An ultrasound biomicroscopic study of filtering blebs after mitomycin C trabeculectomy

Comparison of the Intrableb Characteristics of Anterior Segment Optical Coherence Tomography Imaging in Trabeculectomy according to Amniotic Membrane Transplantation

INTRODUCTION

The purpose of this study was to compare the characteristics of filtering bleb with anterior segment optical coherence tomography (AS-OCT) according to amniotic membrane transplantation (AMT).

METHODS

One hundred and sixteen eyes of 103 glaucoma patients who underwent trabeculectomy with (AMT group; 85 eyes) or without AMT (control group; 31 eyes) were included. Intrableb parameters were evaluated with AS-OCT. Surgical success was defined as an intraocular pressure (IOP) ≤18 mm Hg and IOP reduction ≥20% without medication at the time of AS-OCT examination. Logistic regression analyses were performed to determine factors associated with IOP control.

RESULTS

In the eyes with successful IOP control, the fluid-filled space area, score, and height were greater for the AMT group than the control group (all ps < 0.001), while stripping layer thickness was greater and bleb wall reflectivity was lower for the control group than the AMT group (all ps < 0.001). Surgical success in the AMT group was associated with greater fluid-filled space score, lower bleb wall reflectivity, and microcyst formation (odds ratio [OR] = 8.016, 0.913, and 16.202, respectively, all ps ≤ 0.041). Lower bleb wall reflectivity alone was associated with surgical success in the control group (OR = 0.815, p = 0.019).

CONCLUSION

The extent of the fluid-filled space was associated with successful IOP control after trabeculectomy with AMT. Hyporeflective bleb wall was associated with successful IOP control in AMT and control groups.

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.

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.

Bleb analysis using anterior segment optical coherence tomography after trabeculectomy with amniotic membrane transplantation

INTRODUCTION

Little has been known about the intrableb structures associated with bleb function after trabeculectomy with amniotic membrane transplantation (AMT). The aim of this study is to analyze the characteristics of intrableb structures using anterior segment optical coherence tomography (AS-OCT) after trabeculectomy with AMT.

METHODS

A total of 68 eyes of 68 patients with primary open-angle glaucoma who underwent trabeculectomy with AMT were included. Surgical success was defined as intraocular pressure (IOP) ≤ 18 mmHg and IOP reduction of ≥ 20% without medication on AS-OCT examination. Intrableb parameters, including bleb height, bleb wall thickness, striping layer thickness, bleb wall reflectivity, fluid-filled space score, fluid-filled space height, and microcyst formation were evaluated using AS-OCT. Logistic regression analysis was performed to determine factors associated with IOP control.

RESULTS

Of the 68 eyes, 56 eyes were assigned to the success group and 12 eyes to the failure group. In the success group, bleb height (P = 0.009), bleb wall thickness (P = 0.001), striping layer thickness (P = 0.001), fluid-filled space score (P = 0.001), and frequency of microcyst formation (P = 0.001) were greater than those in the failure group. Bleb wall reflectivity was higher in the failure group than in the success group (P < 0.001). In the univariate logistic regression analysis, previous cataract surgery was significantly associated with surgical failure (odds ratio = 5.769, P = 0.032).

CONCLUSION

A posteriorly extending fluid-filled space, tall bleb with low reflectivity, and thick striping layer were characteristics of successful filtering blebs after trabeculectomy with AMT.

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.

Microcatheter-Assisted Trabeculotomy Combined With Deep Sclerectomy and Trabeculectomy in Young to Middle-Aged Adults With Advanced Primary Open-Angle Glaucoma: 1-Year Result

Objective: We aimed to evaluate the safety and clinical efficacy of ab externo microcatheter-assisted trabeculotomy combined with deep sclerectomy and trabeculectomy (MATT-DS-Trab) in the surgical management of advanced primary open-angle glaucoma (POAG).

