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Updated: Jun 3, 2026
Multimodal Imaging and Spectroscopy Fiber-bundle Microendoscopy Platform for Non-invasive, In Vivo Tissue Analysis
Published on: October 17, 2016
In vivo retinal melanin detection with the calibrated depolarization index in polarization-sensitive optical
Mengyuan Ke1, Liqin Jiang2,3, Veluchamy A Barathi3,4,5
1Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria.
Significance:
A data-based calibration method with enhanced depolarization contrast in polarization-sensitive optical coherence tomography (PS-OCT) was developed and demonstrated effective for detecting melanin content in the eye.
Aim:
We aim to mitigate the dependence between the measured depolarization metric and the intensity signal-to-noise ratio (SNR) for improved visualization of depolarizing tissues, especially in low SNR regions, and to demonstrate the enhanced depolarization contrast to evaluate melanin presence.
Approach:
A function for calibrating the depolarization metric was experimentally derived from the young albino guinea pig, assuming depolarization free in the retina. A longitudinal study of guinea pigs (9 weeks) was conducted to assess the accumulation of melanin during early eye growth. Furthermore, the melanin content of the sub-macular choroid was compared in eyes with light and dark irides involving 14 human subjects in early middle adulthood.
Results:
We observed an increase in the improved depolarization contrast, which indicates potential melanin accumulation in the early eye development with age in the pigmented guinea pig eyes. We found a significant difference in melanin content between human eyes with light and dark colors.
Conclusions:
Our proposed calibration method enhanced the visualization of depolarizing structures in PS-OCT, which can be generalized to all kinds of polarization-sensitive imaging and can potentially monitor melanin in healthy and pathological eyes.
