Novel Bleb Classification Following Ab Interno Implantation of Gel-Stent Using Anterior Segment Optical Coherence Tomography

Abstract

Précis: A novel qualitative tomographical classification for bleb after implantation of XEN-Gel-Stent using ab interno approach is presented. Association of anatomic patterns to intraocular pressure (IOP) and success rates (SR) illustrates that anterior segment optical coherence tomography can be useful tool in clinical guidance.Purpose: To present a novel classification of bleb resulting from ab interno implantation of XEN-Gel-Stent and report association of tomographical patterns with IOP and SR. Materials and Methods:A cross-sectional 1-armed study of patients receiving XEN-Gel-Stent. Tomographical changes in the bleb area were studied using swept-source optical coherence tomography in an early (d 29-90 postsurgery) and late (starting from d 91 postsurgery) phase. Frequency of patterns and their association with IOP and SR (defined as IOP < 18 mmHg without medications) were studied.Results: One hundred eleven examinations of 49 blebs (49 patients) were included. Three tomographical patterns at conjunctival, 4 at tenons capsule, and 2 at episcleral level were characterized. Most frequent conjunctival pattern was subconjunctival spaces (56.3% and 53.2% in the early and late phase, respectively) and associated with lower IOP (13.0 ± 6.0 mmHg) and higher SR (89%) but only in the early phase compared with other conjunctival patterns (P < 0.05). At tenons capsule level, the hyporeflective pattern was most frequent (50% and 51.9% in early and late phase) followed by the cavernous pattern. Both patterns associated with lower IOP and higher SR compared with hyper-reflective or loss of tenon changes (P < 0.005). Most blebs showed no episcleral lake (87.5% and 89.9% in early and late phase). No difference of IOP and SR was noted compared with those showing an episcleral lake. Conclusion:A practical and clinically relevant novel classification system is proposed to tomographically describe and classify blebs after implantation of XEN-Gel-Stent. Certain patterns were associated with lower IOP and higher SR.

Morphological and Dimensional Comparison of Functioning Blebs Following PRESERFLO-Microshunt and XEN-Gel-Stent, a Study Using Anterior Segment OCT

“…The majority of eyes in our cohort of functioning blebs showed subepithelial spaces which correlated in other studies with reduced IOP (9). Still, in a study of our group we were not able to nd any correlation of conjunctival changes seen using AS-OCT with the postoperative IOP in blebs after XEN (11). The surgical approach (ab-externo versus abinterno) seems not to affect the frequency of conjunctival changes in functioning blebs.…”

“…Images were classi ed qualitatively according to the Jenaer Bleb Grading System (JBGS) (11). This grading tool allows documentation of morphological changes at three anatomical levels: the conjunctiva (C0 = no changes, C1 = intraepithelial cysts and C2 = subconjunctival spaces), tenon (T0 = no changes, T1 = hyperre ective changes, T2 = hypore ective changes and T3 = cavernous changes) and the episcleral space (ES0 = no episcleral space and ES1 = episcleral space visible).…”

Comparison of Bleb Morphology following PRESERFLO® MicroShunt and Trabeculectomy Using Anterior Segment OCT

“…In contrast, the trabeculectomy-Group exhibited more anterior drainage and a combination of subconjunctival and subtenon drainage, which might have led to cavernous changes and increased conjunctival cysts. The presence of an episcleral lake was high and comparable in both groups, a well-known morphological feature in blebs created through an ab-externo approach [14,23]. In terms of quantitative comparison, we did not observe any differences in bleb dimensions (MBH, MBW, MBL) between the two groups.…”

“…This resulted in 90 scans for each bleb, which were evaluated by the same examiner (SMH) who was blinded to the clinical data. Descriptive assessment: Images were qualitatively classified according to the Jenaer Bleb Grading System (JBGS) [19]. This grading system allows for documentation of morphological changes at three anatomical levels: the conjunctiva (C0 = no changes, C1 = intraepithelial cysts, and C2 = subconjunctival spaces), Tenon's tissue (T0 = no changes, T1 = hyperreflective changes, T2 = hyporeflective changes, and T3 = cavernous changes), and the episcleral space (ES0 = no episcleral space and ES1 = episcleral space visible).…”

A Comparative Analysis of Morphology and Dimensions of Functional Blebs following PRESERFLO-Microshunt and XEN-Gel-Stent, a Study Using Anterior Segment OCT

“…Descriptive assessment: Images were qualitatively classified according to the Jenaer Bleb Grading System (JBGS) [11]. This grading system allows for the documentation of morphological changes at three anatomical levels: the conjunctiva (C0 = no changes, C1 = intraepithelial cysts, and C2 = subconjunctival spaces), tenon's tissue (T0 = no changes, T1 = hyperreflective changes, T2 = hyporeflective changes, and T3 = cavernous changes), and the episcleral space (ES0 = no episcleral space and ES1 = episcleral space visible).…”