Microstructure of parapapillary atrophy: beta zone and gamma zone

Area of Science:

• Ophthalmology
• Medical Imaging
• Glaucoma Research

Background:

• Parapapillary atrophy (PPA) is a common finding in the optic nerve head, often associated with glaucoma.
• Morphologic characterization of PPA is crucial for understanding its pathogenesis and clinical significance.

Purpose of the Study:

• To investigate the distinct morphologic features of parapapillary atrophy using enhanced depth imaging optical coherence tomography (EDI-OCT) and color fundus photography.
• To differentiate between the gamma and beta zones of PPA based on their associations with glaucoma and other ocular parameters.

Main Methods:

• A comparative observational study involving 80 normal eyes and 80 eyes with primary open-angle glaucoma.
• Measurement of gamma and beta zones of PPA on EDI-OCT images.
• Analysis of associations between zone measurements and axial length, refractive error, vertical disc diameter, age, and glaucoma status.

Main Results:

• The gamma zone was significantly associated with longer axial length, larger vertical disc diameter, older age, and the absence of glaucoma.
• The beta zone was associated with longer axial length and the presence of glaucoma.
• No significant differences in axial length or refractive error were observed between the groups.

Conclusions:

• The EDI-OCT-defined gamma zone of PPA is associated with factors like older age, myopia, larger disc size, and importantly, the absence of glaucoma.
• Conversely, the beta zone is associated with the presence of glaucoma.
• Distinguishing between the beta and gamma zones of PPA may hold clinical utility in glaucoma assessment.