Quantitative analysis of anterior segment optical coherence tomography images: the Zhongshan Angle Assessment Program

Area of Science:

• Ophthalmology
• Medical Imaging
• Glaucoma Research

Background:

• Anterior segment optical coherence tomography (AS-OCT) is crucial for visualizing anterior chamber (AC) structures.
• Accurate measurement of AC parameters is vital for diagnosing and managing conditions like glaucoma.
• Existing methods for analyzing AS-OCT images may have limitations in reproducibility.

Purpose of the Study:

• To present a novel image analysis method and software for AS-OCT images.
• To evaluate the intraobserver and interobserver reproducibility of AC parameter measurements using this software.
• To identify factors influencing measurement variability, particularly in different angle types.

Main Methods:

• AS-OCT images of wide and narrow anterior chamber angles were analyzed using proprietary software.
• The software utilized algorithms to define AC structures and measure parameters, with scleral spur location as the primary input.
• Reproducibility was assessed using limits of agreement (LOA) and coefficient of variation (CV).

Main Results:

• The software successfully measured all AC parameters in all analyzed images.
• Intraobserver variability was low for linear and angle area measurements.
• Interobserver variability was higher, particularly in narrow angles, and significantly influenced by scleral spur identification.
• Reproducibility was generally better for wide angles compared to narrow angles.

Conclusions:

• Semiautomated analysis of angle parameters from AS-OCT images introduces measurement variability.
• Observer variability in identifying the scleral spur is a key factor contributing to measurement discrepancies.
• Software evaluation must include both narrow and wide angles due to differing reproducibility.
• Future improvements in automation and image resolution are recommended for enhanced quantification.