Blocking Air in the Filtering Bleb: Effects on Graft Adhesion After Descemet's Stripping Automated Endothelial Keratoplasty.

BACKGROUND: To evaluate the outcome of Descemet's stripping automated endothelial keratoplasty (DSAEK) with "blocking air" in the filtering bleb in patients with previous trabeculectomy. METHODS: In total, 299 eyes in 283 patients who underwent DSAEK were retrospectively reviewed. Endothelial graft adhesion, intraocular pressure (IOP), and air volume in the anterior chamber with (group A) or without (group B) a filtering bleb were compared between the groups. Group A was divided into two subgroups according to the presence (group A1) or absence (group A2) of air in the filtering bleb; the same three factors were compared between the subgroups. RESULTS: The graft detachment rate was significantly higher in group A (14.3%) than in group B (6.5%) (p = 0.04). IOP was significantly lower in group A than in group B before surgery (p = 0.01), at the end of surgery (p = 0.04), at three hours (p < 0.001), and one week postoperatively (p = 0.02). The graft detachment rate did not significantly differ between groups A1 and A2. There were no differences in IOP at each follow-up time, whereas there was a statistically significant increase in IOP from the preoperative measurement to the end of surgery in group A1 (21.0±7.0 mmHg) compared with group A2 (14.2±8.6 mmHg) (p = 0.02). CONCLUSIONS: The presence of blocking air in the filtering bleb helps ensure increased IOP during the early postoperative period but had no significant effect on graft detachment rates.

Fungal corneal ulcer after repair of an overhanging filtering bleb: A case report.

BACKGROUND: Overhanging filtering bleb is a common complication after trabeculectomy and surgical repair is an effective treatment when the patient presents with apparent symptoms. Filtering bleb relevant infection including in the filtering bleb itself and even endophthalmitis in some severe cases has been reported. However, corneal fungal infection after filtering bleb repair is rarely reported. CASE SUMMARY: A 57-year-old Chinese man who had sensations of redness and foreign body sensations in the left eye 3 wk after repair of overhanging filtering bleb. 3 wk ago, due to sensations of a foreign body in the left eye for 3 years with worsening for 3 mo. The patient was diagnosed as overhanging filtering bleb and underwent a repair of overhanging filtering bleb. Postoperative, the filtering bleb formed well and the intraocular pressure is normal. But the patient gradually develop redness, pain and a grey infiltrate of the cornea in the eye. Finally it developed into fungal corneal ulcer. Through asking the medical history, we found the patient had irregularly self-medicated for years with glucocorticoid eye drops for years to relieve the foreign body sensation in the eye caused by filtering bleb overhanging. Because the glucocorticoid eye drops he used years ago had provide normal sensation to the eye. After 3 mo of anti-fungal treatment, the inflammation was controlled. CONCLUSION: In addition to avoiding the development of overhanging filtering bleb after trabeculectomy, the present case report also suggests that clinicians should pay more attention to the patient's ocular self-medication history. Particularly in patients with a history of glaucoma or eye surgery. Because these patients may be exposed to more types of eye drops than other individuals, they may select the wrong medications for long-term use, based on their previous experience.

Topical Administration of Bevacizumab to Facilitate the Functional Filtering Bleb After Trabeculectomy in the Rabbit.

Purpose: To evaluate the effects of bevacizumab in 3 different application methods, subconjunctival injection (SCI), hyaluronic acid retardant (HAR), and eye drop (ED), on attenuating scar formation in the filtering bleb. Methods: Trabeculectomy (TRAB) was performed on New Zealand rabbits. TRAB rabbits were intervened with bevacizumab SCI, HAR, ED, or mitomycin C, respectively. Intraocular pressure (IOP) of 1, 7, 14, and 28 days after TRAB was recorded, and the bleb survival rate was analyzed. Bleb height, area, and vascularization were evaluated using anterior segment optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) at 7, 14 and 28 days after surgery. A histopathology examination of the bleb tissue was performed. The expression levels of vascular endothelial growth factor (VEGF)-A, interleukin (IL)-1α, tumor necrosis factor-alpha (TNF-α), transforming growth factor-ß1 (TGF-ß1), and α-smooth muscle actin (α-SMA) were measured by Western blot. Results: Bevacizumab significantly reduced postoperative IOP and increased the survival of the filtering bleb, especially in the ED group. Less vascularization was shown in the SCI, HAR, and ED groups. Histopathological results showed the fewest levels of scarring and fibrosis in the ED group. The local VEGF-A, IL-1α, and TNF-α expression levels after bevacizumab ED were decreased, combined with suppression of TGF-ß1 and α-SMA. Conclusions: Postoperative use of bevacizumab EDs was an effective application method for improving surgical outcomes after TRAB in rabbits. It might be effective in preventing scarring of the filtering bleb by antivascularization and anti-inflammation.

