Sex-Specific Differences in Circumpapillary Retinal Nerve Fiber Layer Thickness

Area of Science:

• Ophthalmology
• Medical Imaging
• Human Anatomy

Background:

• Retinal nerve fiber layer (RNFL) thickness is a key indicator in ophthalmological diagnostics.
• Age is a known factor influencing RNFL thickness.
• Understanding demographic variations in RNFL thickness is essential for normative data development.

Purpose of the Study:

• To investigate the role of sex on retinal nerve fiber layer (RNFL) thickness.
• To analyze sex-specific patterns in RNFL thickness at 768 circumpapillary locations using OCT.
• To determine the contribution of sex to RNFL thickness variance compared to other factors.

Main Methods:

• A population-based cross-sectional study involving 5646 healthy participants.
• Circumpapillary RNFL (cRNFL) thickness measured using spectral-domain OCT at 768 points.
• Statistical analyses including Student t-tests and multivariable linear regression to assess sex differences and variance contributions.

Main Results:

• Global cRNFL thickness was 1 μm thicker in females (P < 0.001).
• Significant sex effects on cRNFL thickness were observed at 56.8% of the 768 locations, with distinct regional patterns.
• Females had thicker RNFL in temporal and nasal regions; males had thicker RNFL in the superior region.

Conclusions:

• Sex is a significant determinant of cRNFL thickness, comparable in importance to age in certain regions.
• Sex-specific normative data for cRNFL thickness may enhance the accuracy of glaucoma diagnosis and monitoring.
• Detailed analysis reveals location-specific sex effects on RNFL thickness, highlighting the need for sex-adjusted reference ranges.