Reproducibility of SD-OCT-based ganglion cell-layer thickness in glaucoma using two different segmentation...

Area of Science:

• Ophthalmology
• Medical Imaging
• Glaucoma Research

Background:

• Glaucoma diagnosis and monitoring rely on detecting structural changes in the retina.
• Spectral-domain optical coherence tomography (SD-OCT) is a key imaging modality for assessing retinal nerve fiber layer and ganglion cell complex thickness.
• Accurate and reproducible measurements of the ganglion cell-layer-plus-inner plexiform-layer (GCL+IPL) are crucial for early glaucoma detection and management.

Purpose of the Study:

• To compare the reproducibility of GCL+IPL thickness measurements derived from SD-OCT using a publicly available (Iowa) algorithm versus a commercially available (Cirrus) algorithm.
• To evaluate the reliability of these algorithms in patients diagnosed with open-angle glaucoma or suspected glaucoma.

Main Methods:

• Prospective acquisition of macula SD-OCT volumes from both eyes of glaucoma patients on two separate visits within 4 months.
• Calculation of combined GCL+IPL thickness using two distinct algorithms: a graph-theoretical approach (Iowa) and Cirrus software's ganglion cell analysis module.
• Statistical analysis focused on intraclass correlation coefficients, intervisit standard deviations, and coefficients of variation to assess reproducibility.

Main Results:

• Both algorithms demonstrated high reproducibility, with intraclass correlation coefficients of 0.98 for the Iowa algorithm and 0.95 for the Cirrus algorithm.
• The Iowa algorithm showed lower intervisit standard deviations (1.55 μm) and coefficients of variation (2.2%) compared to the Cirrus algorithm (2.45 μm and 3.5%, respectively).
• P < 0.0001 indicated statistically significant differences in reproducibility metrics between the two algorithms.

Conclusions:

• SD-OCT-based GCL+IPL thickness measurements are highly reproducible in patients with early glaucoma.
• Both public and commercial algorithms provide reliable data for GCL+IPL assessment in glaucoma, with the Iowa algorithm exhibiting slightly superior reproducibility.