Measurements of OCT Angiography Complement OCT for Diagnosing Early Primary Open-Angle Glaucoma

Area of Science:

• Ophthalmology
• Medical Imaging
• Glaucoma Research

Background:

• Primary open-angle glaucoma (POAG) is a leading cause of irreversible blindness.
• Early detection and monitoring of glaucoma progression are critical for preserving vision.
• Assessing microvascular changes alongside structural measures may improve diagnostic accuracy.

Purpose of the Study:

• To compare circumpapillary capillary density (cpCD) with retinal nerve fiber layer (RNFL) thickness in early POAG.
• To characterize the relationship between cpCD, RNFL thickness, and visual function.
• To evaluate the diagnostic performance of cpCD and RNFL thickness in detecting glaucoma.

Main Methods:

• A cross-sectional study involving healthy eyes, preperimetric eyes, and mild POAG eyes.
• Measurements of global and regional RNFL thickness and cpCD obtained using OCT and OCT angiography (OCTA).
• RNFL thickness and cpCD values normalized to a relative loss scale for comparison.

Main Results:

• Both RNFL thickness and cpCD decreased with increasing glaucoma severity.
• cpCD loss was generally greater than RNFL thickness loss in preperimetric and mild POAG.
• Global cpCD measurements demonstrated higher diagnostic accuracy than RNFL thickness for detecting early glaucoma.
• Visual function was significantly associated with both RNFL thickness and cpCD.

Conclusions:

• Capillary density loss is more pronounced than RNFL thickness loss in early glaucoma.
• RNFL thickness and cpCD are complementary measures for detecting early POAG.
• Microvascular assessments, particularly cpCD, offer valuable insights into glaucoma progression and visual function.