Optic Nerve Head Histopathology in High Axial Myopia

Area of Science:

• Ophthalmology
• Optometry
• Medical Imaging

Background:

• High axial myopia is a significant risk factor for various ocular pathologies.
• Understanding the structural adaptations of the optic nerve head (ONH) in myopia is crucial for early detection and management of related diseases.

Purpose of the Study:

• To detail the specific morphological characteristics of the optic nerve head in eyes with high axial myopia.
• To investigate potential mechanisms underlying these observed changes.

Main Methods:

• Analysis of optic nerve head morphology using enucleated human eyes.
• Inclusion of data from population-based studies for broader applicability.

Main Results:

• Identified key features: enlarged optic disc (secondary macrodisc), widened and temporally shifted Bruch's membrane (BM) opening, and expanded parapapillary gamma and delta zones.
• Observed thinning and elongation of the lamina cribrosa and peripapillary scleral flange, alongside decreased peripapillary choroid thickness.
• Noted optic cup flattening and peripapillary intrachoroidal cavitations, potentially due to lamina cribrosa stretching.

Conclusions:

• Structural alterations in the myopic optic nerve head, such as BM opening changes, may predispose individuals to glaucomatous optic nerve damage.
• These findings offer insights into the biomechanical processes of emmetropization and myopization, particularly the role of BM growth.