The CLASS Surgical Site Characteristics in a Clinical Grading Scale and Anterior Segment Optical Coherence Tomography: A One-Year Follow-Up

Abstract

Purpose We combined a clinical grading scale and swept source anterior segment OCT to describe the successful and failed CLASS. Material and Methods 23 patients in the successful group and 17 patients in the failed group were compared in terms of the IBAGS grades and AS-OCT findings at one, three, and twelve months postoperatively. Results The majority in the successful group presented shallow blebs (91%, 57%, and 52% at 1M, 3M, and 12M, resp.). 59% of the failed group presented no bleb (H0 E0) from the early postoperative period with the rate increasing to 88% at 3M and 100% at 12M. The scleral lake was detected in all the successful patients. The successful group showed significantly higher rates of TDM integrity (P < 0.001), IF (P < 0.001), and SCF (P < 0.05), but there were no significant differences in the rates of microcysts between the groups (P > 0.05). We found a significant decrease in the SL anteroposterior extent (P=0.003) and SL height (P < 0.001) over time, with no significant correlation between the above parameters and IOP. Conclusions The subconjunctival bleb may be a sign of the successful CLASS when it matches the AS-OCT findings of TDM integrity, maintained scleral lake, and intrascleral fluid. A validated OCT pixel intensity measurement is required to evaluate the bleb reflectivity.

Microcatheter-Assisted Trabeculotomy Combined With Deep Sclerectomy and Trabeculectomy in Young to Middle-Aged Adults With Advanced Primary Open-Angle Glaucoma: 1-Year Result

“…In addition, there was no significant correlation between the scleral pool size by UBM and the IOP after surgery. Similar results were determined in the studies by 36). This indicates that the drop in IOP may not depend on the size and shape of the scleral cistern; on the contrary, the presence of the scleral cistern is very important for IOP reduction.…”

Analysis of bleb morphology after CLASS with ultrasound biomicroscopy and clinical grading scale

“…In addition, we noticed that the bleb blood vessels in the surgical area showed mild or moderate congestion 1 month after surgery, which might be associated with postoperative inflammatory responses, stimulation by postoperative eye drops, or filtration route scarring. Jankowska-Szmul and Wylegala 5 also found that patients in the successful group after CLASS all exhibited mild vasculature (V2). However, interestingly, nobody in the successful group showed moderate vasculature (V3), but V3 was present in all failed patients in the early stage after CLASS.…”

“…Therefore, larger blebs were correlated with lower IOP. Jankowska-Szmul and Wylegala 5 observed bleb morphology after CLASS. One month after surgery, the majority of patients in the successful group presented diffuse blebs and had an H1 percentage of 91%, whereas the majority of patients in the failed group presented no blebs and had an H0E0 percentage of 59%.…”

“…Mavrakanas et al 6 showed that intrascleral bleb height was negatively correlated with postoperative IOP in eyes with clinically flat blebs after deep sclerectomy with collagen implant, indicating that intrascleral filtration played an important role in lowering IOP. Jankowska-Szmul and Wylegala 5 and Khairy et al 17 showed that the correlation between scleral lake size and TDM and IOP was relatively weak. Cabrejas et al 18 showed that thinner TDM were significantly correlated with lower IOP 1 month after surgery.…”

“…4 Although subconjunctival filtration is controversial, some studies suggest that the mechanism of aqueous outflow may be the filtration from the scleral wound and the percolation to the supraciliary space, rather than the transscleral percolation to the subconjunctival space, and so it seems to be less dependent on the external bleb formation. 5,6 The clinical grading system of the Indiana Bleb Appearance Grading Scale (IBAGS) evaluates the bleb height, extent, vascularity, and leakage (Seidel test) which are used to evaluate external filtering bleb morphology. 7 Ultrasound biomicroscopy (UBM) inspection techniques can display a higher resolution of the internal features of filtering blebs and the sclera in the surgical area, allowing us to better understand the structural changes caused by filtration surgery.…”