Differentiating glaucoma from chiasmal compression using optical coherence tomography: the macular naso-temporal...

Area of Science:

• Ophthalmology
• Neuro-ophthalmology
• Medical Imaging

Background:

• Visual field loss patterns aid in diagnosing visual pathway pathologies.
• Distinguishing between chiasmal compression and glaucoma is clinically significant.
• Novel macular atrophy indices may improve diagnostic accuracy.

Purpose of the Study:

• To investigate if a novel macular atrophy index can differentiate chiasmal compression from primary open-angle glaucoma (POAG).
• To assess the diagnostic accuracy of the macular naso-temporal ratio (mNTR) in these conditions.

Main Methods:

• Retrospective analysis of macular optical coherence tomography (OCT) images from patients with chiasmal compression, POAG, and healthy controls.
• Calculation of the macular naso-temporal ratio (mNTR) by comparing nasal and temporal macular ganglion cell and inner plexiform layer (mGCIPL) thickness.
• Statistical analysis using multivariable linear regression and receiver operating characteristic (ROC) curves to determine diagnostic accuracy.

Main Results:

• The mNTR was significantly different between all groups: higher in POAG and lower in chiasmal compression compared to healthy controls.
• Overall mGCIPL thickness did not differentiate between chiasmal compression and POAG.
• The mNTR achieved high diagnostic accuracy: 95.3% for POAG vs. chiasmal compression, 79.0% for healthy vs. POAG, and 89.0% for healthy vs. chiasmal compression.

Conclusions:

• The mNTR demonstrates high discriminatory power between chiasmal compression and POAG.
• This ratio may offer advantages over existing metrics for detecting visual pathway damage.
• Integrating mNTR into OCT instruments could facilitate earlier diagnosis of chiasmal compression.