Morphometric analysis of human peripapillary retinal nerve fiber layer thickness

Area of Science:

• Ophthalmology
• Histology
• Anatomy

Background:

• The peripapillary retinal nerve fiber layer (RNFL) thickness pattern in healthy human eyes is typically characterized using imaging techniques like optical coherence tomography and scanning laser polarimetry.
• However, histologic validation provides a foundational understanding of these measurements.

Purpose of the Study:

• To characterize the normative peripapillary RNFL thickness and pattern using histologic sections from healthy postmortem human eyes.
• To establish a histologic baseline for RNFL thickness measurements.

Main Methods:

• Seventeen healthy postmortem human eyes were sectioned using the
• umbrella technique
• to create four concentric peripapillary rings (3.0, 3.5, 4.0, and 4.5 mm diameters).
• RNFL thickness was measured at 100 locations per ring, and data were averaged to determine normative thickness values.

Main Results:

• The average RNFL thickness for the 3.5-mm ring was 60.3 +/- 19.5 micrometers, with superior (75.3 +/- 26.5 mum) and inferior (69.4 +/- 22.4 microm) peaks and nasal (48.1 +/- 15 mum) and temporal (49.2 +/- 26.4 microm) troughs.
• A distinct "double-hump" pattern was observed, consistent with previous imaging studies.
• RNFL thickness decreased with larger ring diameters, but relative quadrant thickness percentages remained consistent.

Conclusions:

• Histologic data from healthy postmortem eyes confirm the characteristic peripapillary RNFL thickness pattern in normal eyes.
• These findings support and corroborate the results obtained from current RNFL imaging devices.