A pilot study of a system for grading of drainage blebs after glaucoma surgery

"Intrableb pigmentation following XEN implantation: A case series"

PURPOSE

To evaluate the incidence and to describe the characteristics of the intrableb pigmentation (IBP) following XEN63 implantation.

METHODS

Retrospective case series of three eyes presenting a pigment dispersion in the filtering bleb after a XEN63 implantation for uncontrolled IOP. Demographic, clinical and imaging data were obtained from medical records.

RESULTS

Three out of 40 patients who underwent XEN implantation (average age 70.67 years) showed an IBP during the 12 months postoperative period. The mean time of IBP onset was 50 days (range, 15-90). The slit lamp examination showed two IBP patterns: a "diffuse" pattern (2 patients) with multiple spots of pigmentation inside the bleb; a "punctiform" pattern (1 patient), with a single spot at the distal end of the device. The AS-OCT imaging confirmed the presence of IBP appearing as a hyperreflective spot/s in the context of the filtering bleb. The patient with the punctiform IBP experienced a distal XEN ostium obstruction with a decrease in bleb function. In one case the diffuse IBP occurred after a successful needling procedure. All the patients' IOP reported at the end of the follow-up was below 21 mmHg.

CONCLUSION

The development of IBP might occur after XEN implantation in various times and with different patterns. The IBP pattern can provide meaningful clues on the bleb filtering function. A proper follow-up based on slit lamp biomicroscopy, IOP measurement, and AS-OCT imaging is recommended to manage potential complications related to IBP.

Sonographic bleb visualisation after PAUL glaucoma implant surgery

BACKGROUND/AIMS

Bleb characteristics in the area around the plate following glaucoma drainage device (GDD) surgery are difficult to evaluate on slit lamp examination. Ultrasound sonography could be used for more detailed visualisation. The aim of this study was to describe bleb configuration after PAUL glaucoma implant (PGI) surgery and evaluate the possible correlation with intraocular pressure (IOP) in order to derive new markers for evaluating GDD function.

METHODS

Patients underwent a 15 MHz ultrasound examination (Compact Touch, Quantel Medical) after undergoing PGI implantation. The filtering bleb dimensions were measured and bleb configuration was assessed along with documentation of all clinical data.

RESULTS

A total of 70 eyes from 65 patients were included. 55 eyes (78.6%) had a double-layered bleb whereas 15 eyes (21.4%) had a bleb with only one compartment (six eyes, 8.6% above; nine eyes, 12.9% below the plate). The total height of both compartments averaged 3.52 mm. The average IOP was 13.03 mm Hg. There was a significant correlation between single and double-layered blebs (p<0.01) with regard to IOP (one compartment: 16.47 mm Hg vs two compartments: 12.09 mm Hg). There was no significant correlation between total bleb height (p=0.143) or bleb extension (T: p=0.629; L: p=0.742). However, total bleb height showed an inverse association with IOP. Blebs with a height >2 mm had significantly lower mean IOP than those having <2 mm bleb heights (p=0.041).

CONCLUSIONS

Sonography is a suitable modality to evaluate bleb characteristics after PGI implantation. Blebs with a double fluid layer are significantly correlated with lower IOP values. Bleb height has an inverse association with IOP, with higher blebs (>2 mm) showing a significantly lower IOP.

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.

Plasma rich in growth factors (PRGF) technology as adjuvant to Ab Externo trabeculectomy

PURPOSE

Plasma rich in growth factors (PRGF) technology creates blood-derived products with growth factors that promote wound healing and regeneration. The goal of this study was to assess the potential role of PRGF products as wound modulators in trabeculectomy. Our premise is that due to PRGF's regenerative and antifibrotic properties, its use in trabeculectomy may produce a more physiological bleb, without altering IOP reduction.

METHODS

A retrospective, longitudinal study was conducted in a Hospital in Portugal. Patients with eyes with open angle glaucoma were included. Trabeculectomy was performed on all patients using PRGF membrane (mPRGF) under the conjunctiva, as adjuvant. Data regarding patients' demographics and number of medications used, was collected. Intraocular pressure (IOP) before surgery, 8 days, 1 month, 3 month, 6 month, 9 month and 1 year after surgery was recorded. Bleb morphology was classified according to Moorfields Bleb Grading System 6 months after surgery.

RESULTS

Nine eyes of 9 patients were enrolled. Mean age was 71 ± 5.1 years old. Six were male. Mean IOP decreased from 24.0 ± 8.8 mmHg pre-surgery to 12.9 ± 2.6 mmHg at one year follow-up. The number of hypotensive drugs (mean ± SD) was 4.3 ± 0.9 preoperatively and 0.8 ± 1.1 at 1-year. Complete success was defined as IOP equal to or less than 21 mm Hg without ocular hypotensive medications and qualified success as IOP equal to or less than 21 mm Hg with medications. Complete success was 66.7% and qualified success was 100% at 1 year follow-up.

CONCLUSION

In our study, trabeculectomy with mPRGF demonstrated both safety and efficacy. Low values of bleb height (1.6 ± 0.8) were recorded. mPRGF could improve wound healing and produce a more well-tolerated, favourable bleb, avoiding antimetabolite complications.

Anterior-Segment Optical Coherence Tomography-Based Evaluation of the Journey of a Bleb in the Early Postoperative Period

Introduction In the early postoperative period following trabeculectomy, monitoring the journey of bleb formation is crucial for assessing surgical success. Anterior-segment optical coherence tomography (AS-OCT) emerges as a powerful tool in this pursuit, offering high-resolution imaging of bleb morphology and dynamics. This study aims to evaluate the internal structure of blebs through their maturation phases using AS-OCT. Methods Fifty-five eyes undergoing trabeculectomy were enrolled in a prospective observational study. Serial AS-OCT examinations were done on day 1, week 1, week 3, and week 6 postoperatively; bleb parameters were calculated and correlated with intraocular pressure (IOP). Results IOP control was seen in 45 eyes six months of post-trabeculectomy. Multiform bleb wall reflectivity (BWR) statistically correlates with the success of trabeculectomy. Blebs were successful if BWR showed no change from day 1 to week 6. BWR remained the same on all follow-ups if week 1 bleb wall thickness (BWT) was less than 129.5 microns with 82.6% sensitivity and 83.3% specificity. The cumulative hazard of change in BWR is estimated to be approximately 5.6%, 15.7%, and 17.9% at week 1, week 3, and week 6 follow-ups, respectively. Conclusions Successful blebs showed consistent BWR from day 1 to week 6 of follow-up. Serial AS-OCT examination for changes in BWR in early stages can be done to predict the fate of bleb. The maximum change in BWR occurs between the week 1 and week 3 follow-up periods requiring close follow-up.

Intravitreal bevacizumab improves trabeculectomy survival at 12 months: the bevacizumab in trabeculectomy study-a randomised clinical trial

AIMS

To evaluate the effect of an intraoperative dose of intravitreal bevacizumab (Avastin) on surgical success following trabeculectomy with mitomycin-C (MMC) over 12 months.

METHODS

A single centre, parallel, double-blinded randomised, placebo-controlled trial recruiting patients requiring trabeculectomy for progressing glaucoma. Patients were randomised to intravitreal bevacizumab or placebo.

