic supplementary material

The online version of this article (doi:10.1186/s12886-016-0198-0) contains supplementary material, which is available to authorized users.

Evaluation of Filtering Bleb Function after Trabeculectomy with Mitomycin C Using Biomicroscopy, Anterior Segment Optical Coherence Tomography and In Vivo Confocal Microscopy

OBJECTIVES

To analyze and assess compatibility of trabeculectomy filtering bleb characteristics and appearances using biomicroscopy, anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM).

MATERIALS AND METHODS

Twenty-eight eyes of 28 patients who underwent glaucoma filtering surgery with mitomycin C in our clinic between 2009 and 2013 were evaluated. Morphological appearances of the blebs on slit-lamp biomicroscopy were defined according to the Moorfields bleb classification system. For the internal tissue assessment of blebs, AS-OCT and IVCM were performed. Bleb biometric parameters such as length, height and bleb wall thickness were assessed by AS-OCT; conjunctival epithelial-stromal cyst, structural network of conjunctival stroma and vascularisation were examined with IVCM. The relation between biomicroscopic morphological staging and bleb characteristics detected on AS-OCT and IVCM were assessed.

RESULTS

The mean age of the 28 patients (16 male, 12 female) was 57.2±15.9 (19 to 79) years. The mean time elapsed between surgery and examination was 29.2±19.2 (6 to 68) months. According to biomicroscopic appearance, 17 (60.7%) blebs were functional (13 diffuse, 4 microcystic), whereas 11 (39.3%) blebs were non-functional (9 flat, 2 encapsulated). In the comparison of non-functional and functional blebs, functional blebs were found to be superior in terms of biometric parameters on AS-OCT assessment (p<0.05). Higher number of epithelial and stromal cysts and less vascularisation were detected by IVCM in functional blebs when compared with non-functional blebs (p<0.05).

CONCLUSION

Biomicroscopic appearances and characteristics on AS-OCT and IVCM of filtration blebs are consistent with each other. Besides biomicroscopic examination, which is an easy and practical method for determining bleb morphology, cross-sectional images obtained by AS-OCT and IVCM provide objective data regarding internal structure and functional features of blebs.

Thermography: a new option to monitor filtering bleb function?

PURPOSE

To evaluate the filtering bleb function after trabeculectomy using a new ocular surface thermography device.

METHODS

Thirty-five eyes of 35 patients after trabeculectomy were included in this prospective study. The filtering bleb function was tested with a new ocular surface-oriented, infrared radiation thermographic device in a noncontact manner (TG 1000). The eyes were classified into poorly controlled and well-controlled intraocular pressure (IOP) groups according to the patients' postoperative IOP. According to Kawasaki and colleagues, the mean temperature decrease in the filtering bleb (TDB) for evaluating bleb function was used, where TDB=(mean temperature of the temporal and nasal bulbar conjunctiva)-(mean temperature of the filtering bleb). Furthermore, the filtering bleb was evaluated during 10 seconds of eye opening and a new parameter was introduced, the TB10sec. TDB and TB10sec were analyzed statistically.

RESULTS

The TDB was 0.911°C (±0.467) and the TB10sec was -1.027°C (±0.312) in the well-controlled IOP group. The TDB was 0.599°C (±0.499), and the TB10sec was -0.623°C (±0.265) in the poorly controlled IOP group, respectively. The difference in TDB (P=0.045), as well as that of TB10sec (P<0.001), between the well-controlled and poorly controlled IOP groups was significant.

CONCLUSIONS

Temperature decrease in the filtering bleb provides information about its function. Because of the easy handling and reproducible measurements, thermography using Tomey TG 1000 may be a useful tool in the evaluation of filtering bleb function.