Impact of Cataract Surgery on Filtering Bleb Morphology Identified Via Swept-source 3-dimensional Anterior Segment Optical Coherence Tomography.

PRéCIS:: Analysis of filtering bleb morphology using swept-source 3-dimensional anterior segment optical coherence tomography (3D AS-OCT) indicates that phacoemulsification can negatively impact the morphology of preexisting filtering blebs. PURPOSE: To identify the cross-sectional morphologic changes in successful filtering blebs after phacoemulsification using swept-source 3D AS-OCT. MATERIALS AND METHODS: In total, 30 phakic eyes of 29 patients with successful filtering blebs after primary trabeculectomy were included in this retrospective cohort study. Success was defined as intraocular pressure (IOP)≤15 mm Hg and a>20% reduction in IOP without glaucoma medication or additional glaucoma surgery after trabeculectomy. The subjects were classified into 2 groups according to whether they had undergone phacoemulsification or not after trabeculectomy: a phaco group and a control group. Filtering blebs were examined using swept-source 3D AS-OCT and evaluated for quantitative parameters, including maximum bleb height, maximum bleb wall thickness, and the ratio of the hyporeflective space of the bleb wall. RESULTS: Sixteen eyes were assigned to the phaco group and 14 eyes to the control group. The eyes in the control group showed no significant differences in IOP or in any of the 3D AS-OCT parameters at any of the follow-up timepoints. In the phaco group, the mean IOP increased significantly after phacoemulsification (P=0.003). Furthermore, the eyes in the phaco group showed a significant decrease in maximum bleb height (P=0.030), maximum bleb wall thickness (P=0.006), and the ratio of the hyporeflective space of the bleb wall (P=0.011) between prephacoemulsification and 1-year postphacoemulsification. CONCLUSION: Phacoemulsification can have a negative impact on filtering bleb morphology, which may lead to an IOP increase.

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.

Characteristics of successful filtering blebs at 1 year after trabeculectomy using swept-source three-dimensional anterior segment optical coherence tomography.

PURPOSE: To identify the cross-sectional characteristics of filtering blebs associated with intraocular pressure (IOP) control at 1 year after trabeculectomy with a square scleral flap and a fornix-based conjunctival flap. METHODS: A retrospective consecutive case series study was conducted. Eighty-four eyes of 79 patients who had undergone primary trabeculectomy were included. Surgical success was defined as IOP ≤15 mmHg and a >20% reduction in IOP without glaucoma medication and without additional glaucoma surgery at 1 year after trabeculectomy. The subjects were classified into two groups according to whether surgery was successful or unsuccessful. Filtering blebs were examined using swept-source three-dimensional anterior segment optical coherence tomography and evaluated for the following quantitative parameters: maximum bleb height, maximum bleb wall thickness, and ratio of hypo-reflective space of the bleb wall. RESULTS: Sixty-six eyes were determined to be successful and 18 eyes unsuccessful. Univariate analysis showed significant differences between the two groups regarding bleb height (P < 0.001), bleb wall thickness (P = 0.011), and ratio of hypo-reflective space of the bleb wall (P = 0.002). Multivariate logistic regression analysis confirmed that the bleb height was significantly associated with success in trabeculectomy [odds ratio 13.996 (95% confidence interval 1.184-165.420); P = 0.036]. CONCLUSION: A tall bleb with a thick hypo-reflective wall may be a feature of the well-functioning bleb.