Normative values for corneal nerve morphology assessed using corneal confocal microscopy: a multinational normative...

Area of Science:

• Ophthalmology
• Neurology
• Medical Imaging

Background:

• Corneal confocal microscopy is a novel technique for detecting nerve damage in peripheral neuropathies, especially diabetic neuropathy.
• Establishing normative reference values is essential for its clinical application.

Purpose of the Study:

• To provide worldwide age-adjusted normative values for corneal nerve fiber parameters.
• To facilitate the clinical translation and broader use of corneal confocal microscopy.

Main Methods:

• Pooled 1,965 corneal nerve images from 343 healthy volunteers across six centers.
• Used Heidelberg Retina Tomograph and standard imaging protocols.
• Analyzed images for corneal nerve fiber density (CNFD), branch density (CNBD), length (CNFL), and tortuosity (CNFT) using manual tracing and semiautomated software (CCMetrics).

Main Results:

• Significant age-dependent decrease in CNFD and CNFL.
• No significant age-related change in CNBD.
• Significant age-dependent increase in CNFT.
• Height, weight, and BMI did not affect normative values.

Conclusions:

• This multicenter study provides robust, worldwide normative reference values for corneal nerve parameters.
• These values will aid research and clinical practice in diagnosing diabetic and other peripheral neuropathies.