Factors influencing glaucoma severity in highly myopic glaucoma

Area of Science:

• Ophthalmology
• Glaucoma Research
• Ophthalmic Imaging

Background:

• High myopia is a risk factor for open-angle glaucoma (OAG).
• Optic nerve head (ONH) structure is altered in myopia, potentially complicating glaucoma diagnosis and assessment.
• Understanding ONH parameters in highly myopic OAG is crucial for evaluating disease severity.

Purpose of the Study:

• To investigate ONH parameters in highly myopic individuals with OAG.
• To assess the association between ONH parameters and glaucoma severity.
• To explore the pathways linking ONH structure to glaucomatous damage.

Main Methods:

• Cross-sectional study of 132 highly myopic OAG patients.
• Categorization into mild, moderate, and advanced glaucoma groups.
• Measurement of ONH parameters (disc area, tilt, parapapillary atrophy (PPA), lamina cribrosa (LC) metrics) and axial length (AXL).
• Statistical analyses including ANOVA, correlation, regression, and structural equation modeling (SEM).

Main Results:

• Mild glaucoma group had shorter AXL and less ONH deformation (lower disc ovality, tilt angle, β-zone PPA area, and PPA radial extent) compared to moderate and advanced groups.
• β-zone PPA area was associated with reduced ganglion cell-inner plexiform layer (GCIPL) thickness.
• SEM revealed significant pathways linking disc tilt, LC depth, GCIPL thinning, and visual field loss.

Conclusions:

• Mildly affected highly myopic OAG eyes exhibit reduced ONH deformation and shorter AXL.
• Both regression and SEM analyses confirm that ONH structural changes, specifically β-zone PPA and disc tilt, play a role in the glaucomatous damage observed in highly myopic eyes.