Factors Correlated With Mid-Term Morphology of Functional Blebs Following Implantation of Preserflo MicroShunt Using AS-OCT

Abstract

Purpose Evaluating bleb morphology is crucial after glaucoma filtering surgery. Advances in anterior segment optical coherence tomography (AS-OCT) allow for objective assessment. While various parameters differentiate functional from failed blebs, limited information exists regarding variations within functional blebs. This study aimed to identify factors influencing morphology of functional blebs following implantation of Preserflo MicroShunt. Methods Eyes with functional blebs after Preserflo were retrospectively included. Age, gender, lens status, preoperative intraocular pressure (pre-IOP) and number of glaucoma medications were documented along with biometric measurements as axial length (AL), white-to-white distance, and anterior chamber depth. Postoperative data included time elapsed since surgery (TaS) and postoperative IOP (post-IOP). Bleb dimensions were measured using AS-OCT including maximal bleb height (MBH), width, length (MBL), bleb wall thickness (BWT), and bleb distance to limbus (DtL) along with dimensions of episcleral lake (maximal height, width [MLW], and length). Linear regression models were applied to correlate these parameters with bleb dimensions. Results Included were 50 eyes from 50 patients. Mean IOP decreased from 25.3 ± 10.0 to 11.9 ± 3.0 mm Hg after 278.5 ± 221.9 days after surgery. MBH correlated negatively with age (unstandardized coefficients [uSC] = −0.012) and TaS (uSC = −0.001, P = 0.008 for both). BWT correlated negatively with age (uSC = −0.013, P = 0.02), MBL with AL (uSC = −0.566, P = 0.01) and MLW with pre-IOP (uSC = −0.073, P = 0.02). DtL exhibited a positive correlation with post-IOP (uCS = 0.136, P = 0.02). Conclusions Morphology of functional blebs might be influenced by multiple factors such as age, TaS, AL, and pre- and post-IOP. Translational Relevance Age, time after surgery, axial length, and preoperative and postoperative IOP could affect the morphology of a functional bleb; hence, these factors should be taken into consideration when making treatment decisions.