Methods: According to the inclusion criteria, we retrospectively collected and analyzed 37 POAG cases in advanced stage who received MATT-DS-Trab. The intraocular pressure (IOP), best corrected visual acuity (BCVA), use of anti-glaucoma drugs, shape of the filtering bleb, size of the scleral lake, complications, and the surgical success rate were recorded.

Results: The mean IOP was 37.50 ± 8.11 mmHg before the operation, while it depleted to 10.08 ± 2.01 and 11.43 ± 2.07 mmHg at 1 week and 12 months after the operation, respectively (both P < 0.001 compared to preoperative IOP). From none to two kinds of anti-glaucoma drugs were used 12 months after surgery on the patients, which were significantly reduced compared with that preoperatively (P < 0.001). An L-type filtering bleb was the main form at all time points after the operation. At 12 months following surgery, an F-type filtering bleb accounted for 5.41% and no E-type filtering bleb was recorded. The length and height of the scleral lake shrunk with time, but there was no statistical significance (P > 0.05). Also, there was no correlation between the size of the scleral pool and the IOP (P > 0.05). At 12 months after the operation, the complete success rates were 94.59, 83.78, and 72.97% according to standards A (≤18 mmHg), B (≤15 mmHg), and C (≤12 mmHg), respectively. Intraoperative complications were mainly anterior chamber hemorrhage, and no complications related to the filtration bleb were observed after the operation.

Conclusion: Based on multichannel mechanisms, MATT-DS-Trab is able to effectively reduce IOP in advanced POAG patients, with few serious complications and a high success rate.

Ultrasound biomicroscopy in glaucoma assessment

Ultrasound biomicroscopy (UBM) is an important tool in the diagnosis, evaluation and follow up of glaucoma patients. Even if we are dealing with a primary angle closure glaucoma (PACG) or a primary open angle glaucoma (POAG) patient, the mechanism of angle closure can be revealed by performing an UBM. The device can help differentiate between the two types of glaucoma even in patients with opaque corneas when gonioscopy cannot be performed. Knowing the type of glaucoma is vital, especially regarding an individualized treatment, since each patient is unique and needs to be treated accordingly, in order to prevent glaucomatous optic neuropathy and visual field loss. Abbreviations: AC = anterior chamber, ICE = iridocorneal endothelial syndrome, IOP = intraocular pressure, NTG = normal tension glaucoma, PACG = primary angle closure glaucoma, PC = posterior chamber, PEX = pseudoexfoliation syndrome, POAG = primary open angle glaucoma, UBM = ultrasound biomicroscopy.

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.

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.

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.

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.

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.

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.

Effects of Regorafenib, a Multi-Kinase Inhibitor, on Conjunctival Scarring in a Canine Filtration Surgery Model in Comparison with Mitomycin-C

Regorafenib eye drops were developed for treating age-related macular degeneration. This study aimed to investigate the effects of this multi-kinase inhibitor on intraocular pressure (IOP), bleb formation, and conjunctival changes in a canine filtration surgery model. Glaucoma filtration surgery models were created in 24 eyes of 24 beagles. In experiment 1 (Ex 1), regorafenib eye drops (regorafenib group: n = 6) or a vehicle (control group, n = 6) were instilled twice daily for 4 weeks postoperatively. In experiment 2 (Ex 2), regorafenib eye drops were instilled as in Ex 1 (regorafenib group: n = 6) for 12 weeks while conventional intraoperative mitomycin-C (MMC) was utilized (MMC group: n = 6), In Ex 1, only the regorafenib group showed significant IOP reduction with a significantly higher bleb score. Subconjunctival area, collagen density, vessels, and cells showing proliferation and differentiation were lower in subconjunctival tissue in the regorafenib group. In Ex 2, no significant difference was found in IOP reduction and bleb formation between the regorafenib and MMC groups; bleb walls were significantly thicker and collagen density and vessels were higher in the regorafenib group; and no differences were observed in the above-mentioned cells. Thus, regorafenib might be a better alternative to MMC for creating thicker and less ischemic blebs in glaucoma filtration surgery.

