Axial Length Shortening and Choroid Thickening in Myopic Adults Treated with Repeated Low-Level Red Light

Guihua Liu; Bingqin Li; Hua Rong; Bei Du; Biying Wang; Jiamei Hu; Bin Zhang; Ruihua Wei

doi:10.3390/jcm11247498

Axial Length Shortening and Choroid Thickening in Myopic Adults Treated with Repeated Low-Level Red Light

J Clin Med. 2022 Dec 17;11(24):7498. doi: 10.3390/jcm11247498.

Authors

Guihua Liu¹, Bingqin Li¹, Hua Rong¹, Bei Du¹, Biying Wang¹, Jiamei Hu¹, Bin Zhang², Ruihua Wei¹

Affiliations

¹ Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin 300384, China.
² College of Optometry, Nova Southeastern University, Davie, FL 33314, USA.

Abstract

This study aimed to explore the effect of repeated low-level red light (RLRL) on axial length (AL), choroid blood flow, and anterior segment components in myopic adults. Ninety-eight myopic adults were randomly divided into the RLRL group (n = 52) and the control group (n = 46). Subjects in the RLRL group completed a 4-week treatment composed of a 3-min RLRL treatment session twice daily, with an interval of at least 4 h. Visits were scheduled before and on 7, 14, 21, and 28 days after the treatment. AL, subfoveal choroidal thickness (SChT), choroidal vascularity index (CVI), and anterior segment parameters were measured at each visit. A linear mixed-effects model showed that the AL of the subjects in RLRL decreased from 24.63 ± 1.04 mm to 24.57 ± 1.04 mm, and the SChT thickened by 18.34 μm. CVI had a slight but significant increase in the 0-6 zone. However, all the anterior segment parameters did not change after RLRL treatment. Our study showed that the choroid's thickening is insufficient to explain the axial length shortening. The unchanged anterior segment and improved choroid blood flow suggest that the AL shortening in this study is mainly related to changes in the posterior segment.

Keywords: adults; axial length; choroidal thickness; choroidal vascularity index; myopia; repeated low-level red light therapy (RLRL).

Grants and funding

This study was funded by grant from National Natural Science Foundation of China (funding number: 82070929), and Tianjin Key Medical Discipline (Specialty) Construction Project (funding number: TJYXZDXK-037A).