MAIN OUTCOME MEASURE

The primary outcome of treatment success was defined by 'complete success' when intraocular pressure (IOP) remained less than a predefined target IOP without the requirement of topical medication, or 'qualified success' where topical medication was required to meet the predefined target IOP threshold. Secondary outcomes included the need for subsequent IOP-lowering interventions, and structural parameters associated with bleb function.

RESULTS

From 131 patients randomised to bevacizumab (n=65) or placebo (n=66), 128 patients completed 12 months of follow-up (98%). At 12 months, success rates were higher in the bevacizumab group (complete success: 94% vs 83%; p=0.015; qualified success: 98% vs 90%; p=0.033). Within the placebo group, the requirement for topical therapy was higher at 6 months (p=0.045) and 12 months (p=0.045), and the requirement for bleb needling was higher at 1 month (p=0.035). Blebs within the bevacizumab group were larger at 1 month (p<0.001) and demonstrated less vessel inflammation (p<0.0001).

CONCLUSION

Bevacizumab given as a single intravitreal dose during trabeculectomy with MMC resulted in improved surgical success as 12 months. Furthermore, bevacizumab was associated with a significant reduction in the need for additional medication or further surgery to achieve target IOP. Bevacizumab was also associated with larger blebs that were less inflamed and required fewer subsequent interventions.

TRIAL REGISTRATION NUMBER

ACTRN12614000375651.

Short-term outcomes of Mitomycin-C augmented phaco-trabeculectomy using subconjunctival injections versus soaked sponges: a randomized controlled trial

OBJECTIVES

To determine whether subconjunctival Mitomycin-C (MMC) injections are as safe and effective as sponge-soaked MMC in phaco-trabeculectomy.

METHODS

This prospective, randomized, interventional study was conducted on consecutive patients with visually significant cataract and an uncontrolled primary open-angle glaucoma. One hundred thirty-nine patients were recruited but 15 were ineligible for analysis. The patients were randomized into a sponge/injection group. All participants received a twin-site phaco-trabeculectomy. They were followed up on days 1, 15, 30, 3 months and 6 months post-operatively. A p-value < 0.05 was considered significant.

INTERVENTIONS

Participants in the sponge group received an augmentation of their phaco-trabeculectomy with sponges soaked in a mixture of 0.04% MMC and 2% preservative-free Lignocaine in a 1:1 ratio, placed in the subconjunctival space for four minutes. Participants in the injection group received the same mixture as a subconjunctival injection, after surgical draping.

RESULTS

There were 62 patients in each group. The groups had no significant differences in their baseline characteristics. The mean IOP at 6 months was significantly lower in the injection group (14.8 ± 3.7 mm Hg) than in the sponge group (17.1 ± 6.4 mm Hg) (p = 0.02). There was no notable difference in the complications or the final post-operative visual outcome but a significantly greater number of patients in the sponge arm required removal of the releasable suture (p = 0.001) and additional anti-glaucoma medications (p = 0.04) at six months post-operatively.

CONCLUSIONS

Subconjunctival MMC achieves a lower IOP with fewer anti-glaucoma medications than sponge-soaked MMC at six months for twin-site phaco-trabeculectomy in primary open-angle glaucoma with no additional risks.

Comparison of Bleb Morphology following PRESERFLO® MicroShunt and Trabeculectomy Using Anterior Segment OCT

Trabeculectomy has traditionally been upheld as the gold standard in glaucoma surgery, but recent advancements, including the PRESERFLO® MicroShunt, have introduced less invasive techniques to mitigate complications and reduce intraocular pressure (IOP). The examination of bleb morphology post-filtering surgery is critical for modulating wound healing and ensuring long-term success. While previous evaluations of PRESERFLO-generated blebs have relied on data from trabeculectomy blebs, the differing surgical techniques used in PRESERFLO and trabeculectomy surgeries suggest potential variations in bleb morphologies. This study conducted a comparative analysis of blebs resulting from PRESERFLO and trabeculectomy procedures. Retrospective descriptive assessments using the Jenaer Bleb Grading System were performed, along with quantitative evaluation using eight-dimensional parameters utilizing anterior segment OCT. We included 93 eyes (57 following PRESERFLO, 36 following trabeculectomy). In the descriptive assessment, PRESERFLO-generated blebs exhibited fewer conjunctival cysts (3.5% vs. 22.2%, p = 0.007) and cavernous changes (10.5% vs. 30.5%, p = 0.021) compared to trabeculectomy. Quantitatively, overall bleb dimensions were comparable (maximal bleb height, width, and length, p > 0.05 for all). However, PRESERFLO blebs displayed a shallower (0.52 ± 0.24 vs. 0.67 ± 0.3 mm, p = 0.017) yet longer (4.12 ± 1.54 vs. 3.23 ± 1.64 mm, p = 0.024) episcleral lake. A thicker bleb wall (1.52 ± 0.46 vs. 1.10 ± 0.37 mm, p < 0.001) along with more posteriorly positioned blebs (distance to limbus = 6.16 ± 1.36 vs. 4.87 ± 1.34 mm, p < 0.001) were observed following PRESERFLO. This study illuminates the nuanced morphological differences between PRESERFLO and trabeculectomy blebs. Understanding these distinctions is vital, empowering clinicians to make informed postoperative decisions and avoid misinterpretation of bleb morphology.

Factors Correlated With Mid-Term Morphology of Functional Blebs Following Implantation of Preserflo MicroShunt Using AS-OCT

Purpose

Evaluating bleb morphology is crucial after glaucoma filtering surgery. Advances in anterior segment optical coherence tomography (AS-OCT) allow for objective assessment. While various parameters differentiate functional from failed blebs, limited information exists regarding variations within functional blebs. This study aimed to identify factors influencing morphology of functional blebs following implantation of Preserflo MicroShunt.

Methods

Eyes with functional blebs after Preserflo were retrospectively included. Age, gender, lens status, preoperative intraocular pressure (pre-IOP) and number of glaucoma medications were documented along with biometric measurements as axial length (AL), white-to-white distance, and anterior chamber depth. Postoperative data included time elapsed since surgery (TaS) and postoperative IOP (post-IOP). Bleb dimensions were measured using AS-OCT including maximal bleb height (MBH), width, length (MBL), bleb wall thickness (BWT), and bleb distance to limbus (DtL) along with dimensions of episcleral lake (maximal height, width [MLW], and length). Linear regression models were applied to correlate these parameters with bleb dimensions.

Results

Included were 50 eyes from 50 patients. Mean IOP decreased from 25.3 ± 10.0 to 11.9 ± 3.0 mm Hg after 278.5 ± 221.9 days after surgery. MBH correlated negatively with age (unstandardized coefficients [uSC] = -0.012) and TaS (uSC = -0.001, P = 0.008 for both). BWT correlated negatively with age (uSC = -0.013, P = 0.02), MBL with AL (uSC = -0.566, P = 0.01) and MLW with pre-IOP (uSC = -0.073, P = 0.02). DtL exhibited a positive correlation with post-IOP (uCS = 0.136, P = 0.02).

