Distribution of Choroidal Thickness and Choroidal Vessel Dilation in Healthy Japanese Individuals: The Nagahama Study

Yuki Mori; Masahiro Miyake; Yoshikatsu Hosoda; Akihito Uji; Eri Nakano; Ayako Takahashi; Yuki Muraoka; Manabu Miyata; Hiroshi Tamura; Sotaro Ooto; Yasuharu Tabara; Kenji Yamashiro; Fumihiko Matsuda; Akitaka Tsujikawa; Nagahama Study Group

doi:10.1016/j.xops.2021.100033

Distribution of Choroidal Thickness and Choroidal Vessel Dilation in Healthy Japanese Individuals: The Nagahama Study

Ophthalmol Sci. 2021 Jun 10;1(2):100033. doi: 10.1016/j.xops.2021.100033. eCollection 2021 Jun.

Authors

Yuki Mori^{1

2}, Masahiro Miyake^{1

2}, Yoshikatsu Hosoda³, Akihito Uji¹, Eri Nakano¹, Ayako Takahashi¹, Yuki Muraoka¹, Manabu Miyata¹, Hiroshi Tamura^{1

4}, Sotaro Ooto¹, Yasuharu Tabara^{2

5}, Kenji Yamashiro⁶, Fumihiko Matsuda², Akitaka Tsujikawa¹; Nagahama Study Group

Collaborators

Nagahama Study Group:
Takeo Nakayama, Akihiro Sekine, Shinji Kosugi, Yasuharu Tabara, Fumihiko Matsuda

Affiliations

¹ Department of Ophthalmology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
² Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
³ Department of Ophthalmology, Osaka Red-Cross Hospital, Osaka, Japan.
⁴ Center for Innovative Research and Education in Data Science, Institute for Liberal Arts and Sciences, Kyoto University, Kyoto, Japan.
⁵ Graduate School of Public Health, Shizuoka Graduate University of Public Health, Shizuoka, Japan.
⁶ Department of Ophthalmology, Otsu Red-Cross Hospital, Otsu, Japan.

Abstract

Purpose: To report fundamental epidemiologic data for choroidal parameters such as choroidal thickness and index of choroidal vascularity in Japanese individuals and to evaluate their correlations with age, sex, systemic parameters, and other ocular parameters.

Design: Population-based cohort study.

Participants: A total of 9850 individuals participated in the first follow-up of the Nagahama Prospective Cohort for Comprehensive Human Bioscience (the Nagahama Study) conducted between 2013 and 2016.

Methods: All participants underwent standardized ophthalmic examinations, including OCT with enhanced depth imaging (EDI; RS-3000 Advance; Nidek). We manually segmented the choroidoscleral interface to measure subfoveal choroidal thickness (SFCT) and calculated the normalized choroidal intensity obtained with EDI (NCI_EDI) and choroidal vascularity index (CVI). These are indices of choroidal brightness in OCT and reportedly represent the dilation of choroidal vessels. After summarizing the age-sex stratified distributions of SFCT, NCI_EDI, and CVI, their associations with age, sex, axial length (AL), and spherical equivalent (SE) were evaluated using linear regression analysis with adjustments for possible confounders.

Main outcome measures: Distribution of SFCT, NCI_EDI, and CVI in the healthy Japanese population and their characteristics.

Results: Age-sex standardized SFCT, NCI_EDI, and CVI were 291.2 μm, 0.653, and 66.88%, respectively. In both men and women, SFCT was associated negatively with age (P < 0.001) and NCI_EDI was associated positively with age (P < 0.001). Although both SFCT and NCI_EDI did not differ significantly between men and women overall (P = 0.87 and P = 0.21, respectively), among younger participants (35-50 years of age), men showed significantly greater SFCT than women (P < 0.001). Only in men was CVI associated positively with age (P < 0.001). In the multivariable analysis, SFCT was associated significantly with age, sex, AL, SE, and the interaction term of age and sex (P < 0.001). Independent of SFCT, NCI_EDI and CVI were associated significantly with age (P < 0.001).

Conclusions: We report normative Japanese SFCT, NCI_EDI, and CVI data using a large general Japanese cohort. The association analysis of SFCT with NCI_EDI and CVI suggested that younger individuals have a more lumen-rich choroid for their choroidal thickness than older individuals.

Keywords: AL, axial length; AMD, age-related macular degeneration; CSC, central serous chorioretinopathy; CVI, choroidal vascularity index; Choroidal epidemiology; Choroidal intensity; EDI, enhanced depth imaging; FCT, parafoveal choroidal thickness; IOP, intraocular pressure; NCI, normalized choroidal intensity; NCIEDI, normalized choroidal intensity obtained with enhanced depth imaging; NFL, nerve fiber layer; Nagahama Study; OCT; OCT, optical coherence tomography; SE, spherical equivalent; SEEDS, Singapore Epidemiology of Eye Diseases Study; SFCT, subfoveal choroidal thickness; Subfoveal choroidal thickness.