{
  "abstract": "Introduction The macula is a pigmented area located at the centre of the retina, responsible for central, high-resolution colour vision. Previous research has demonstrated that oral carotenoid supplementation can enhance contrast sensitivity (CS) in European populations. This study aims to investigate whether carotenoid supplementation can also improve visual function in the Chinese population.Methods and analysis The Contrast Sensitivity Vision (CSV) trial is a double-blind, randomised controlled trial conducted at the Zhongshan Ophthalmic Center in Guangzhou, China. 220 eligible Chinese adults will be randomised in a 1:1 ratio to receive either oral supplementation of 10 mg lutein, 10 mg meso-zeaxanthin and 2 mg zeaxanthin in a formula-based oil suspension (administered as one soft gel capsule) or a placebo oil soft gel capsule daily for 1 year. Participants in both groups will undergo ophthalmological study procedures including best-corrected visual acuity (BCVA), contrast sensitivity, optical coherence tomography, fundus photography and skin carotenoid examinations at baseline and at 3-month, 6-month and 12-month follow-up visits. Blood tests and a Dietary Carotenoid Screening Questionnaire will be administered at baseline and at the 12-month follow-up. Subjective visual function questionnaire interviews will be administered at baseline and at the 3-month, 6-month and 12-month follow-ups. The primary outcome will assess change in CS at 6 cycles per degree (cpd) over the 1-year study intervention. Secondary outcomes will examine CS at 6 cpd at the 3-month and 6-month follow-up, CS at other cpd, BCVA, subjective visual function and skin carotenoid levels as measured at baseline, 3-month, 6-month and 12-month follow-ups.Ethics and dissemination The CSV trial was approved by the Ethics Committee of the Zhongshan Ophthalmic Center, Guangzhou, China (No. KYPJ141-4). Participants will have the opportunity to ask questions about the trial, and written informed consent will be obtained from all participants prior to their involvement in the study. Results will be disseminated through peer-reviewed publication and conference presentations.Trial registration number NCT06098677.",
  "authors": [
    {
      "affiliations": [
        "State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China"
      ],
      "name": "Kan Xu"
    },
    {
      "affiliations": [
        "State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China"
      ],
      "name": "Xuanzhang Tang"
    },
    {
      "affiliations": [
        "State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China"
      ],
      "name": "Yurui Zhang"
    },
    {
      "affiliations": [
        "Blackmores Institute, Sydney, New South Wales, Australia"
      ],
      "name": "Jew Puay Tay"
    },
    {
      "affiliations": [
        "State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China"
      ],
      "name": "Shiran Zhang"
    },
    {
      "affiliations": [
        "State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China"
      ],
      "name": "Yimin Qin"
    },
    {
      "affiliations": [
        "State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China"
      ],
      "name": "Waihang Wong"
    },
    {
      "affiliations": [
        "State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China",
        "School of Optometry, The Hong Kong Polytechnic University, Hong Kong, People's Republic of China",
        "Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong, People's Republic of China",
        "Centre for Eye and Vision Research (CEVR), Centre for Eye and Vision Research Limited, Hong Kong, People's Republic of China"
      ],
      "name": "Mingguang He"
    },
    {
      "affiliations": [
        "State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, China"
      ],
      "name": "Xiaotong Han"
    }
  ],
  "title": "Effect of carotenoids supplementation on visual function in Chinese adults free of retinal disease: protocol for the CSV double-blind, randomised, placebo-controlled trial",
  "uid": "880e886e-839e-59fa-a705-b85a5c5fb915"
}