Conclusions

Morphology of functional blebs might be influenced by multiple factors such as age, TaS, AL, and pre- and post-IOP.

Translational Relevance

Age, time after surgery, axial length, and preoperative and postoperative IOP could affect the morphology of a functional bleb; hence, these factors should be taken into consideration when making treatment decisions.

Bleb Morphology on Anterior-Segment Optical Coherence Tomography after XEN Gel Stent Implantation

We investigated the internal morphology of filtration blebs after XEN gel stent implantation using anterior segment optical coherence tomography (AS-OCT) and identified factors related to intraocular pressure (IOP) postoperatively. Eighteen eyes of 18 patients who had undergone XEN gel stent implantation were analyzed. Blebs were imaged using Visante OCT (Carl Zeiss Meditec AG, Germany) at 6 months and 1 year after surgery and evaluated for quantitative parameters including bleb height, maximum height of internal cavity, maximum bleb wall thickness, and maximum bleb epithelial thickness. Subjects were classified into two groups according to the presence or absence of a definite internal cavity between the conjunctiva and sclera using AS-OCT imaging. Nine eyes (50%) were assigned to the internal cavity group and 9 (50%) to the uniform group. Postoperative IOP was significantly lower in the internal cavity group than in the uniform group both at 6 months and 1 year after surgery (p = 0.024 and p = 0.040). Postoperative IOP showed statistically significant negative correlations with bleb height and the height of the internal cavity (Spearman correlation coefficient r = -0.518, p = 0.028 and r = -0.453, p = 0.034, respectively). AS-OCT facilitates analysis of bleb morphology after XEN gel stent implantation. A larger height of the internal cavity of the bleb appeared to correlate with lower IOP after XEN implantation.

A Comparative Analysis of Morphology and Dimensions of Functional Blebs following PRESERFLO-Microshunt and XEN-Gel-Stent, a Study Using Anterior Segment OCT

Evaluation of bleb morphology is a vital part of successful filtration glaucoma surgery. The PRESERFLO-MicroShunt (PRESERFLO) and XEN-Gel-Stent (XEN) are drainage devices implanted using different surgical approaches (ab externo and ab interno, respectively), potentially resulting in distinct bleb morphology. Understanding these morphological differences is essential for postoperative care. In this study, we retrospectively examined functioning blebs following PRESERFLO and XEN implantation using high-resolution anterior segment OCT imaging. Qualitative assessment utilizing the Jenaer Bleb Grading System and quantitative assessment measuring 12 parameters representing bleb dimensions were conducted, and the results were compared between the two groups. A total of 80 eyes from 80 patients were included (41 after PRESERFLO, 39 after XEN). Functioning blebs following PRESERFLO exhibited a higher frequency of hyperreflective tenon changes compared to XEN (31.7% vs. 10.3%, respectively, p = 0.02) and a lower frequency of cavernous changes (17.1% vs. 35.9%, p = 0.05). Additionally, PRESERFLO blebs showed a higher frequency of visible episcleral lakes (92.7% vs. 30.8%, p < 0.001). Furthermore, PRESERFLO blebs demonstrated larger height (2.13 ± 0.5 vs. 1.85 ± 0.6 mm, p = 0.03), width (10.31 ± 2.3 vs. 9.1 ± 2.3 mm, p = 0.02), length (9.13 ± 1.8 vs. 8.24 ± 1.9 mm, p = 0.04), posterior location relative to the limbus (6.21 ± 1.2 vs. 5.21 ± 1.8 mm, p = 0.005), and a thicker bleb wall (1.60 ± 0.5 vs. 1.1 ± 0.4 mm, p = 0.004). Functioning blebs following PRESERFLO and XEN displayed morphological distinctions, likely attributed to variations in surgical techniques (ab externo vs. ab interno) and stent dimensions. These morphological differences should be taken into consideration when evaluating blebs, as they could impact assessments of bleb functionality and influence decisions regarding postoperative interventions.

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.

Mitomycin C-loaded PTMC15-F127-PTMC15 hydrogel maintained better bleb function after filtering glaucoma surgery in monkeys with intraocular hypertension

There is an unmet need for a safer and more effective approach for antimetabolite application to prevent bleb fibrosis after glaucoma filtering surgery. Here, we utilized our previously developed thermosensitive sustained-release agent, mitomycin C-loaded poly(trimethylene carbonate)15-F127-poly(trimethylene carbonate)15 (MMC-hydrogel), aiming to further evaluate the efficacy and safety of MMC-hydrogel in high intraocular pressure (IOP) primate eyes. Twelve primate eyes after high IOP induction were randomly divided into three groups, which respectively received phosphate-buffered saline (PBS)-hydrogel, MMC-hydrogel, and MMC treatment during trabeculectomy. IOP and bleb volume were measured using a Tonopen and anterior segment optical coherence tomography over 28 days. At the end of the experiment, all experimental primate eyes were enucleated. Histopathology and immunohistochemistry were performed to reveal myofibroblast cells and collagen deposition of filtering blebs. The MMC-hydrogel group had satisfactory IOP control (9.25 ± 4.80 mmHg) and maintained well-functioning blebs for a longer time. Fibrosis and scarring were significantly alleviated in this MMC-hydrogel group. There was no obvious toxicity to ocular surfaces or intraocular structures. Taken together, these data suggest that PTMC15-F127-PTMC15-loaded MMC-hydrogel plays a role in functional maintenance and scarring inhibition, showing high efficacy in reducing post-filtering surgery bleb fibrosis. This MMC-hydrogel may offer a new solution for filtering bleb management after glaucoma surgery.

[Bleb morphology using optical coherence tomography : After primary implantation of XEN gel stent and open conjunctival revision]

BACKGROUND

The implantation of a XEN gel stent is an innovative method for filtration surgery using an ab interno approach. The morphological evaluation of the resulting bleb is decisive for surgical success. Bleb revision is frequently needed after XEN implantation and might affect the bleb morphology. Aim of this study was to examine bleb morphology using anterior segment OCT (AS-OCT) and analyze the morphological differences of blebs after primary XEN implantation and after bleb revision.

MATERIAL AND METHODS

Included were eyes that underwent XEN implantation (Pr-X) or bleb revision after XEN (Re‑X group). An AS-OCT of blebs was performed and images were classified using a novel classification system (the Jenaer bleb grading system, JBGS). Frequency of different tomographic patterns (M) and their correlation with intraocular pressure (IOP) were analyzed.

RESULTS AND DISCUSSION

A total of 69 eyes (40 in the Pr‑X and 29 in the Re‑X groups) were included. At the conjunctival level, the most common M in both groups was subconjunctival spaces (M-C2) followed by intraconjunctival cysts (C1) and no conjunctival changes (C0). No differences of frequencies between the two groups or of IOP between the three Ms were seen. At the tenon level, the most commonly seen Ms in the Pr‑X group were hyporeflective and cavernous changes (M-T2, T3) followed by no changes (M0) and hyperflective changes (T1). In the Re‑X group, the M‑T1 and T2 were most commonly seen followed by T3 and T0. The M‑T2 and T3 in the Pr‑X group and the M‑T1 and T2 in the Re‑X group correlated with lower IOP. An episcleral lake (M-ES1) was seen significantly less frequently in the Pr‑X group compared with Re‑X group where it correlated with lower IOP CONCLUSION: The hyperreflective changes at the tenon level and the presence of an episcleral lake were seen more frequently following bleb revision compared with primary XEN implantation and correlated with lower IOP. The interpretation of bleb morphology using AS-OCT should only be done considering the surgical approach used.

