Asymmetric Retinal Nerve Fiber Layer Defects in Early Glaucoma: A Focus on Superior-Inferior Depth Variability.

Area of Science:

• Ophthalmology
• Neuroscience
• Medical Imaging

Background:

• Glaucoma is a progressive optic neuropathy characterized by retinal nerve fiber layer (RNFL) damage.
• Early detection of RNFL defects is crucial for timely intervention and vision preservation.

Purpose of the Study:

• To investigate and compare the characteristics of RNFL defects in the inferior and superior retina in patients with early glaucoma.
• To identify potential asymmetries in RNFL damage between these retinal regions.

Main Methods:

• A cross-sectional study involving 103 eyes with early glaucoma (visual field mean deviation [MD] ≥ -6.0 dB).
• 131 RNFL defects were identified using OCT enface imaging.
• RNFL defect location, distribution, and depth (assessed by cpRNFL thickness difference from normal) were analyzed and compared between inferior and superior retinal regions.

Main Results:

• RNFL defects were found in both inferior (51.9%) and superior (48.1%) retina.
• Defects were angularly closer to the foveola and more localized in the inferior retina compared to the superior retina.
• RNFL defects were significantly deeper in the inferior retina (68.4% thinning) than in the superior retina (55.1% thinning), with deep defects being more frequent inferiorly (72.1% vs. 28.5%).

Conclusions:

• Significant differences exist in the location, distribution, and depth of RNFL defects between the inferior and superior retina in early glaucoma.
• The inferior retina exhibits more localized and deeper RNFL thinning, even in early stages of the disease.
• Understanding these asymmetrical characteristics can enhance the initial diagnosis and management of glaucoma.