Optical attenuation coefficient-based automatic segmentation of limbal epithelium and age-related differences

The limbus, located at the cornea-conjunctiva junction, houses limbal epithelial stem cells that maintain the corneal epithelium and respond to tissue damage. The limbal epithelial thickness is an indicator of corneal structural or functional alterations. This study proposes the use of optical attenuation coefficient (OAC) for automatic segmentation of limbal epithelial layer and examines age-related differences in limbal epithelial thickness and OAC values. We scanned 11 cadaveric limbal tissues from donors aged 4-96, utilizing a lab-built optical coherence tomography (OCT) system. An optimized depth-resolved estimation method was employed to estimate OAC. The limbal epithelial boundaries were detected based on OAC values to generate epithelial thickness map and en face OAC projected map. The average thickness for donors ≤65 years (Group A) was 73.9 ± 12.7 μm, thicker than the 66.0 ± 16.8 μm observed in donors >65 years (Group B). Group A's average OAC (0.80 ± 0.10 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>) was significantly higher than Group B's (0.39 ± 0.09 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>)(P<0.001). Our findings demonstrate that OAC has potential as an indicator for non-invasively screening abnormal limbal conditions in clinical practice.