Evaluating the effect of spectacle correction for refractive errors and presbyopia on cognitive function in rural older adults in China: protocol for a randomised, parallel-group, superiority trial.

Authors

Liang Lv, Fan Yang, Meng Li, Jun Xiao, Houjiang Yang, Dongfeng Li, Chunmei Hu, Yiwen Wang, Xiao Xiao, Ling Jin, Zhanrong Li, Lin Zhou, Zhengzheng Wu, Huan Wang, Yuju Wu, Huan Zhou, Nathan Congdon

Published in

BMJ open. Volume 16. Issue 10. Pages e123629. Oct 07, 2026. Epub Oct 07, 2026.

Abstract

Vision impairment and mild cognitive impairment are highly prevalent in ageing rural populations of low- and middle-income countries. Observational studies suggest that vision correction may slow cognitive decline, but robust causal evidence-particularly from rural China-is lacking, despite an ongoing randomised controlled trial (RCT) in India. Our RCT will evaluate whether providing near and/or distance vision correction can slow cognitive decline among older adults in rural China, generating context-specific evidence to guide national policy and global healthy ageing strategies.
This study is designed as an assessor-blind, parallel-group, individually RCT. A total of 964 participants (482 per arm) aged 60-79 years with correctable refractive error-related visual impairment at distance and/or near (presenting visual acuity <6/12 in the better-seeing eye, improving to ≥6/7.5 in either eye with spectacle and/or near visual acuity <6/12 at 40 cm when measured binocularly, improving to ≥6/7.5 in either eye with spectacle), rural household registration, normal hearing (defined as a hearing threshold <40 dB in at least one ear, assessed using the HearX HearTest) and Mini-Mental State Examination, Second Edition, Simplified Chinese version scores above education-specific cut-offs will be enrolled. After comprehensive eye examinations at township health centres or village clinics, intervention participants will receive distance, near or bifocal spectacles while controls will receive a prescription and spectacles at trial closeout. The primary outcome is the change in global cognitive function from baseline to the 36-month follow-up, assessed using the Chinese version of the Montreal Cognitive Assessment Basic, with and without adjustment for baseline score, age, gender, education and other potential confounders.
The protocol is approved by the Institutional Review Board of West China School of Public Health and West China Fourth Hospital, Sichuan University, China (approval number: (HXSY-BEC-S2026005)). Results will be published in a peer-reviewed journal and presented at scientific meetings.
NCT06836440, 21 April 2025, (https://clinicaltrials.gov/study/NCT06836440).

PMID:
42843862
Bibliographic data and abstract were imported from PubMed on 08 Oct 2026.

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