Extended Ganglion Cell Layer Thickness Deviation Maps With OCT in Glaucoma Diagnosis

Area of Science:

• Ophthalmology
• Glaucoma diagnostics
• Retinal imaging analysis

Background:

• Glaucoma diagnosis relies on detecting structural changes in the optic nerve head and peripapillary region.
• Retinal ganglion cell layer (RGCL) thickness in the macula is a potential biomarker for glaucoma.
• Current diagnostic methods may benefit from enhanced quantitative and qualitative imaging analysis techniques.

Purpose of the Study:

• To evaluate the diagnostic capability of RGCL thickness measurements in the macula.
• To compare quantitative (global value, GV) and qualitative (qualitative total value, QTV) analysis of RGCL.
• To assess the impact of using conventional versus extended macular grids for RGCL analysis.

Main Methods:

• SPECTRALIS® OCT was used to measure RGCL thickness in 150 subjects (glaucoma suspects and controls).
• Quantitative (GV) and qualitative (QTV) analyses were performed using macular grids.
• Receiver operating characteristic (ROC) curves were generated to determine diagnostic accuracy (Area Under Curve, AUC).

Main Results:

• Significant differences in RGCL thickness (GV and QTV) were observed between glaucoma groups and controls, except for ocular hypertension (OHT).
• Quantitative analysis showed high AUCs for secondary open-angle glaucoma (SOAG, 0.965), primary open-angle glaucoma (POAG, 0.942), and normal tension glaucoma (NTG, 0.916).
• Qualitative analysis with an extended macular grid (eQTV) demonstrated improved AUCs for NTG (0.919), POAG (0.969), and SOAG (0.973) compared to GV.

Conclusions:

• Quantitative and qualitative RGCL thickness analysis in the macula offers diagnostic impact comparable to RNFL assessment.
• Qualitative RGCL analysis presents a potentially rapid and user-friendly tool for clinical practice.
• Utilizing an extended macular region for RGCL analysis may enhance its diagnostic performance in glaucoma detection.