2.1. Participant recruitment
The study was conducted in accordance with the tenets of the Declaration of Helsinki and was approved by the Ethics Committee of Zhongshan Ophthalmic Center, Sun Yat-sen University (Guangzhou, China). Written informed consent was obtained from all participants after explanation of the nature and possible consequences of the study.
Participants with an established AC diagnosis were recruited at Zhongshan Ophthalmic Centre from December 2017 through June 2018. Both eyes of the participants were tested for all clinical parameters. The inclusion criteria and classification of AC were based on the Japanese guidelines for allergic conjunctival diseases 2017.11Potential participants were excluded if they received topical anti-bacterial treatment in a recent year; systemic antibiotics within 90 days; topical or systemic corticosteroids within 1 week; topical CsA, tacrolimus, or any systemic immunosuppressive drug within 90 days; scrape on the vernal plaque within 1 month; any other ocular surgery within 6 months; or if they presented or had a history of severe systemic allergy at the study entry. Our published metagenomic data of the 48 healthy young subjects were used as healthy controls in this study.10