Assessing the Status of Filtering Blebs at 5 Year Post- Trabeculectomy

BACKGROUND:

Glaucoma is a common cause of blindness in the world as well as in Vietnam. It is treated by many different methods but trabeculectomy is still the most popular and highly effective surgical method to treat this condition.

AIM:

To analyze the status of 5 years filtering blebs following trabeculectomy and to explore multiple factors associated with filtering blebs.

METHODS:

This is a retrospective, cross-sectional descriptive study. Eyes had been performed trabeculectomy for 5 years were included in these results. The filtering blebs were assessed using slit lamp and OCT. the OCT captured bleb area to evaluate fluid subconjunctival spaces, thickness and height of bleb and to evaluate the related factors

RESULTS:

A group of 106 primary glaucoma eyes of 97 patients (88 patients with 1 eye, 9 patients 2 eyes) had been performed trabeculectomy for 5 years were taken OCT anterior image. The proportion of female patients is 1.5 times that of male patients. IOP was controlled with or without topical medication in all eyes. The filtering bleb had a high echo reflection, which accounted for 42.5%, the average echo reflection was 38.6%, the low echo reflection response of 18.9%. 66% of the eyes had the aqueous space under the conjunctiva, 65.1% have the aqueous space under sclera flap, the average height of the bleb on OCT was 0.4 mm ± 0.3 mm. Young patients often have a higher rate of bleb fibrosis and loss of function than older patients

CONCLUSION:

OCT is capable of assessing the function of bleb. After 5 years of trabeculectomy, on the OCT image, most cases of blebs are maintaining drainage function.

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.

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.

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.

[Optical coherence tomography for examination of glaucoma surgery site]

The article reviews the results of using optical coherence tomography (OCT) - a non-invasive non-contact examination method for obtaining a tomographic slice image of the site of glaucoma surgery. The method helped reveal the functional relationships between the newly created outflow pathways and various parameters of the filtering bleb such as its linear dimensions, wall structure, presence of microcysts, position of drainage, etc. Due to its high resolution and noninvasiveness, OCT can be reliably used to examine the structure of aqueous outflow pathways in different postoperative periods with accuracy close to morphometric. The amount of data that had been obtained with the method has allowed the creation of new classifications and clarification of OCT-relevant prognostic signs for glaucoma surgery site.

Prediction of Surgical Outcome After Trabeculectomy for Neovascular Glaucoma With Anterior-segment Optical Coherence Tomography

PURPOSE

To determine the potential of anterior-segment optical coherence tomography (AS-OCT) to predict posttrabeculectomy outcomes in neovascular glaucoma (NVG).

PATIENTS AND METHODS

We recruited 45 eyes of 40 NVG patients who underwent trabeculectomy. The patients were divided into success and failure groups based on the posttrabeculectomy outcome after 12 months. AS-OCT findings were compared in the success and failure groups at 1 and 2 weeks and 1, 3, 6, and 12 months. We also analyzed early posttrabeculectomy bleb parameters with multiple logistic regression, stepwise multiple regression, and the receiver operating characteristic curve to evaluate the power of these parameters to predict long-term outcomes.

RESULTS

Intraocular pressure at 6 and 12 months was lower in the success group than the failure group (P<0.0016=0.0048). Reflectivity of the bleb wall was higher in the failure group than the success group throughout the study (all: P<0.0016). Age and reflectivity of the bleb wall at 1 week were risk factors for failure with odds ratios for failure of 0.91 and 1.67. The area under the receiver operating characteristic curve for reflectivity of the bleb wall at 1 week was 0.943 with the cutoff set at 128.9 (sensitivity: 85.7%; specificity: 100.0%). Stepwise multiple regression analysis showed that reflectivity of the bleb wall at 1 week independently indicated the bleb survival period (β=-0.84; P<0.001).

