Sonography versus anterior segment OCT for imaging bleb morphology after glaucoma drainage device surgery
- 1Department of Ophthalmology, University of Bonn, Bonn, Germany
- 2Institute for Medical Biometry, Informatics and Epidemiology, University of Bonn, Bonn, Germany
- 3Department of Ophthalmology, Klinikum Dortmund, University Witten/Herdecke, Dortmund, Germany
Abstract
Purpose: The PAUL® Glaucoma Implant (PGI) is increasingly used in the surgical management of complex glaucoma, but detailed evaluation of its subconjunctival bleb morphology remains challenging due to its posterior location. While ultrasonography has long been used for bleb imaging, anterior segment optical coherence tomography (AS-OCT) offers higher-resolution imaging of anterior structures. This study aimed to directly compare ultrasonography and AS-OCT in assessing bleb morphology following PGI implantation.
Methods: In this prospective observational study, 20 patients (21 eyes) with PGI underwent postoperative assessment with both AS-OCT and B-scan ultrasonography. Bleb configuration (single- vs. double-layered), bleb height, and spatial extension were evaluated and compared between modalities.
Results: Mean age was 64.0 years (SD = 16.6); 80% were male. Sonography identified double-layered blebs in 95.2% of eyes, compared to 47.7% with AS-OCT, which failed to fully visualize bleb layers in 38.1% of eyes. Sonography consistently measured greater bleb heights and lengths than AS-OCT (total bleb height 3.76 ± 1.39 mm vs. 1.77 ± 0.71 mm, p < 0.001; maximum bleb length 17.24 ± 3.17 mm vs. 2.85 ± 1.03 mm, p < 0.001).
Conclusions: Sonography provided more comprehensive visualization of PGI blebs, particularly in detecting double-layered configurations, total height and measuring full posterior extension, whereas AS-OCT offered detailed anterior segment assessment including the tube entry site and patch graft. Both modalities yield complementary information, and their combined use may enhance postoperative monitoring and early detection of bleb dysfunction.
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BibTeX
@article{schipper2026sonography,
title = {{Sonography versus anterior segment OCT for imaging bleb morphology after glaucoma drainage device surgery}},
author = {Pascal Schipper and Benjamin Aretz and Leonie Bourauel and Carolin Deubel and Michael Petrak and Frank G. Holz and Raffael Liegl and Karl Mercieca and Constance Liegl},
journal = {Graefe's Archive for Clinical and Experimental Ophthalmology},
year = {2026},
month = may,
doi = {10.1007/s00417-026-07276-3},
url = {https://doi.org/10.1007/s00417-026-07276-3},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Sonography versus anterior segment OCT for imaging bleb morphology after glaucoma drainage device surgery
AU - Pascal Schipper
AU - Benjamin Aretz
AU - Leonie Bourauel
AU - Carolin Deubel
AU - Michael Petrak
AU - Frank G. Holz
AU - Raffael Liegl
AU - Karl Mercieca
AU - Constance Liegl
PY - 2026
DA - 2026/05/20
JO - Graefe's Archive for Clinical and Experimental Ophthalmology
DO - 10.1007/s00417-026-07276-3
UR - https://doi.org/10.1007/s00417-026-07276-3
AB - Purpose: The PAUL® Glaucoma Implant (PGI) is increasingly used in the surgical management of complex glaucoma, but detailed evaluation of its subconjunctival bleb morphology remains challenging due to its posterior location. While ultrasonography has long been used for bleb imaging, anterior segment optical coherence tomography (AS-OCT) offers higher-resolution imaging of anterior structures. This study aimed to directly compare ultrasonography and AS-OCT in assessing bleb morphology following PGI implantation. Methods: In this prospective observational study, 20 patients (21 eyes) with PGI underwent postoperative assessment with both AS-OCT and B-scan ultrasonography. Bleb configuration (single- vs. double-layered), bleb height, and spatial extension were evaluated and compared between modalities. Results: Mean age was 64.0 years (SD = 16.6); 80% were male. Sonography identified double-layered blebs in 95.2% of eyes, compared to 47.7% with AS-OCT, which failed to fully visualize bleb layers in 38.1% of eyes. Sonography consistently measured greater bleb heights and lengths than AS-OCT (total bleb height 3.76 ± 1.39 mm vs. 1.77 ± 0.71 mm, p < 0.001; maximum bleb length 17.24 ± 3.17 mm vs. 2.85 ± 1.03 mm, p < 0.001). Conclusions: Sonography provided more comprehensive visualization of PGI blebs, particularly in detecting double-layered configurations, total height and measuring full posterior extension, whereas AS-OCT offered detailed anterior segment assessment including the tube entry site and patch graft. Both modalities yield complementary information, and their combined use may enhance postoperative monitoring and early detection of bleb dysfunction.
SN - 0721-832X
SN - 1435-702X
ER -