Three-Dimensional Structural Phenotype of the Optic Nerve Head as a Function of Glaucoma Severity

Area of Science:

• Ophthalmology
• Medical Imaging
• Artificial Intelligence

Background:

• Glaucoma is a leading cause of irreversible blindness.
• Understanding the 3-dimensional (3-D) structural changes in the optic nerve head (ONH) is crucial for diagnosing and managing glaucoma.
• Current clinical knowledge of glaucoma's intricate pathology, particularly its 3-D structural phenotype, requires enhancement.

Purpose of the Study:

• To describe the 3-D structural differences in both connective and neural tissues of the optic nerve head (ONH) between different glaucoma stages.
• To utilize traditional and artificial intelligence-driven approaches for analyzing these structural differences.
• To enhance the understanding of glaucoma pathology beyond current clinical knowledge.

Main Methods:

• A cross-sectional study involving 541 Chinese and 112 White participants was conducted.
• Optic nerve head (ONH) imaging was performed using spectral-domain optical coherence tomography.
• Visual field assessment was done using standard automated perimetry, and 3-D structural parameters were analyzed using clinician-defined metrics and geometric deep learning.

Main Results:

• The study identified distinct 3-D structural parameters of the ONH that differentiated glaucoma stages (no glaucoma, mild, moderate, advanced).
• Geometric deep learning identified 3-D structural landmarks differentiating ONHs across glaucoma severity.
• The majority of ONH structural differences occurred in early glaucoma stages, with significant involvement of both neural and connective tissues.

Conclusions:

• Complex 3-D structural differences exist in both neural and connective tissues of the ONH as a function of glaucoma severity.
• These findings provide a deeper understanding of glaucoma's structural pathology.
• Future longitudinal studies are recommended to link 3-D ONH changes to visual field deterioration for improved early detection.