CONCLUSIONS

AS-OCT-measured reflectivity of the bleb wall, measured at 1 week of trabeculectomy for NVG, might be able to predict of the final status of the bleb.

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.

Anterior-Segment Optical Coherence Tomography for Predicting Postoperative Outcomes After Trabeculectomy

PURPOSE

To determine whether anterior-segment optical coherence tomography (AS-OCT) can be used to predict post-trabeculectomy bleb outcomes.

MATERIALS AND METHODS

We divided 58 eyes of 47 trabeculectomy patients into success or failure groups based on their status at 12 months after surgery. We then compared various AS-OCT measurement parameters between the two groups at 1 and 2 weeks and 1, 3, 6, and 12 months. We also analyzed the early post-trabeculectomy bleb parameters with multiple logistic regression, stepwise multiple regression, and the receiver operating characteristic (ROC) curve, to evaluate the power of these parameters to predict long-term outcomes.

RESULTS

Intraocular pressure 3 or more months after trabeculectomy was significantly lower in the success group than the failure group (all: P < 0.0016). Cleft volume was significantly higher 6 or more months after trabeculectomy in the success group than the failure group (P = 0.0027 and <0.0016). Reflectivity of the bleb wall was significantly higher in the failure group than the success group at 2 weeks and all later time points (all: P < 0.0016). Reflectivity of the bleb wall at 2 weeks after trabeculectomy was a risk factor for failure, with an odds ratio (OR) for failure of 2.48 (95% confidence interval, 1.31-4.68, increasing per 10 AU). The area under the ROC curve for reflectivity of the bleb wall at 2 weeks after trabeculectomy was 0.775 when the cutoff value was set at 122.8, with sensitivity, specificity, and OR of 78.3%, 80.0%, and 14.4, respectively. A stepwise multiple regression analysis showed that reflectivity of the bleb wall at 2 weeks was an independent factor indicating postoperative bleb survival period (β = -0.39, P = 0.007).

CONCLUSIONS

Reflectivity of the bleb wall, measured by AS-OCT, may be an early post-trabeculectomy predictor of bleb outcome.

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.

Ultrasound Biomicroscopy in Nonperforating Filtering Surgery with Intraoperative 5-fluorouracil and no implant: Long-term Results

Purpose

To evaluate the long-term morphologic changes in the anterior segment structures after nonpenetrating filtering surgery (NPFS) supplemented with 5-fluorouracil (5-FU) and no scleral implant using ultrasound biomicroscopy (UBM).

Methods

Thirteen eyes of 13 consecutive patients who underwent NPFS with intraoperative 5-FU under the conjunctiva and the scleral flap and no implant were evaluated in an observational nonrandomized, consecutive case series study conducted 2 years postoperatively. Patients were assessed for the presence of a subconjunctival filtering bleb, the volume of an intrascleral cavity, and a suprachoroidal hypoechoic area. The intraocular pressure (IOP) was measured preoperatively and postoperatively at the time of UBM.

Results

The IOP decreased significantly (p=0.01) from 24±7.6 mmHg to 13.7±4.1 mmHg. In most patients (69.2%), the postoperative IOP decreased at least 30% from the preoperative value without medications and in 84.6% with medication. UBM showed a subconjunctival empty space in 92.3% of eyes. In 84.6% of patients, an intrascleral cavity was seen, the mean volume of which was 1.68 mm3 (range, 0–4.07). We found a negative correlation between the height, width, and volume of the intrascleral lake and the IOP. In 92.3% of eyes, a hypoechoic area in the suprachoroidal space also was seen.

Conclusions

UBM showed a filtering intrascleral cavity, subconjunctival filtering bleb, and a suprachoroidal space after NPFS supplemented with 5-FU under the conjunctiva and the scleral flap without an implant.

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.

Prospective 3D Investigation of Bleb Wall after Trabeculectomy Using Anterior-Segment OCT

Purpose

We used three-dimensional anterior-segment optical coherence tomography (3D AS-OCT) to evaluate time-dependent posttrabeculectomy changes in bleb wall volume and intensity.

