Does the Location of Bruch's Membrane Opening Change Over Time? Longitudinal Analysis Using San Diego Automated Layer...

Area of Science:

• Ophthalmology
• Medical Imaging
• Glaucoma Research

Background:

• Glaucoma is a progressive optic neuropathy often monitored by tracking changes in the optic nerve head.
• The Bruch's membrane opening (BMO) is a key anatomical landmark, but its potential for longitudinal tracking has been debated.
• Accurate and reproducible methods for BMO identification are crucial for reliable glaucoma monitoring.

Purpose of the Study:

• To investigate the longitudinal stability of the BMO location in healthy and progressing glaucoma eyes.
• To validate an automated algorithm for BMO segmentation on Cirrus high-definition optical coherence tomography (HD-OCT) images.

Main Methods:

• A longitudinal study followed 95 eyes (35 glaucoma, 60 healthy) for an average of 3.7 years.
• BMO points were manually and automatically delineated on Cirrus HD-OCT B-scans to assess segmentation reproducibility.
• 3D spatial point-by-point analysis of BMO location changes (x, y, z) was performed on aligned images.

Main Results:

• Small, nonsignificant changes in BMO location were observed over time in both healthy and glaucoma eyes (P > 0.30).
• The automated BMO segmentation algorithm demonstrated excellent reproducibility, comparable to manual delineation (ICC ~98%, CV ~2%).

Conclusions:

• The BMO location is stable over 3-4 years in both healthy and glaucoma eyes.
• This stability confirms the BMO's utility as a fixed reference point for glaucoma progression monitoring.
• Automated BMO segmentation using Cirrus HD-OCT is a reproducible and reliable method.