Role of the chloride channel blocker in the formation of filtering tract scars after glaucoma surgery in rats.

Filtration surgery is commonly performed for glaucoma treatment to reduce intraocular pressure (IOP); however, scarring of the filtering bleb is the main cause of failure. In this study, we evaluated the effects of the chloride channel blocker 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) on scar formation in filtering blebs. A glaucoma filtering surgery model was generated using Sprague-Dawley rats, divided into the control and NPPB groups receiving injections of different NPPB concentrations. The IOP of all rats decreased 1-day post-surgery and gradually increased afterward. However, IOP in rats from the NPPB groups recovered more slowly than that of the control group rats. In addition, the area and survival times of filtering blebs in rats from the NPPB groups were substantially larger and longer than those in the control group. Twenty-eight days after surgery, the protein and mRNA expression of collagen I, fibronectin and α-smooth muscle actin in the filtering area of rats from the NPPB groups were significantly lower than that in the control group rats. Collectively, our study demonstrates that NPPB inhibits filtering bleb scar formation, maintains filtering bleb morphology and prolongs filtering bleb survival time by inhibiting the differentiation of conjunctival fibroblasts and extracellular matrix synthesis.

Comparison between Surgical Techniques Used for Revision of the Filter Bleb: A Randomized Controlled Clinical Trial.

INTRODUCTION/PURPOSE: The aim of this study was to compare two surgical revision techniques in failed trabeculectomies after 6 months. METHODS: Patients diagnosed with open-angle glaucoma who underwent trabeculectomy in at least one eye with uncontrolled intraocular pressure (IOP) after trabeculectomy performed at least 6 months before were enrolled in this prospective trial. All participants underwent a complete ophthalmological examination at baseline. Randomization was performed to one eye per patient to double-masked trabeculectomy revision or needling. Patients were examined on the first day, 7 days, 14 days, and then monthly until completing 1 year after surgical intervention. All follow-up visits included the following: patients reported ocular and systemic events, best-corrected visual acuity, IOP, slit-lamp examination, and optic disc evaluation for cup-to-disc ratio. Gonioscopy and stereoscopic optic disc photographs were taken at baseline and 12 months. After 1-year, the IOP and number of medications were compared between the groups. Absolute success criteria in the study were IOP <16 mm Hg, for 2 consecutive measurements without using a hypotensive medication. RESULTS: Forty patients were included in this study. Among them, 38 completed 1-year follow-up (18 in revision group and 20 in needling group). The age ranged from 21 to 86 years, with a mean of 66.82 ± 13.44. At baseline, the average IOP was 21.64 ± 5.12 mm Hg (range from 14 to 38 mm Hg) in the entire group. All patients were using at least two classes of hypotensive eye drops, and 3 patients were using oral acetazolamide. The mean use of hypotensive eye drop medications was 3.11 ± 0.67 at the baseline for the entire group. In the present study, 58% of the patients presented complete success, 18% qualified success, and 24% failed in both groups. After 1-year treatment, both techniques were similar for IOP parameters and also for number of medications (p = 0.834 and p = 0.433, respectively). Regarding intra- or postoperative complications, one patient in each group needed a new surgical intervention, one in the needling group due to shallow anterior chamber and one in the revision group due to spontaneous Seidel sign, and one patient in the needling group underwent posterior revision due to fail. CONCLUSIONS: Both techniques were safe and effective for IOP control after 1 year of follow-up in patients who underwent to trabeculectomy more than 6 months before.

Clinical value of anterior segment optical coherence tomography­assisted 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.

Clinicopathological features of corneal invasion by filtering bleb.