Methods

This prospective observational study included patients with open-angle glaucoma who underwent fornix-based trabeculectomy between January 2012 and October 2012. Twenty-nine eyes met inclusion criteria, and the bleb walls of 22 were amenable to three-dimensional analysis by 3D AS-OCT for 1 year after surgery. The high-intensity volume ratio was calculated as the proportion of the high-intensity region in the total bleb wall. Changes in the high-intensity volume ratio were of high intensity, and parameters influencing the ratio were analyzed using 3D AS-OCT.

Results

The mean high-intensity volume ratios (±SDs) were 43.5 ± 21.4, 44.1 ± 14.8, 41.5 ± 22.6, and 43.2 ± 19.7% at 0.5, 3, 6, and 12 months after trabeculectomy, respectively. When the volume ratios obtained 0.5 and 12 months posttrabeculectomy were compared, four and five eyes exhibited decreases and increases of over 20%, respectively. The volume ratios at 12 months correlated with the intraocular pressure (IOP) at that time (t = 2.44, P = 0.024) and the bleb wall vascularity score at 12 months (t = 5.44, P < 0.001).

Conclusions

The high-intensity bleb wall at 12 months posttrabeculectomy reflected the IOP and the bleb wall vascularity at that time.

Comparison of deep sclerokeratodissection, a new variant of nonpenetrating glaucoma surgery, with deep sclerectomy

PURPOSE

The aim of this study was to evaluate the safety and efficacy of deep sclerokeratodissection (DSKD), a new nonpenetrating technique in glaucoma surgery.

MATERIALS AND METHODS

Retrospective comparison between patients treated with DSKS or deep sclerectomy (DS) between 2013 and 2014. In DSKD, the first and only flap is dissected directly into clear cornea with unroofing Schlemm's canal. Beside routine clinical follow-up (visual acuity, intraocular pressure [IOP] readings, slit lamp and fundus examination), postoperative ultrasound biomicroscopy (UBM) investigation and quality of life (QoL) assessment were performed. Statistically significant differences were determined by parametric or nonparametric tests, depending on normality.

RESULTS

Twelve (38.7%) DSKDs and 19 (61.3%) conventional DS' were included in this analysis. IOP decreased significantly from 21.5 ± 9.2 mmHg to 6.2 ± 5.4 mmHg on day 1, 13.4 ± 7.7 at 1 month, 12.0 ± 4.1 at 3 months, 12.5 ± 3.1 mmHg at 6 months, and 13.4 ± 4.3 mmHg at 12 months (P < 0.01). No significant difference in the IOP was observed between the two groups at any follow-up (P > 0.1). There was no significant difference in intra- and post-operative complications, the morphology of the surgical site in the UBM as well as in the QoL assessment.

CONCLUSION

The results indicate that DSKD is a safe and efficient new variant of nonpenetrating glaucoma surgery. IOP can be lowered as effectively compared to conventional DS, with a similarly low rate of complications. Further reports are necessary to confirm these results.

Anterior segment imaging in glaucoma: An updated review

Anterior segment imaging allows for an objective method of visualizing the anterior segment angle. Two of the most commonly used devices for anterior segment imaging include the anterior segment optical coherence tomography (AS-OCT) and the ultrasound biomicroscopy (UBM). AS-OCT technology has several types, including time-domain, swept-source, and spectral-domain-based configurations. We performed a literature search on PubMed for articles containing the text “anterior segment OCT,” “ultrasound biomicroscopy,” and “anterior segment imaging” since 2004, with some pertinent references before 2004 included for completeness. This review compares the advantages and disadvantages of AS-OCT and UBM, and summarizes the most recent literature regarding the importance of these devices in glaucoma diagnosis and management. These devices not only aid in visualization of the angle, but also have important postsurgical applications in bleb and tube imaging.

