Inner limiting membrane bridges within Bruch's membrane defects in pathological myopia

Area of Science:

• Ophthalmology
• Histopathology
• Biomechanics

Background:

• Axially elongated eyes, often associated with myopia, exhibit structural changes.
• The inner limiting membrane (ILM) is the innermost layer of the retina.
• Bruch's membrane (BM) defects have been observed in pathological myopia.

Purpose of the Study:

• To investigate the characteristics of the inner limiting membrane (ILM) in human eyes with significant axial elongation.
• To identify specific ILM features associated with pathological myopia and axial elongation.
• To explore the relationship between ILM abnormalities and underlying retinal structural defects.

Main Methods:

• Histomorphometric analysis of human globes enucleated due to glaucoma or uveal melanomas.
• Light microscopy to identify regions with unique ILM features in axially elongated eyes.
• Correlation analysis to determine the association between ILM-bridge prevalence, axial length, and BM defects.

Main Results:

• Two eyes with marked axial elongation (30 mm and 34 mm) displayed regions of ILM presence without other retinal layers, termed ILM-bridges.
• These ILM-bridges were associated with larger underlying Bruch's membrane (BM) defects and localized scleral thinning.
• The number of ILM-bridges significantly correlated with increased axial length and BM defect prevalence, with BM defect prevalence being the sole significant factor in multivariable analysis.

Conclusions:

• ILM-bridges are observed in pathological myopia and are spatially linked to underlying BM defects.
• These findings suggest ILM-bridges may arise from local stretching and rupture of retinal layers due to BM defect-related retinal undersurface enlargement during axial elongation.
• Further research is needed to determine if the ILM's biomechanical strength plays a role in resisting myopic stretching forces.