Filtering Bleb Size in the Early Postoperative Period Affects the Long-term Surgical Outcome after Trabeculectomy

PURPOSE

To investigate whether postoperative filtering bleb size affects the surgical outcome after trabeculectomy.

METHODS

In this study, we retrospectively reviewed 145 medically uncontrolled glaucoma patients with intraocular pressure (IOP) values >21 mmHg before surgery and data from ≥2 years of follow-up. Postoperative IOP, filtering bleb size including extent and height, and other clinical factors were measured after trabeculectomy. We divided bleb extent into quadrants and bleb height by 0.5 intervals of corneal thickness. The main outcome measure was surgical success. We confirmed complete success when the IOP was ≤21 mmHg and decreased by >20% from baseline without medication or additional procedures. Qualified success used the same criteria but allowed for medication or additional procedures. Cases with reoperation or two consecutive IOP measurements <6 mmHg were considered failures.

RESULTS

A total of 145 eyes of 145 patients was included. The average observation period was 30.8 ± 10.9 months. During multivariate Cox regression analysis, a larger extent of filtering bleb revealed significantly low hazard ratios in both complete and surgical success (0.509 and 0.494, respectively); however, there was no significant relationship between bleb height and surgical outcome.

CONCLUSIONS

The extent of the filtering bleb was associated with surgical outcomes of trabeculectomy in glaucoma patients.

Novel Bleb Classification Following Ab Interno Implantation of Gel-Stent Using Anterior Segment Optical Coherence Tomography

PRCIS

A novel qualitative tomographical classification for bleb after implantation of XEN-Gel-Stent using ab interno approach is presented. Association of anatomic patterns to intraocular pressure (IOP) and success rates (SR) illustrates that anterior segment optical coherence tomography can be useful tool in clinical guidance.

PURPOSE

To present a novel classification of bleb resulting from ab interno implantation of XEN-Gel-Stent and report association of tomographical patterns with IOP and SR.

MATERIALS AND METHODS

A cross-sectional 1-armed study of patients receiving XEN-Gel-Stent. Tomographical changes in the bleb area were studied using swept-source optical coherence tomography in an early (d 29-90 postsurgery) and late (starting from d 91 postsurgery) phase. Frequency of patterns and their association with IOP and SR (defined as IOP<18 mmHg without medications) were studied.

RESULTS

One hundred eleven examinations of 49 blebs (49 patients) were included. Three tomographical patterns at conjunctival, 4 at tenons capsule, and 2 at episcleral level were characterized. Most frequent conjunctival pattern was subconjunctival spaces (56.3% and 53.2% in the early and late phase, respectively) and associated with lower IOP (13.0±6.0 mmHg) and higher SR (89%) but only in the early phase compared with other conjunctival patterns ( P <0.05). At tenons capsule level, the hyporeflective pattern was most frequent (50% and 51.9% in early and late phase) followed by the cavernous pattern. Both patterns associated with lower IOP and higher SR compared with hyper-reflective or loss of tenon changes ( P <0.005). Most blebs showed no episcleral lake (87.5% and 89.9% in early and late phase). No difference of IOP and SR was noted compared with those showing an episcleral lake.

CONCLUSION

A practical and clinically relevant novel classification system is proposed to tomographically describe and classify blebs after implantation of XEN-Gel-Stent. Certain patterns were associated with lower IOP and higher SR.

Inhibitory Effects of 3',4'-Dihydroxyflavonol in a Mouse Model of Glaucoma Filtration Surgery and TGFβ1-Induced Responses in Human Tenon's Fibroblasts

Purpose

Cytotoxic agents such as mitomycin C (MMC) are part of the mainstay treatment for limiting subconjunctival scarring following glaucoma filtration surgery (GFS). However, a safer antifibrotic therapy is clinically needed. The anti-scarring properties of 3′,4′-dihydroxyflavonol (DiOHF) were evaluated in a mouse model of GFS and in cultured human Tenon's fibroblasts (HTFs).

Methods

GFS was performed in C57BL/6 mice receiving daily intraperitoneal injections of DiOHF or vehicle or a single intraoperative injection of MMC. Eyes were harvested on day 14 for assessment of collagen deposition, expression of alpha-smooth muscle actin (α-SMA), cluster of differentiation 31 (CD31), and 4-hydroxy-2-nonenal (4HNE) in the conjunctiva/Tenon's layer. The inhibitory effects of DiOHF on transforming growth factor β (TGFβ)-induced responses were also assessed in HTFs.

Results

Treatment with DiOHF demonstrated a reduction in collagen deposition at the GFS site compared to vehicle-treated mice. The degree of 4HNE-positive fluorescence was significantly reduced in DiOHF-treated eyes compared to the other groups, indicating a decrease in oxidative stress. A reduction in expression of α-SMA and CD31 was seen in DiOHF-treated conjunctiva compared to those treated with vehicle. Concordant results were demonstrated in cultured HTFs in vitro. Furthermore, treatment of cultured HTFs with DiOHF also displayed a reduction in the proliferation, migration, and contractility of HTFs.

Conclusions

Treatment with DiOHF reduces scarring and angiogenesis in the conjunctiva of mice with GFS at a level comparable to MMC. The reduction in oxidative stress suggests that DiOHF may suppress scarring via different mechanisms from MMC.

Translational Relevance

DiOHF may be a safer and superior wound modulating agent than conventional antifibrotic therapy in GFS.

The Norwich trabeculectomy study: risk factor analysis for the development of adverse, thin cystic blebs

PURPOSE

To investigate potential risk factors, particularly antimetabolite choice, with regard to the development of adverse bleb morphology in eyes that had undergone trabeculectomy surgery.

METHODS

A single-centre, observational cohort study of 631 consecutive eyes, which had undergone trabeculectomy over an 11-year period. For each case, bleb morphology was recorded at 2 years, and its association with the per-operative antimetabolite as well as potential confounding risk factors was analysed using univariate (unadjusted) and multivariate (adjusted) logistical regression analyses to identify those that could contribute to the development of adverse blebs. A standard protocol for 5-fluorouracil and mitomycin-C utilization was employed in the majority of cases.

RESULTS

When 5-fluorouracil was used (n = 257), 24% of patients formed cystic or partially cystic blebs, whereas with mitomycin-C (n = 299), only 12% formed such adverse blebs, the difference being statistically significant (OR = 3.54, p = 0.002 unadjusted; OR = 7.49, p = 0.00 adjusted). Of the other potential confounding factors, care within the private sector (OR = 0.30 p = 0.02) and a history of previous ocular surgery involving a conjunctival incision were identified as potential risk factors for the formation of adverse cystic blebs (OR = 0.28, p = 0.02).