A New Ultrasound Biomicroscopic Sign seen after Deep Sclerectomy (Dolphin Head Sign)

PURPOSE

To describe a new ultrasound biomicroscopic (UBM) sign seen in patients who underwent deep sclerectomy (DS) as a surgical procedure for the management of uncontrolled primary open-angle glaucoma (POAG). The presence of this sign in ultrasound biomicroscopy is suggested to be an indicator of successful surgery. We would like to name this sign as the "dolphin head sign."

DESIGN

Prospective interventional study.

MATERIALS AND METHODS

Twenty-eight eyes of 17 patients with POAG underwent DS with intraoperative mitomycin C (MMC) 0.3% applied for 2 minutes under the superficial scleral flap. Patients were followed up for a minimum of 6 months. Ultrasound biomicroscopy was done at the third postoperative month to evaluate the surgical area in both successful and failed cases.

RESULTS

The study included 28 eyes of 17 patients. The mean age of the study group was 42.90 ± 14.37 years (20-64 years). The study included 10 females and 7 males. The mean preoperative intraocular pressure (IOP) was 24.57 ± 6.37 mm Hg (20-38 mm Hg). The mean best corrected visual acuity (BCVA) was 0.57 ± 0.3 (0.05-1.00). Complete success has been achieved in 21 eyes (75%) during the follow-up period, with a mean IOP of 12.00 ± 3.86 mm Hg (6-20 mm Hg). The dolphin head sign was demonstrated only in successful cases, whereas the unsuccessful cases failed to show the typical sign.

CONCLUSION

The presence of a "dolphin head" configuration in UBM images could be taken as an indicator of successful DS. How to cite this article: Abdelrahman AM, El Cheweikh HM, El-Fayoumi DMS, Allam RSHM. A New Ultrasound Biomicroscopic Sign seen after Deep Sclerectomy (Dolphin Head Sign). J Curr Glaucoma Pract 2016;10(2):56-59.

Quantification of the filtering bleb's structure with anterior segment optical coherence tomography

BACKGROUND

The aim of the study is to determine the relationship between post-trabeculectomy bleb structure evaluated using anterior segment optical coherence tomography (AS-OCT) and postoperative intraocular pressure (IOP).

DESIGN

Rretrospective is showed for the design of this study.

PARTICIPANTS

There are twenty-seven eyes of 27 trabeculectomy patients.

METHODS

We drew contour lines for the bleb and cleft on 8-radius-scanned AS-OCT images, and determined correlations of AS-OCT measurements to postoperative IOP at 6 months.

MAIN OUTCOME MEASURES

The parameter used in this study is an anterior segment optical coherence tomography measurements of bleb structure, including cleft volume, wall volume, and the brightness of the bleb wall.

RESULTS

We found significant correlations between postoperative IOP at 6 months and cleft volume at 3 and 6 months (r = -0.56, P = 0.007 and r = -0.82, P <0.001), bleb wall volume at 6 months (r = -0.48, P = 0.042), bleb vertical brightness at 3 and 6 months (r = 0.73, P < 0.001 and r = 0.49, P = 0.040), and bleb horizontal brightness at 1 week, 2 weeks, 3 months and 6 months (r = 0.49, P = 0.016, r = 0.65, P < 0.001, r = 0.52, P = 0.013 and r = 0.71, P = 0.001). A stepwise multiple regression analysis of bleb structural measurements made ≤2 weeks postoperatively showed that the strongest independent factor indicating postoperative IOP at 6 months was bleb horizontal brightness at 2 weeks (β = 0.50, P = 0.006).

CONCLUSIONS

Early postoperative AS-OCT measurements of blebs, especially horizontal brightness of the bleb wall, were associated with postoperative IOP at 6 months. AS-OCT measurements of blebs may be useful predictors of trabeculectomy outcomes.

Morphology of functioning trabeculectomy blebs using anterior segment optical coherence tomography

Purpose:

To image trabeculectomy blebs using anterior segment optical coherence tomography (AS-OCT), and to correlate the bleb morphologic features at one month postoperatively with bleb function at six months.