PURPOSE: To describe the clinicopathological characteristics and explore the possible etiology of cornea invasion by filtering bleb (CIFB) after filtering surgery. METHODS: We reviewed 22 patients treated for CIFB between March 2005 and March 2022. The patients were followed up for more than 1 year. Slit-lamp examination, optical coherence tomography (OCT), ultrasound biomicroscopy, and histopathological examination were performed to observe the morphology of the bleb and depth of corneal invasion. Depending on the severity of the lesion, treatments consisting of local massage, acupuncture separation, or surgical resection were administered. RESULTS: The mean age of the patients was 56.3 ± 8.8 years. All patients underwent filtering surgery in the moderate or advanced stage of glaucoma. The filtering bleb was closely connected with the cornea, and its posterior boundary was locally adhered. Forward displacement of the internal opening of the filtering bleb was found in 4 of 7 surgically treated patients. OCT and pathological examination showed that the filtering blebs invaded the corneal stroma. Removal of the adhesion of the posterior boundary of the filtering bleb by different treatment methods successfully improved the patients' conditions. CONCLUSION: Filtering blebs can invade the corneal stroma. Adhesion of the posterior boundary and forward displacement of the internal opening of the filtering bleb are the possible causes of CIFB. Removal of the adhesion of the posterior boundary of the filtering bleb can halt the progression of CIFB.

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 (NCT04515017). 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.

Effect of Pharmacological Mydriasis on the Intraocular Pressure in Eyes with Filtering Blebs Compared to Normal Eyes: A Pilot Study.

AIM: To test the effect of pharmacological mydriasis on intraocular pressure (IOP) in eyes with functioning blebs compared with normal eyes. PATIENTS AND METHODS: The cross-sectional study included 39 eyes, of which 19 eyes had filtering trabeculectomy blebs (group A), and 20 eyes with no previous surgeries (group B). IOP was measured using the Goldmann applanation tonometer before, and 30 min after the application of tropicamide 1% eye drops. RESULTS: In group A eyes, the IOP level changed from 13.68 ± 3.4 mmHg before pupillary dilatation, to achieve a level of 11.95 ± 3.03 mmHg following mydriasis, with an average IOP drop of 1.73 mmHg (p < 0.0001). On the other hand, the pre-dilatation IOP in group B eyes was 15.9 ± 3.00 mmHg, had increased after mydriasis to 18.4 ± 2.9 mmHg, with an average rise of 2.5 mmHg (p < 0.0001). The difference in IOP change following mydriasis between both groups was significant (p < 0.0001). CONCLUSION: Surprisingly, pharmacological pupillary dilatation resulted in a reduction of IOP in eyes with successful trabeculectomy, which is different from the usual effect of raising the IOP as in the control group. This effect has not been previously studied.

Inferior Removal of Dislocated Polymethyl Methacrylate Intraocular Lens and Scleral Refixation in Glaucomatous Eyes.

INTRODUCTION: The aim of this study was to report a technique for the removal of dislocated polymethyl methacrylate (PMMA) intraocular lenses (IOLs) in glaucomatous eyes. METHODS: Dislocated PMMA IOLs were removed from the inferior sclerocorneal incision, and sutureless intrascleral fixation of each IOL was performed to preserve the intact superior conjunctiva and sclera for future trabeculectomy or to maintain a functional filtering bleb of trabeculectomy. RESULTS: In two cases, the condition of the bleb did not change, while the intraocular pressure improved or did not change after the procedures. IOL fixation was stable with no complications, such as tilt, decentration, or extrication of the IOL haptics. CONCLUSION: This procedure of preserving the superior conjunctiva and sclera can maintain the function of the bleb, superior cornea and sclera and may contribute to the success of future trabeculectomy.

A modified model of glaucoma filtering surgery in Sprague-Dawley rats.

Animal models are useful in glaucoma research to study tissue response to wound healing. Smaller animals such as rats offer additional advantages in terms of availability of detection antibodies and microarrays with cheaper maintenance costs. In this study, we describe a glaucoma filtering surgery (GFS) model in adult Sprague-Dawley rats by performing a sclerostomy using a 26-G needle and additionally placing a silicone tube (27 G) connecting the anterior chamber to the subconjunctival space to maintain a patent fistula for the flow of aqueous humor, thus providing a more definitive bleb. This technique will be useful in identifying and modifying newer targets in the wound healing process in order to improve surgical outcomes following GFS.

The high-pressure bleb.

