Beta Zone and Gamma Zone Parapapillary Atrophy in Nonmyopic Eyes

Area of Science:

• Ophthalmology
• Optometry
• Anatomy

Background:

• Parapapillary atrophy (PPA) is typically associated with myopia.
• Understanding PPA in non-myopic eyes provides insights into optic nerve head biomechanics.

Purpose of the Study:

• To evaluate the locations of alpha-zone and gamma-zone PPA in non-myopic eyes.
• To investigate the relationship between PPA location and optic nerve head canal offset.

Main Methods:

• 151 non-myopic eyes with axial length < 24.0 mm were analyzed.
• Angular locations of alpha-zone and gamma-zone PPA were compared to the central retinal vascular trunk (CRVT)/Bruch's membrane opening (BMO) offset.
• Eyes were classified based on the direction and extent of CRVT/BMO offset (minimal, temporal, nasal).

Main Results:

• Significant correlations were found between CRVT/BMO offset and both alpha-zone PPA (r=-0.209, P=0.026) and gamma-zone PPA (r=-0.529, P<0.001).
• Gamma-zone PPA was associated with older age, longer axial length, and the presence of alpha-zone PPA.
• Nasal gamma-zone PPA (46.4% of cases) was linked to a superotemporal CRVT/BMO offset.

Conclusions:

• Both alpha-zone and gamma-zone PPA are present in non-myopic eyes.
• Gamma-zone PPA location, particularly nasal PPA, correlates with the direction of optic nerve head canal offset.
• Gamma-zone PPA is not exclusive to myopia and reflects the offset between the optic nerve head canal and BMO.