Materials and Methods:

This prospective, observational study included 56 eyes undergoing trabeculectomy with MMC, followed up for minimum of six months. Postoperatively, bleb imaging was done using AS-OCT at one and six month. Bleb morphology was assessed for bleb wall reflectivity, bleb pattern in multiform reflectivity, visibility of drainage route and presence of hyper-reflectivity area. Bleb function was considered successful if IOP was <18 mmHg without medication at six month. Bleb morphology one month postoperatively was correlated with bleb function at six months.

Results:

At six months successful bleb function was noted in 44 (81.5%) eyes. Morphology of bleb at one month showed uniform bleb wall reflectivity in 6 eyes (11%) and multiform wall reflectivity in 48 eyes (89%). In eyes with multiform wall reflectivity, microcysts with multiple layers was seen in 26 eyes (48%), microcysts with subconjunctival separation in 12 eyes (22%) and only microcyst in 10 eyes (19%). When bleb features at one month were correlated with the bleb function at six months, logistic regression analysis revealed that blebs with multiform reflectivity with multiple internal layers with microcysts were associated with higher chances of success (P < 0.001).

Conclusion:

AS-OCT demonstrated early bleb morphological features that may be used to predict the functioning of a bleb. Multiform bleb wall reflectivity with a pattern of multiple internal layers and microcysts was associated with increased chances of success of a bleb.

Bleb-like Finding Caused by Idiopathic Scleral Thinning in an Eye With Absolute Glaucoma

PURPOSE

To evaluate a bleb-like finding in an eye with absolute glaucoma using anterior-segment optical coherence tomography (AS-OCT).

METHODS

A 35-year-old woman complained of sudden-onset pain in the right eye. She had been diagnosed with keratitis at 1.5 years old and the onset of secondary glaucoma was identified at 13 years old. At the age of 26 years, transscleral contact diode laser cyclophotocoagulation therapy was performed, except for the upper quadrant, because scleral thinning was noted at that time. At the age of 35 years, she was blind in her right eye and corneal opacity and a bleb-like structure in the upper conjunctiva was seen with a slit-lamp examination. This bleb-like structure was removed surgically at bulbar exenteration, and the pathology was examined.

RESULTS

AS-OCT showed a bleb-like internal structure with a single large empty space and thin scleral tissue and relatively thin walls with high optical density. Pathology indicated that the high optical density bleb wall was connective tissue. On AS-OCT, the internal surface of the empty space was very smooth, which matched the pathology. Histochemically, there were goblet cells, as in normal conjunctiva, but not in the conjunctiva over the aqueous space.

CONCLUSIONS

AS-OCT images found that the intrableb structure was in good agreement with the pathology results; these conjunctival changes were very similar to those after a standard trabeculectomy.

Visante Anterior Segment Optical Coherence Tomography Analysis of Morphologic Changes in the Anterior Segment Structures after Deep Sclerotomy Versus Phaco-Deep Sclerotomy with Intraoperative Mitomycin-C and No Implant Use

This article has been retracted.

23-gauge transconjunctival vitrectomy in eyes with pre-existing functioning filtering blebs

Background

We investigated the outcome of 23-gauge transconjunctival pars plana vitrectomy (23G PPV) for the treatment of vitreoretinal disorder in patients with prior trabeculectomy.

Methods

We retrospectively reviewed medical records of 23G PPV in 11 eyes that had functioning filtering blebs after trabeculectomy. The main outcome measures were the visual acuity, intraocular pressure (IOP) and subconjunctival fluid height in bleb by anterior segment optical coherence tomography (OCT) before and after the surgery.

Results

Eyes that had 23G PPV showed improvement of visual acuity after the surgery (P =0.003). Mean IOP was 13.82 mmHg before 23G PPV and 15.82 mmHg at 6 months postoperatively, which was statistically insignificant (P = 0.758). The bleb was observed before and after surgery using anterior segment OCT, and the difference in subconjunctival fluid was not statistically significant (P =0.172).

