Longitudinal Changes in Bleb Height, Vascularity, and Conjunctival Microcysts After Trabeculectomy

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Viscotrabeculotomy versus trabeculectomy in the surgical treatment of open angle glaucoma: a single center, randomised controlled trial

PURPOSE

The aim of the study was to compare the effect of viscotrabeculotomy and the effect of trabeculectomy on the intraocular pressure (IOP) in cases of open angle glaucoma (OAG).

STUDY DESIGN

Prospective comparative study.

PATIENTS AND METHODS

The study was conducted on 148 eyes of 148 patients (87 men) presenting with and operated upon for OAG at Mansoura Ophthalmic center of Mansoura University in Mansoura, Egypt from 2012 to 2016. Patients were randomized into viscotrabeculotomy and trabeculectomy groups. Postoperative follow up visits were scheduled at weeks 1 and 2 then months 1, 2, 3, 6, 9, 12, 15, 18, 21 and 24. Complications were noted and managed according to needs. The primary outcome measure was IOP.

RESULTS

The study was conducted on 148 eyes (74 right) of 148 patients (87 men). The mean ± SD (range, median) age of the study patients was 50.1 ± 11.5 (20-67, 53) and 51.1 ± 10.0 (27-65, 54.5) years respectively. The mean ± SD (range, median) IOP of the study eyes on maximal tolerated IOP lowering therapy was 23.15 ± 2.31 (19-30, 23.0) and 23.64 ± 1.87 (20-28, 23.0) mmHg respectively and at the end of the 24 months of follow up was 14.91 ± 2.4 (12-23, 14) and 16.64 ± 2.8 (14-25, 16) mmHg respectively (p =  < 0.0005). Notable complications included a mild hyphema in the viscotrabeculotomy group and an IOP spike in the trabeculectomy group.

CONCLUSIONS

Viscotrabeculotomy and trabeculectomy showed efficacy and safety in OAG patients. The former resulted in better IOP reduction.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.