Factors influencing the filtration-bleb volume after Ex-PRESS^® surgery

Abstract

PurposeThe aim of this study was to investigate the factors influencing the volume of the filtration bleb after Ex-PRESS® surgery.MethodsThis was a retrospective non-randomized study. After excluding patients who had undergone an additional glaucoma surgery, 99 glaucoma patients who underwent Ex-PRESS® surgeries and were followed up for >2 years were analyzed. We used anterior segment optical coherence tomography to measure the bleb volume, and compared the volume at 1 year with that at 2 years after surgery. We also examined potential influencing factors, including age, number of medications, central corneal thickness, type of glaucoma, preoperative intraocular pressure (IOP), postoperative IOP, reduction ratio of IOP, history of trabeculotomy, and operation method (Ex-PRESS® surgery only or simultaneous cataract surgery).ResultsEx-PRESS® surgeries significantly decreased the IOP from 26.3±9.7 mmHg to 11.6±3.7 mmHg after 24 months (P<0.001). The success rate at 2 years was 81.2% (IOP ≥21 mmHg or ≥20% reduction from the baseline IOP). The results showed that age, postoperative IOP, glaucoma type, and simultaneous cataract surgeries influenced the filtration-bleb volume.ConclusionAdvanced age, higher postoperative IOP, pseudo-exfoliation glaucoma, and simultaneous cataract surgeries were all found to decrease the volume of the filtration bleb.

Early Three-Dimensional Intrableb Structural Changes in Primary-Open Angle Glaucoma and Exfoliation Glaucoma After Ex-PRESS Surgery

“…In the current study, the bleb volume decreased in the XFG group compared with the POAG group 6 months after Ex-PRESS surgery. Our results agreed with a previous report by Tojo et al 18 at 1 year after Ex-PRESS surgery. A more detailed evaluation showed that the fluid-filled space volume was smaller in the XFG group compared with the POAG group 3 and 6 months postoperatively ( Table 2 ).…”

“…For example, we focused on POAG and XFG, performed Ex-PRESS surgery with a fornix-based conjunctival flap, and analyzed the morphology in a limited region of the bleb centered on the scleral flap up to 6 months postoperatively. In the study of Tojo et al, 18 the surgical procedure and glaucoma types were similar to those of the current study, but those authors evaluated patients 1 year or more postoperatively, and several patients had markedly high IOP. Narita et al 23 performed trabeculectomy with a fornix-based conjunctival flap for several glaucoma types and evaluated patients 1 year postoperatively.…”

“…We first considered the relationship between the entire bleb and IOP because some studies have reported that the IOP is lower with a larger bleb. Tojo et al 18 reported a negative correlation between the bleb volume and IOP. Kawana et al 21 also reported that the bleb height was correlated negatively with the IOP.…”

“… 12 – 14 In contrast, long-term IOP control of XFG has been reported to be poorer than in POAG. 15 – 18 Several recent studies of bleb analysis using anterior-segment optical coherence tomography (AS-OCT) have been reported 18 – 25 ; however, most compared successful and unsuccessful blebs in subjects with several glaucoma types using a cross-sectional study design. Therefore, the differences in the postoperative courses between POAG and XFG regarding bleb formation are not well known.…”

EX-PRESS Glaucoma Filtration Device: Management of Complications

“…Another recent study evaluating Japanese patients found that advanced age, higher postoperative IOP, pseudo-exfoliation glaucoma, and simultaneous cataract surgery negatively influence the volume of the filtration bleb 2 years after surgery [15]. It must be said that in the latest study, hemoglobin-A1C was not measured, and EX-PRESS represented the first-line surgical treatment, without previous or subsequent glaucoma surgeries; therefore, it is difficult to make direct comparisons between our study and the Japanese report.…”