A 45-year-old male presented with a slowly progressive, painless swelling in his right eye for the past 6 months. He had undergone an open globe injury repair 10 years back and an eventful cataract surgery 5 years back. The presenting visual acuity in the affected eye was perception of light with inaccurate projection of rays. The intraocular pressure was 44 mm Hg with advanced glaucomatous cupping. The swelling was identified to be a communicating sub-tenon cyst secondary to scleral wound dehiscence from secondary angle closure glaucoma. Wound re-suturing, cyst excision and diode laser cyclophotocoagulation was performed in a single sitting, with explained poor visual prognosis.

Characteristics of the Filtering Bleb and the Agreement between Glaucoma Specialist and Anterior Segment-Optical Coherence Tomography Assessment.

INTRODUCTION: This study aimed to evaluate the characteristics of the filtering bleb in failed late trabeculectomy and the agreement between glaucoma specialist assessment and anterior segment-optical coherence tomography (AS-OCT) system assessment in terms of the presence of subconjunctival fluid in the filtering bleb. METHODS: Patients with a diagnosis of glaucoma who were scheduled to undergo trabeculectomy in at least one eye and with uncontrolled intraocular pressure (IOP) were enrolled. All participants underwent a complete ophthalmological examination. The presence of fluid under the filtering bleb was first evaluated by a glaucoma specialist using biomicroscopy evaluation and then using the OCT 1000 AS-OCT Version 3.0.1.8 (Carl Zeiss Meditec, Dublin, CA, USA) system. A Kappa statistical test was used to evaluate the agreement between AS-OCT and the examiner. The correlation between conjunctiva and tenon thickness and clinical parameters was also assessed. RESULTS: Forty eyes of 40 patients were evaluated in this study. The ages ranged from 21 to 86 years, with a mean of 66.55 ± 12.33. The average IOP was 21.20 ± 4.44 mm Hg (range 14-38 mm Hg) in the entire group. The mean thickness of the conjunctiva and tenon was 302.03 ± 406.76 µm (range 251-1,616 µm). There was a significant negative correlation between the mean thickness of the conjunctiva and tenon and IOP (p = 0.045; confidence interval = -0.558, 0.024). Additionally, there was a significant negative correlation between the mean thickness of the conjunctiva and tenon, and the number of medications used at baseline (p = 0.043; confidence interval = -0.538, 0.051). There was significant negative correlation between the horizontal measurement of the bleb and the use of glaucoma medications (p = 0.017; confidence interval = -0.560, 0.004). A total of 26 patients were determined to have fluid by the examiner (glaucoma expert), and the presence of fluid in AS was confirmed in 19 patients by AS-OCT. Of the 14 patients who were determined to have an absence of fluid, this was confirmed by AS-OCT in 7 patients (Kappa = 0.231; agreement of 65.00%). CONCLUSION: There is fair agreement between glaucoma specialist assessment and AS-OCT assessment in terms of the presence of fluid in trabeculectomy. Our findings highlight the importance of AS-OCT in some patients before deciding upon a new intervention.

Unilateral spontaneous filtering bleb dissecting into the cornea in a patient with high myopia.

PURPOSE: To report a case of a unilateral spontaneous filtering bleb dissecting into the cornea in a patient with high myopia. CLINICAL CASE: A 33-year-old woman with high myopia (-18 D) presented with discomfort in the left eye. Ocular history included pars plana vitrectomy and cataract extraction and posterior chamber intraocular lens implantation in the left eye. Best-corrected visual acuity was 0.65 and intraocular pressure was 20 mmHg. Slit-lamp examination showed a filtering bleb in the upper-temporal quadrant, which extended and dissected the proximal cornea without affecting the visual axis. The morphology and content of the bleb was studied with anterior segment optical coherence tomography, which ruled out a corneal-scleral fistulization into the subconjunctival space. The spontaneous filtering bleb was resected surgically. Due to her high myopia, two strips of fascia lata were used to strengthen the area. In the postoperative period, a complete resection of the bleb was confirmed, without apparent leaking points and with a well-vascularized conjunctiva. No complications were noted. The patient maintained the same best-corrected visual acuity and intraocular pressure than before surgery. CONCLUSION: The formation of a spontaneous filtering bleb is a rare entity in patients with high myopia, whose risk increases due to their thinned sclerae. The risk is even greater if they have undergone ocular surgeries. Resection of the filtering bleb in our case halted the progression of the corneal dissection, therefore respecting the transparency of the visual axis and preserving visual acuity.