CONCLUSIONS

Modern use of mitomycin-C appeared to be better than 5-fluorouracil as an adjunctive antimetabolite used at the time of trabeculectomy, with respect to the development of preferable final bleb morphology. The only potential preoperative risk factors found to be significant with respect to adverse cystic bleb development were care in the private health sector and previous ocular surgery involving a conjunctival incision.

Anterior Segment-Optical Coherence Tomography Bleb Morphology Comparison in Minimally Invasive Glaucoma Surgery: XEN Gel Stent vs. PreserFlo MicroShunt

Background: The purpose of this study is to compare the morphology of six-month follow-up blebs created by a subconjunctival glaucoma surgical device (XEN45) to those created by a PreserFlo MicroShunt with a sub-Tenon insertion, utilizing AS-OCT. Methods: A retrospective study of 29 eyes who underwent XEN45 implantation and 29 eyes who underwent PreserFlo MicroShunt implantation. The patients were analyzed at 24 h, 1 week, 1 month, 3 months and 6 months. At each visit, the maturation and morphological alterations of the blebs were observed, as well as connections with the IOP. Results: In both groups, IOP showed significant reduction at all follow ups (p < 0.0001). In XEN group, the most common bleb morphology in the immediate postoperative was the subconjuntival separation type (42%) followed by the uniform type (34%), with a trend inversion at 6 month follow up (51% of uniform type). On the contrary, the most common morphology after PreserFlo was the multiple internal layer (55%), which showed a tendency to reduce over time and was substituted by the microcystic multiform, whose percentage increased over time (17% at day 1 vs. 44% at month 6). Uniform appearance was associated by the posterior episcleral fluid (PEF) lake presence. Both horizontal and vertical diameters significantly increased over time. Conclusion: XEN and PreserFlo implantation resulted in the production of diffuse blebs with different characteristics, which may influence IOP lowering capacity and bleb revisions necessity over time.

Ologen implant versus mitomycin C in combined trabeculectomy and phacoemulsification

Purpose:

To comparatively evaluate in Indian eyes with coexisting cataract and primary open-angle glaucoma the outcome of mitomycin C (MMC) and Ologen implant as adjunctives in combined phacoemulsification with trabeculectomy.

Methods:

Eyes with primary open-angle glaucoma that underwent trabeculectomy and phacoemulsification with IOL implantation with either MMC application or Ologen implant between June 2019 and February 2020 were followed up for 12 months. Thirty-four eyes of 34 participants were studied. The primary outcome was intraocular pressure (IOP), and the secondary outcomes were the number of ocular hypotensives, best distance visual acuity (BDVA), and bleb morphology.

Results:

In 16 eyes treated with MMC and 18 eyes treated with Ologen implant, it was observed that the mean postoperative IOP (14.62 ± 2.89 mm Hg with MMC and 14.56 ± 4.14 mm Hg with Ologen implant) was not significantly different in both groups (P = 0.47). Number of ocular hypotensives and BDVA were also comparable between the two groups. However, bleb morphology was better with Ologen implantation. One eye in the MMC group developed hypotony which was conservatively managed

Conclusion:

MMC and Ologen are both effective adjunctives in combined phaco-trabeculectomy. However, the Ologen implant provides better bleb health and safety.

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.

Anterior-segment optical coherence tomography of filtering blebs in the early postoperative period of ab externo SIBS microshunt implantation with mitomycin C: Morphological analysis and correlation with intraocular pressure reduction

PURPOSE

To analyse the morphological evolution of filtering blebs with anterior-segment OCT (AS-OCT) and its correlation with intraocular pressure after ab externo SIBS microshunt implantation with mitomycin C (MMC) during a 3-month follow-up period.

METHODS

Twenty-eight filtering blebs of 28 patients with open-angle glaucoma were measured horizontally and vertically in the sub-Tenon space with AS-OCT after ab externo SIBS microshunt implantation with MMC. The intraocular pressure (IOP) was monitored simultaneously at each visit. Maturation of and morphological changes in the blebs and correlations with the IOP were recorded.

RESULTS

The average median preoperative IOP of 20.7 (range, 12-30) mmHg decreased to 8.5 (range, 4-17), 8.9 (range, 5-17), 10.4 (range, 8-16) and 10.9 (range, 9-15) mmHg at 24 hr, 1 week, 1 month and 3 months, respectively (p < 0.001). A multiform morphology on AS-OCT prevailed at all time points, with a 3.5% rate of a uniform bleb morphology at the first week. The horizontal and vertical diameters of the blebs increased from baseline to the third month. The horizontal expansion (406 ± 127 μm on day 7, p = 0.04, 712 ± 211 μm on day 30, p = 0.02 and 952 ± 218 μm on day 90, p < 0.001) was greater than the vertical expansion (16 ± 18 μm, p = 0.3 on day 1, 63 ± 27 μm, p = 0.02 on day 30 and 137 ± 34 μm, p < 0.001 on day 90) without correlation with the IOP (r = -0.3, p = 0.2).

CONCLUSION

Anterior-segment OCT (AS-OCT) of the filtering blebs formed after ab externo SIBS microshunt implantation showed progressive horizontal and vertical expansion of the blebs in the sub-Tenon space, with a significant peak at the first month not significantly correlated with the decrease in the IOP.

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.

Advances and Current Clinical Applications of Anterior Segment Optical Coherence Tomography Angiography

Optical coherence tomography angiography (OCTA) is the most relevant evolution based on optical coherence tomography (OCT). OCTA can present ocular vasculature, show detailed morphology for assessment, and quantify vessel parameters without intravenous dye agent. Research on the anterior segment OCTA (AS-OCTA) is only in its initial phase, and its advances in clinical diagnosis and treatment efficacy evaluations require a detailed comparison to traditional imaging methods. In this review of AS-OCTA, we summarize its technical features, imaging advances, current clinical applications in various eye diseases, as well as its limitations and potential future directions. AS-OCTA offers potential advantages in ophthalmic imaging, and with further development it could become a common tool in the near future.

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.

Assessing safety and success after using bevacizumab, 5-fluorouracil or placebo in primary trabeculectomy. A Prospective Randomized placebo controlled 1-Year Follow-up Study

PURPOSE

The aim of this study was to determine whether glaucoma patients after trabeculectomy could benefit more from subconjunctival injections of bevacizumab than 5-FU or placebo.

METHODS AND RESULTS

Fifty-one eyes of 51 patients were recruited for primary MMC (0.2mg/ml for 1 min) augmented trabeculectomy. 17 patients were randomly assigned to receive 1.25mg (0.05ml) of bevacizumab augmentation, 21 patients were assigned to receive 0.1ml of 50mg/ml 5-FU and 13 patients were assigned to a control group receiving a normal saline injection as a placebo. Initial recruitment included 58 patients, but seven patients had to be excluded from the study for various reasons. Postoperative follow up of IOP and bleb characteristics was carried out at 1 day, 1 week, 3 weeks, 6 weeks, 6 months and 1 year after surgery. All analyses where carried out by two masked clinicians. IOP reduction was statistically significant (P < 0.05) across all three groups between baseline visit and final 1-year postoperative visit. There was no significant difference of the final average IOP values between the three groups. Bleb evaluation was made using the Moorfields bleb grading system (MBGS) after 1 year follow up. Central bleb area was statistically greater in the Bevacizumab group when compared with the 5-FU group but not with the placebo group. The vascularity of the central bleb was significantly different between the groups with the Bevacizumab group showing the least vascularity. Vascularity of the peripheral bleb was also decreased in the Bevacizumab group when compared with the placebo group but not with the 5-FU group.