Conclusions

23G PPV did not adversely affect bleb function in eyes with prior trabeculectomy.

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.

An ultrasound biomicroscopy study after deep sclerectomy with supraciliary implant

OBJECTIVE

To evaluate patients 24 months after deep sclerectomy (DE) with supraciliary implant, and identify any predictive success factors by examination with ultrasound biomicroscopy (UBM) MATERIAL AND METHODS: This study included 26 eyes of 23 patients evaluated by UBM 24 months after a deep sclerectomy with a supraciliary hema implant.

RESULTS

There was a significant reduction in intraocular pressure (IOP), changing from a preoperative mean of 25.6 ± 6.4 mmHg to a postoperative mean of 16.2 ± 3.4 mmHg (P<.001). The number of preoperative glaucoma medications also decreased from 2.5 ± 0.6 drugs per patient to 0.5 ± 0.5 (P<.001). No change was observed in the best-corrected visual acuity. The anatomical characteristics of the surgical area, and its relationship with IOP were examined using UBM. There was no correlation between the level of IOP at the time of UBM and the horizontal (r=-.05: P=.71) and vertical diameter (r=-.1; P=.63), the height (r=.28; P=.25) and the volume of intrascleral space (r=-.08; P=.79), the thickness (r=-.07; P=.73) and the length (r=.39; P=.13) of trabeculo-Descemet's membrane (TDM), the presence of filtering bleb (P=.30) and the hypoechoic area in the supraciliary space (P=.24).

CONCLUSIONS

The insertion of a hema implant in the supraciliary space is an effective and safe surgery for patients with open angle glaucoma (OAG). No predictive success factors for supraciliary implant were found using the UBM study.

Tear fluid signs associated with filtration blebs, as demonstrated by three-dimensional anterior segment optical coherence tomography

Purpose

To determine the clinical features of tear fluid signs associated with filtration blebs via three-dimensional anterior segment optical coherence tomography (3D AS-OCT).

Methods

In total, 152 eyes (130 patients) with glaucoma that underwent trabeculectomy with mitomycin C were evaluated retrospectively. We investigated tear fluid signs associated with filtration blebs, using 3D AS-OCT with custom software, and compared the findings of lower tear meniscus. We also analyzed postoperative intraocular pressure and the bleb parameters of filtration blebs between eyes with and without tear fluid signs.

Results

We found tear fluid signs associated with filtration blebs in 45 (30%) of 152 eyes. The mean postoperative intraocular pressure of the eyes with the tear fluid sign in a filtration bleb was significantly lower than that in eyes without the tear fluid sign (P<0.001). Blebs with tear fluid signs have more frequent identifiable filtration openings, greater total height, increased fluid-filled cavity height, and less wall intensity compared with blebs without these signs.

Conclusion

We identified tear fluid signs in AS-OCT images on or along filtration blebs that depended on bleb morphology. The occurrence of these signs may be related to the presence of functional blebs, which may thereby control postoperative intraocular pressure.

Anterior-segment imaging for assessment of glaucoma

This article summarizes the physics, technology and clinical application of ultrasound biomicroscopy (UBM) and optical coherence tomography (OCT) for assessment of the anterior segment in glaucoma. UBM systems use frequencies ranging from approximately 35 to 80 MHz, as compared with typical 10-MHz systems used for general-purpose ophthalmic imaging. OCT systems use low-coherence, near-infrared light to provide detailed images of anterior segment structures at resolutions exceeding that of UBM. Both technologies allow visualization of the iridocorneal angle and, thus, can contribute to the diagnosis and management of glaucoma. OCT systems are advantageous, being noncontact proceedures and providing finer resolution than UBM, but UBM systems are superior for the visualization of retroiridal structures, including the ciliary body, posterior chamber and zonules, which can provide crucial diagnostic information for the assessment of glaucoma.