Assessment Of Iris Pigment Epithelium By Polarization-Sensitive Anterior Segment Optical Coherence Tomography In Healthy Adults

Published 2023 - 41st Congress of the ESCRS

Reference: PP12.11 | DOI: 10.82333/9vex-km48

Authors: Xiaoling Li ¹ , Jiang Liu* ² , Risa Higashita ³ , Lingxi Hu ⁴ , Bing Yang ⁵ , Zunjie Xiao ⁵ , Masahiro Yamanari ⁶

¹School of Ophthalmology and Optometry and Eye Hospital,Wenzhou Medical University,Wenzhou,China, ²Research Institute of Trustworthy Autonomous Systems,Southern University of Science and Technology,Shenzhen,China; Department of Computer Science and Engineering,Southern University of Science and Technology,Shenzhen,China, ³Tomey Corporation,Nagoya,Japan; Department of Computer Science and Engineering,Southern University of Science and Technology,Shenzhen,China, ⁴Department of Computer Science and Engineering,Southern University of Science and Technology,Shenzhen,China; Department of Computer Science and Engineering,University of Birmingham,Birmingham,United Kingdom, ⁵Department of Computer Science and Engineering,Southern University of Science and Technology,Shenzhen,China, ⁶Tomey Corporation,Nagoya,Japan

To assess iris pigment epithelium (IPE) features, like IPE thickness and melanin concentration rate, in healthy adults by polarization-sensitive Anterior Segment optical coherence tomography（PS-AS-OCT）and evaluate their association with demographic parameters and ocular biometric factors,including anterior chamber depth (ACD), lens thickness (LT), axial length (AL), and central corneal thickness (CCT).

This study took place at Toney Corporation, Japan.

This cross-sectional study was performed on 105 healthy volunteers. PS-AS-OCT images were taken for their left eyes. IPE area was manually segmented from the horizontal (0°–180°) scan images. The thickness and melanin concentration rate assessment was quantified at 99 evenly spaced points by the grayscale-entropy image which presents the polarization scrambling that could intrinsically distinguish melanin-containing tissues and color-entropy image in which RGB color values can indirectly quantify entropy values that reflects melanin concentration, respectively. Correlation tests were conducted between IPE parameters, demographic parameters, and ocular biometric parameters. Statistically significant was considered at the level of P < 0.05.

105 volunteers(age 39±11years) fulfilled the inclusion criteria, including 84 males and 21 females. IPE thickness (nasal 0.33±0.03mm and temporal 0.32±0.03mm) and melanin concentration rate (nasal 0.62±0.21 and temporal 0.61±0.20) failed to show a significant correlation with any demographic parameters and ocular biometric factors. When analyzed at the 99 evenly spaced points, the thickness at the spaced points of the peripheral region was negatively correlated with AL and ACD, positively correlated with LT, and the melanin concentration rate of specific points in the mid-peripheral region was negatively correlated with AL.

IPE thickness and melanin concentration rate can be estimated in vivo by PS-AS-OCT. We found that the thicknesses of the peripheral IPE increase with LT and decrease with ACD and AL. In contrast, the melanin concentration rate of specific points in mid-peripheral IPE only decreases with AL. These detailed IPE features description from healthy adults in our study will serve as reference data and further encourage the use of PS-AS-OCT to explore IPE potential function in the pathological state of the eyes. This may help assess the health of the anterior chamber or even the whole eye so that it may make diagnoses or surgical judgments in multiple ways.