CONCLUSION

The 12-month IOP results showed no significant differences between the groups of patients after Bevacizumab, 5-FU or placebo to augment primary MMC enhanced trabeculectomy. However, by the analysis of bleb morphology there was a significant difference in terms of central bleb area and vascularity.

Comparison of bleb morphology by anterior segment optical coherence tomography and clinical outcome after phacotrabeculectomy with mitomycin C or Ologen implant

Purpose:

To compare the bleb morphology by Anterior Segment Optical Coherence Tomography (ASOCT) and clinical outcome after Phacotrabeculectomy with either mitomycin C or Ologen implant.

Methods:

In a prospective interventional active controlled study, 93 patients aged 18 years and above underwent phacotrabeculectomy with either mitomycin C (53 eyes) or ologen implant (40 eyes), followed up for 12 months. The primary outcome measure was to note the evolution of bleb morphology by ASOCT in the two groups over 12 months. Secondary outcome measures were mean IOP, reduction in the need for anti-glaucoma medications, and complications seen in the two groups.

Results:

All parameters in the two groups were comparable preoperatively (P>0.05). Best corrected visual acuity at 12 months was 0.38±0.27 in mitomycin group and 0.31±0.23 in ologen group (P=0.151). Post-operative IOP at 12 months was 14.09±3.1mmHg (95%CI 13.22-14.97) in mitomycin group, and 13.25±2.5 mmHg (95%CI 12.40-14.30) in ologen group (P=0.254).The mean number of medications was 0.36±0.68 in mitomycin group and 0.38+/-0.70 in ologen group at 12 months (P=0.91). Overall success was achieved in 98.1 % of patients in mitomycin group and 90 % of patients in ologen group at 12 months. No major sight-threatening complications were noted in any group. AS-OCT imaging at 12 months showed multiform reflectivity with multiple large cystic spaces in both groups, with good IOP control.

Conclusion:

Phacotrabeculectomy using Mitomycin C and Ologen implant resulted in similar morphologic and functioning blebs at one year with comparable efficacy in controlling intraocular pressure.

Intraocular Pressure-Lowering Effects of Trabeculectomy Versus MicroShunt Insertion in Rabbit Eyes

Purpose

To compare the surgical results of PRESERFLO MicroShunt (MicroShunt) insertion and trabeculectomy in rabbit eyes.

Methods

Trabeculectomy or MicroShunt insertion was performed on the eyes of Japanese white rabbits. Intraocular pressure (IOP) was measured on conscious rabbits using a rebound tonometer for up to 12 weeks after surgery. Filtering bleb appearance was evaluated. Scarring in the filtering bleb was assessed by immunohistochemical analyses. The change in mRNA expression in the conjunctiva was evaluated using RNA sequence analyses.

Results

The preoperative IOP of the operative eye did not differ significantly between trabeculectomy (11.6 ± 1.0 mmHg, n = 10) and MicroShunt insertion (12.6 ± 1.3 mmHg, n = 10). In both groups, the IOP of the operative eye was significantly lower than that of the contralateral eye at one day postoperatively, which continued until 12 weeks after surgery. The peak differences in IOP were −8.4 ± 3.0 (trabeculectomy) and −8.1 ± 2.1 mmHg (MicroShunt) at two weeks after surgery; no significant differences were observed in IOP reduction between the groups. Appearance and immunohistochemical analyses of the filtering bleb showed no significant difference between the groups. Moreover, RNA sequence analysis results showed no difference between the groups in mRNA expression fluctuations.

Conclusions

Postoperative IOP, bleb appearance, and immunohistochemical analysis results were similar in the trabeculectomy and MicroShunt groups, indicating that MicroShunt insertion is as effective as trabeculectomy in lowering IOP.

Translational Relevance

Comparison of surgical procedures using animal models has made it possible to predict clinical efficacy and safety.

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.

Evaluation of Successful and Failed Filtering Blebs after Trabeculectomy Using Anterior Segment Optical Coherence Tomography

Purpose:

To evaluate filtering bleb characteristics using anterior segment optical coherence tomography (AS-OCT) and analyze correlations between these parameters and intraocular pressure (IOP).

Methods:

The study included 54 eyes of 43 patients who underwent trabeculectomy with mitomycin-C. The patients were divided into two groups based on mean postoperative IOP. The criterion for surgical success was mean unmedicated postoperative IOP ≤18 mmHg. Patients with IOP values >18 mmHg were prescribed anti-glaucoma drops and classified as a surgical failure. All patients underwent AS-OCT, and maximum bleb height, maximum bleb wall thickness, and maximum fluid-filled cavity height were measured. AS-OCT bleb parameters were compared between the successful and failed groups.

Results:

Of the 54 eyes, 37 (68.5%) were in the successful group, and 17 (31.5%) were in the failed group. Mean preoperative IOP values in the successful and failed groups were 26.9 ± 6.5 mmHg and 22.9 ± 4.9 mmHg, preoperatively, versus postoperative values of 13.3 ± 2.1 mmHg and 22.8 ± 2.8 mmHg, respectively. Mean postoperative follow-up time was 17.4 ± 9.5 months in the successful group and 19.1 ± 10.1 months in the failed group (P = 0.22). In the successful and failed groups, mean bleb height was 1473.7 ± 150.6 μm and 1165.4 ± 217 μm (P < 0.001), bleb wall thickness was 670.5 ± 119.9 μm and 538.8 ± 144.3 μm (P = 0.001), and fluid-filled cavity height was 736.5 ± 196.8 μm versus 532.5 ± 226.2 μm (P = 0.001), respectively.

Conclusions:

The results of this study showed that higher AS-OCT values for bleb height, wall thickness, and fluid-filled cavity height were associated with greater functional success. These parameters may be helpful in determining bleb functionality.

The significance of ultrasound biomicroscopy in the objective assessment of post-trabeculectomy bleb success

PURPOSE

To compare clinical characteristics and ultrasound biomicroscopy (UBM) measurements of cases with functional and non-functional blebs, and to identify potential risk factors capable of affecting UBM parameters.

METHODS

Thirty-one patients aged 40-79 were included. Following trabeculectomy, cases were divided into two groups as those with functional bleb (Group 1, n = 20) and those with non-functional bleb (Group 2, n = 11). UBM was performed.

