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Published on: September 16, 2025
Evaluating the effect of spectacle correction for refractive errors and presbyopia on cognitive function in rural
Liang Lv1, Fan Yang1, Meng Li1
1Department of Health Behavior and Social Medicine, West China School of Public Health and West China Fourth Hospital, Sichuan University, No. 16 South Renmin Road 3 Section, Chengdu 610041, Sichuan, China.
Background:
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.
Methods:
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.
Ethics And Dissemination:
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.
Trial Registration Number:
NCT06836440, 21 April 2025, (https://clinicaltrials.gov/study/NCT06836440).
