Glaucoma TodayUsing Imaging to Understand the Causes and Sequelae of Hypotony

🎓 Expert Commentary / Peer Perspective

Hypotony (IOP less than 5-6 mm Hg) is a recognized complication of glaucoma filtering surgery that can produce a spectrum of structural sequelae. Slit-lamp examination and indirect ophthalmoscopy may miss subtle presentations, making multimodal imaging essential for accurate diagnosis and management planning.

Clinical Considerations

• Macular OCT detects chorioretinal folds involving the RPE and Bruch membrane in subtle hypotony maculopathy not visible on fundus exam
• B-scan ultrasound differentiates serous (hypoechoic submembrane space) from hemorrhagic (hyperechoic) choroidal detachments, a distinction that directly drives management
• Hemorrhagic choroidal detachments present more acutely with greater pain; risk factors include high preoperative IOP, hypertension, systemic anticoagulation, and postvitrectomy status
• Ultrasound biomicroscopy (UBM) identifies cyclodialysis clefts as hypoechoic spaces between the anterior chamber and suprachoroidal space, including post-MIGS cases where gonioscopy is limited by corneal edema or hyphema

Practice Applications

• Obtain macular OCT when hypotony maculopathy is suspected but fundus folds are not clearly visible
• Use B-scan ultrasound to classify anterior choroidal detachments beyond the reach of indirect ophthalmoscopy
• Integrate UBM into preoperative planning for cyclodialysis cleft repair, particularly when gonioscopy is technically limited
• Recognize refractive shift patterns post-filtering surgery as potential hypotony indicators warranting axial length and anterior chamber depth assessment