RESULTS

In Group 1 compared to Group 2, lower postoperative intraocular pressure (IOP) (12.1 ± 1.7 vs 27.2 ± 3.2 mmHg, p < 0.001), greater bleb height (1.0 ± 0.2 vs 0.5 ± 0.3 mm, p < 0.001), greater scleral route visibility [16/20 (80%) vs 4/11 (36.4%), p = 0.023] and lower bleb reflectivity (1.8 ± 0.2 vs 2.4 ± 0.4, p = 0.015) were observed. In Group 1, as postoperative IOP decreased, bleb height and scleral route visibility increased (r = -0.387, p = 0.029 for bleb height; r = -0.374, p = 0.033 for scleral route), and bleb reflectivity decreased (r = 0.359, p = 0.042). In Group 1, as duration of preoperative antiglaucoma drug use increased, bleb reflectivity increased (r = 0.348, p = 0.046). Preoperative IOP and number of preoperative antiglaucoma drug use had no effect on UBM parameters in groups (p > 0.05).

CONCLUSION

UBM is useful in assessing bleb success. Lower bleb reflectivity, greater bleb height and greater scleral route visibility indicate that the bleb is functional. To the best of our knowledge, this is the first study investigating effects of preoperative IOP, number and duration of preoperative antiglaucoma drug use on UBM parameters. In cases with functional bleb, duration of preoperative drug use affects only bleb reflectivity, while postoperative IOP affects bleb height, scleral route visibility and bleb reflectivity.

Comparison of the Efficacy and Safety of Trabeculectomy with Mitomycin C According to Concentration: A Prospective Randomized Clinical Trial

(1) Background: Mitomycin C (MMC) is commonly used during trabeculectomy. However, there is no consensus on which concentration should be used. We aimed to compare the efficacy and safety of 0.2 mg/mL and 0.4 mg/mL of MMC in eyes undergoing trabeculectomy. (2) Methods: Thirty-six eyes (36 glaucoma patients) were randomized to undergo a trabeculectomy with 0.2 mg/mL or 0.4 mg/mL of MMC. The success rate was evaluated according to three criteria: (A) intraocular pressure (IOP) ≤ 18 mmHg and IOP reduction ≥ 20%; (B) IOP ≤ 15 mmHg and IOP reduction ≥ 25%; (C) IOP ≤ 12 mmHg and IOP reduction ≥ 30%. Cox’s proportional hazard model was used to identify the predictive factors for failure. Immunohistochemical procedures for matrix metalloproteinase (MMP) were performed on Tenon’s tissue. Bleb morphology was evaluated. Safety was assessed based on the incidence of complications. (3) Results: Of the 36 eyes, 19 underwent trabeculectomy with 0.2 mg/mL of MMC and 17 with 0.4 mg/mL. The success rates were 75%, 67%, and 47% at 6 months for criteria A, B, and C, respectively. There were no significant differences between the two groups. High MMP-9 staining and low preoperative IOP were associated with failure (hazard ratio (HR), 5.556; p = 0.033, and HR, 0.936; p = 0.033). Complications included hypotony in two eyes (6%), hyphema in one eye (3%), and choroidal detachment in one eye (3%). (4) Conclusions: Trabeculectomy with 0.2 mg/mL and 0.4 mg/mL of MMC showed similar IOP-control effects to those recorded in previous studies, along with a low rate of complications. There was no significant difference in efficacy or safety between the 0.2 mg/mL and 0.4 mg/mL MMC groups.

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.

Predictive Value of Bleb Vascularity after Mitomycin C Augmented Trabeculectomy

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

Stab incision mitomycin C-assisted rapid trabeculectomy: A 'SMART' trabeculectomy alternative

The aim of the present study was to introduce a new modified trabeculectomy technique, stab incision mitomycin C (MMC)-assisted rapid trabeculectomy (SMART), which requires less surgical time and tissue manipulation. A total of 41 eyes with indication for trabeculectomy underwent glaucoma surgery with the SMART technique; superior subconjunctival injection of 0.005 mg MMC mixed with 0.1 ml lidocaine, followed by small, fornix base conjunctival opening. A stab incision was made to enter the anterior chamber 1.5 mm post-limbus using a 2.4 mm cataract knife. Double 0.75 mm punch and peripheral iridectomy were performed. A releasable suture was placed in the scleral opening, and matrix sutures to close conjunctiva. The preoperative mean intraocular pressure (IOP) was 23.8 mmHg, with a mean number of medications of 3.3. The mean follow-up duration was 27.6 months, with a range of 12-46 months. A year post-surgery, the mean IOP was 11 mmHg, with a mean number of medications of 0.7, corresponding to a reduction of 12.8 mmHg in IOP and 2.6 in the number of medications. During follow-up, additional 5-fluorouracil injections were administered when needed. In conclusion, SMART with wound modulation appears to be a safe and quick alternative to classic trabeculectomy. Few minor and no major complications were observed during the first 2.5 years of follow-up, with all eyes maintaining an IOP <15 mmHg.

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.

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.

The control of conjunctival fibrosis as a paradigm for the prevention of ocular fibrosis-related blindness. "Fibrosis has many friends"

The processes involved in ocular fibrosis after disease or ocular tissue injury, including surgery play an important part in the development or failure of treatment of most blinding diseases. Ocular fibrosis is one of the biggest areas of unmet need in ophthalmology. Effective anti-scarring therapies could potentially revolutionise the management of many diseases like glaucoma worldwide. The response of a quiescent or activated conjunctiva to glaucoma surgery and aqueous flow with different stimulatory components and the response to different interventions and future therapeutics is a paradigm for scarring prevention in other parts of the eye and orbit. Evolution in our understanding of molecular and cellular mechanisms in ocular fibrosis is leading to the introduction of new and re-purposed therapeutic agents, targeting a wide range of key processes. This review provides current and futures perspectives on different approaches to conjunctival fibrosis following glaucoma surgery and highlights the challenges faced in implementing these therapies with maximal effect and minimal side effects.

A Comparison of Subconjunctival Wound Healing between Different Methods of Dissecting Subconjunctival Tissues

OBJECTIVE

To compare different methods for dissecting subconjunctival tissues by developing subconjunctival wound healing models.

METHODS

New Zealand white rabbits were separated into 3 groups based on the method by which the rabbit subconjunctival wound healing model was generated: subconjunctival tissues were dissected episclerally (EPI) or subepithelially (SUB), with a corresponding blank control (CON). All the cases in the experimental groups were surgically prepared with conjunctival flaps, and they were sacrificed on the third postoperative day. At the surgical sites, the protein levels of hypoxia-inducible factor-1 (HIF-1)-α, vascular endothelial growth factor (VEGF)-A, and matrix metalloproteinase (MMP)-2 were detected by Western blot, morphological vascularity was measured by Adobe Photoshop, and subconjunctival fibrosis was assessed by histology.

RESULTS

Compared with the CON group, both the EPI and SUB groups showed significantly upregulated protein levels of HIF-1α, VEGF-A, and MMP-2. In addition, the protein levels of HIF-1α, VEGF-A, and MMP-2 were higher in the EPI group than in the SUB group. Morphological vascularity was significantly elevated in the EPI group compared with the SUB and CON groups. Collagen content was markedly increased in the EPI group compared with the SUB and CON groups.

CONCLUSIONS

Dissecting subconjunctival tissues subepithelially inhibits subconjunctival fibrosis, which may be instructive in tenonectomy in filtration surgery.