Evaluación cualitativa de la ampolla de filtración / Qualitative evaluation of filtering blebs

Se realizó una búsqueda sobre la evaluación cualitativa de la ampolla de filtración. La ampolla conjuntival es la parte visible de la cirugía filtrante, y su morfología es un indicador de factores que pueden determinar el resultado hipotensor de la cirugía y las posibles complicaciones posoperatorias. Se han desarrollado diversos estudios que relacionan la evaluación clínica de su morfología y el control de la presión intraocular, y se han establecido varios sistemas de puntuación, entre ellas: Wuerzburg Bleb Classification Score, Moorfields Bleb Grading System, Indiana Bleb Appearance Grading Scale y métodos de imagen para evaluar el segmento anterior (biomicroscopia ultrasónica, Tomografía retinal de Heidenberg y tomografía de coherencia óptica). Estos métodos proporcionan una herramienta útil para el seguimiento de la cirugía filtrante y su documentación(AU)

A review was conducted on the qualitative evaluation of the filtering bleb. The conjunctival bleb is the visible part of filtration surgery, and its morphology is an indicator of factors which may determine the hypotensive result of surgery and the possible postoperative complications. Various studies have been conducted which relate the clinical evaluation of its morphology and intraocular pressure control. Several grading systems have thus been established: Wuerzburg Bleb Classification Score, Moorfields Bleb Grading System, Indiana Bleb Appearance Grading Scale and imaging methods to evaluate the anterior segment (ultrasound biomicroscopy, Heidenberg retinal tomography and optical coherence tomography). These methods are a useful tool for the follow-up of filtration surgery and its documentation(AU)

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.

[Methods of assessing the condition of filtering bleb after glaucoma surgery]. / Metody otsenki sostoyaniya fil'tratsionnoi podushki posle khirurgii glaukomy.

Currently, there is a need to assess the condition of structures at the surgery site after glaucoma intervention due to the necessity to decide further treatment tactics after performed operations, as well as the possibility of developing more advanced methods of surgical treatment of glaucoma. Despite the fact that there are several methods of examining the filtration bleb (FB), some of them have both clear advantages and significant disadvantages. This article reviews the possibilities of using optical coherence tomography (OCT), ultrasound biomicroscopy (UBM), thermography, confocal microscopy, and the Hyperemia-3 program for assessing the structural and functional state of the FB.

Conjunctival thickness as a predictive imaging biomarker for the glaucoma filtration surgery outcome: An optical coherence tomography study.

IMPORTANCE: To analyse the preoperative conjunctival thickness in glaucomatous patients undergoing filtration surgery (FS), using optical coherence tomography (OCT). BACKGROUND: The conjunctival status represents one of the most critical determinants of the FS outcome. DESIGN: Retrospective study. PARTICIPANTS: Sixty-seven patients candidate to FS for uncontrolled glaucoma were enrolled. METHODS: OCT was performed at the superior bulbar conjunctiva before FS, and at bleb site at the last follow-up (LF-up) after surgery. MAIN OUTCOME MEASURES: Preoperative full, epithelial, and stromal conjunctival thickness (FCT, CET, CST) and reflectivity (CR), and LF-up bleb-wall thickness (BT), reflectivity (BR) and intraocular pressure (IOP), were the major outcomes. The relations between preoperative parameters and LF-up-IOP, BT and BR were calculated. RESULTS: FS was completely successful in 23 patients (group 1), successful with medications in 22 (group 2), and failed in 22 (group 3). FCT, CET and CST were lower, whereas CR higher, in group 3 compared to groups 1 and 2 (P < .05); BT was lower (P < .001), whereas BR higher (P < .05) in group 3 compared to group 1. FCT and CST were predictors of FS outcome with lower thickness associated with increased odds of failure (odds ratio 0.922, P = .08; 0.941, P = .025). LF-up-IOP inversely correlated with FCT and CST (r = -0.447, P = .003; r = -0.408, P = .007), whereas positively correlated with CR (r = 0.789, P < .001). CONCLUSIONS AND RELEVANCE: Preoperative conjunctival thickness and reflectivity show significant correlations with the FS outcome, both in terms of IOP and bleb-wall features. Therefore, they may be proposed as predictive imaging biomarkers to estimate the risk of filtration failure.

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.