Morphological analysis of functional filtering blebs with anterior segment optical coherence tomography: A short-term prediction for success of trabeculectomy

PURPOSE

The aim of the study was to analyze morphological parameters of apparently functional filtering blebs with anterior segment optical coherence tomography at 1 month post trabeculectomy and to correlate these parameters with intraocular pressure at 6 months of follow-up to predict the short-term success of trabeculectomy.

METHODS

In this cross-sectional, descriptive study, apparently functional blebs were evaluated using anterior segment optical coherence tomography with crossline scans after 1 month of trabeculectomy.

RESULTS

A total of 55 eyes of 55 cases with mean age 49.29 ± 13.72 years were included in the study. On anterior segment optical coherence tomography examination, the mean bleb height and mean bleb wall thickness, subconjunctival fluid space, and scleral flap thickness were 1.45 ± 0.39 mm, 0.63 ± 0.25 mm, 0.64 ± 0.26 mm, and 0.45 ± 0.068 mm, respectively. There was statistically significant negative correlation between intraocular pressure at 1 month and bleb height (r = -0.25, p = 0.05). There was statistically significant negative correlation between extent of cavity and intraocular pressure at 6 months (r = -0.318, p = 0.018). Bleb height showed significant negative correlation with supra-scleral space (r = -0.31, p = 0.02). Multi reflective bleb walls showed statistically significant increased chances of successful functioning blebs at 6 months as compared to uniform wall reflectivity (p = 0.00).Bleb function was successful in 37 (67.3%) and unsuccessful in 18 (32.7%) in short term of 6 months of follow-up.

CONCLUSION

Bleb walls with multiform wall reflectivity on anterior segment optical coherence tomography at 1 month post trabeculectomy show increased chances of success of functioning filtering bleb at 6 months. Bleb wall characteristics on anterior segment optical coherence tomography at 1 month can predict the short-term success of blebs at 6 months.

Phacotrabeculectomy using collagen matrix implant (Ologen® ) versus mitomycin C: a prospective randomized controlled trial

PURPOSE

To compare the efficacy and safety of collagen matrix implant (Ologen^® ; OLO) with mitomycin C (MMC) in phacotrabeculectomy.

METHODS

Prospective, single-centre, nonblinded, randomized controlled trial. A total of 53 eyes of 45 patients were enrolled in the study protocol with 27 eyes randomly assigned to OLO and 26 to MMC. The follow-up was 12 months. The primary outcome measure was mean change from baseline intraocular pressure (IOP) in both groups after 12 months. The secondary outcome measures were cumulative success rates at 12 months with Kaplan-Meier analysis, change in number of medications, change in best corrected visual acuity (BCVA), and bleb morphology assessed using Moorfields Bleb Grading System and anterior segment swept-source optical coherence tomography.

RESULTS

The mean IOP decreased from 26.4 ± 6.1 mmHg to 13.7 ± 3.8 in the OLO group and from 23.4 ± 3.6 mmHg to 13.3 ± 2.8 in the MMC group at 1 year without significant intergroup differences. At 1 year, the overall success rates were 92.6% and 92.3% in the OLO and MMC groups, respectively. There were no significant differences in the overall success rates, BCVA, number of medications, morphology of the filtering blebs and rate of complications at the end of the follow-up.

CONCLUSION

Ologen (OLO) provides similar surgical outcomes in phacotrabeculectomy compared with adjunctive MMC. It may be a new, safe and effective alternative to MMC for combined phacoemulsification and trabeculectomy surgery.

Optical Coherence Tomography Angiography Evaluation of Conjunctival Vessels During Filtering Surgery

Purpose

To evaluate the changes in conjunctival vascularization with optical coherence tomography angiography (OCT-A) before and after filtering surgery and to correlate these results with filtering surgery success.

Methods

We evaluated 20 blebs of 20 patients after a first-time trabeculectomy. Conjunctival vascularization was quantified using ImageJ software. Eyes were classified into two groups according to the preoperative conjunctival vessel density: hypovascularized conjunctiva (HypoV; 10 eyes) and hypervascularized conjunctiva (HyperV; 10 eyes). The density of intraepithelial microcysts (0 to 3) was also analyzed.

Results

There were significantly more needling procedures in the HyperV group, with 70% of the eyes undergoing needling during follow-up compared to 20% in the HypoV group (P = 0.012). In the HyperV group, 50% of the eyes required IOP-lowering eyedrops after surgery, compared to 10% in the HypoV group (P = 0.029). HypoV showed significantly more intraepithelial microcysts than did HyperV at 1 week (1.1 vs. 0.4, P = 0.0215), 1 month (2.2 vs. 0.4, P = 0.0003), and 6 months postoperatively (2.0 vs. 0.7, P = 0.0068). A statistically significant correlation was found between preoperative conjunctival vascular density and mean IOP at 1 week (r = 0.483, P = 0.038), 1 month (r = 0.714, P = 0.001), and 6 months postoperatively (r = 0.471, P = 0.043). There was no statistically significant correlation between the preoperative conjunctival vascularization density and the eyedrop-year rate (r = 0.036, P = 0.8704) or the preservative-year rate (r = 0.1444, P = 0.5107).

Conclusions

Poor conjunctival vascularization was associated with lower IOP and a higher number of intraepithelial microcysts evaluated with OCT-A. OCT-A provides a simple, noninvasive, and reproducible method to analyze and quantify bleb vessels before and after filtering surgery.

Translational Relevance

Several studies have demonstrated that highly vascularized blebs might be associated with a higher risk of failure. OCT-A may provide a dye-free, noncontact method for monitoring conjunctival vascularization after filtering surgery.

Bimatoprost loaded nanovesicular long-acting sub-conjunctival in-situ gelling implant: In vitro and in vivo evaluation

Primary treatment for glaucoma relies on chronic instillation (daily) of intraocular pressure (IOP) lowering eye drops. Present study tends to develop and assess a novel sustained release bimatoprost loaded nanovesicular (BMT-NV) - thermosensitive in-situ gelling implant (BMT-NV-GEL-IM), for subconjunctival delivery. BMT-NVs developed using novel composition and method of preparation, (IPA/700/DEL/2014) and industrially viable methodology were characterized and evaluated comprehensively for ocular suitability. Their incorporation into an in-situ gelling formula was safe (in vitro and in vivo) and stable upon sterilization. Autoclavability was an important consideration, as a preservative-free, single-use BMT-NV-GEL-IM will avoid side- effects associated with repetitive application of drops containing preservatives like benzalkonium chloride (BAK). An extended in vitro release of BMT (80.23%) was observed for 10 days while the IOP lowering effect extended over 2 months with single subconjunctival injection of BMT-NV-GEL-IM in rats. No clinical signs of irritation, inflammation, or infection were observed in any injected eye, throughout the study, as also confirmed by histology. Furthermore, single administration of BMT-NV-GEL as topical drop lowered the IOP over 5 days. Presence of significant diffuse fluorescence in confocal microscopy of internal eye tissues post-in vivo application, as subconjunctival implant, even after 2 month and eye drops upto1 week provide direct evidence of successful sustained delivery. We thus provide an improved modality for antiglaucoma medication in patients who are challenged to adhere to a regimen of daily eye drops.

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.