An observational study in Presbyopia, sponsored by Shanghai Eye Disease Prevention and Treatment Center. Not yet recruiting. Open to participants aged 30 Years to 55 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-09.
Sponsored by Shanghai Eye Disease Prevention and Treatment Center · Observational
This observational study aims to determine how common presbyopia is among working adults aged 30-55 years in Shanghai, China, and identify factors associated with it. Presbyopia is an age-related loss of the eye's ability to focus on nearby objects, which can make reading and other close-up activities difficult.
Participants will undergo eye examinations and complete questionnaires about their vision, work activities, use of digital screens, lifestyle, and need for vision correction. The study aims to obtain valid primary outcome data from at least 1,366 participants. It will also assess how closely the results of the NVC mini-program agree with a professional eye examination. No treatment will be assigned as part of the study.
This cross-sectional observational study will investigate the prevalence of presbyopia (near fatigue) and associated factors among working adults aged 30-55 years in Shanghai, China. Eligible participants must have worked in their current position for at least one year and provide written informed consent.
Industry-stratified two-stage sampling will be used, with the ISIC Rev.5 classification as the industry stratification framework. At the first stage, workplaces are randomly selected from candidate workplace rosters within each industry stratum; the study plans to include at least 15 independent workplaces covering at least 5 ISIC Rev.5 sections. At the second stage, eligible employees are randomly sampled from complete, de-duplicated employee rosters of the selected workplaces; if the number of eligible employees in a workplace does not exceed the planned invitation quota, all eligible employees are invited. The target is at least 1,366 participants with valid primary outcome data. Allowing for an estimated combined nonresponse and unusable primary outcome data rate of 20%, at least 1,708 individuals will need to be invited.
Data collection will include questionnaires and standardized ophthalmic examinations. Questionnaires will assess demographic and occupational characteristics, near-work demands, screen exposure, sleep, outdoor activities, lifestyle, ocular symptoms, awareness of presbyopia, previous correction, and correction needs and preferences. The NAVQ-P and OSDI questionnaires will assess near-vision difficulties and ocular surface symptoms. Examinations will assess distance, intermediate, and near visual acuity, refraction, near addition power (ADD), accommodative function, and ocular health. NVC mini-program outputs, including presbyopia severity categories and recommended ADD ranges, will also be recorded.
The primary outcome is the prevalence of presbyopia. Presbyopia is defined as binocular near visual acuity worse than N8 at 40 cm under best distance correction, improving by at least one line to N8 or better with additional positive spherical lenses, after excluding other ocular diseases sufficient to explain the reduction in near vision.
Secondary assessments will describe visual function, the relationship between accommodative amplitude and age, awareness of presbyopia, and correction needs. Associations with demographic, occupational, refractive, behavioral, and dry-eye-related factors will be examined. Analyses will account for industry stratification, workplace clustering, and unequal sampling probabilities as appropriate.
Agreement between NVC outputs and subjective refraction ADD will be assessed using overall percent agreement, the proportions of classifications differing by one grade and by two or more grades, and Kendall's tau-b correlation between NVC grades and clinical grades. The proportion of reference ADD values falling within the NVC-recommended ranges will also be calculated. No treatment will be assigned as part of this observational study.
336 studies on the registry are indexed under Presbyopia; 35 are open to participants now.
This study's planned enrollment of 1,366 is above the median of 88 across 52 observational studies indexed under Presbyopia.
Browse Presbyopia studies →Shanghai Eye Disease Prevention and Treatment Center is the lead sponsor of 66 studies on the registry; 30 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Working adults aged 30-55 years employed in their current position for at least one year, recruited from at least 15 independent workplaces in Shanghai covering at least 5 ISIC Rev.5 industry sectors (education; manufacturing; construction; human health and social work activities; financial and insurance activities; public administration; professional, scientific and technical activities; administrative and support service activities). Within each workplace, eligible employees are randomly sampled from complete, de-duplicated rosters; if eligible employees do not exceed the planned invitation quota, all are invited. Participants are examined regardless of presbyopia status; the target population includes people with and without presbyopia.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Prevalence of presbyopia among working adults aged 30 to 55 years in Shanghai
Proportion of participants meeting the study definition of presbyopia: binocular near visual acuity worse than N8 (equivalent to 20/50) at 40 cm under standard illumination with full distance refractive correction, improving by at least one line to N8 or better after binocular addition of plus lenses, after exclusion of organic ocular disease that could independently explain reduced near vision. Reported as a percentage with 95 percent confidence interval, overall and stratified by 5-year age group, sex, occupation, education level, refractive status and screen exposure level.
Time frame: Day 1 (At the single study visit (cross-sectional assessment))
Amplitude of accommodation by age group
Amplitude of accommodation in diopters, measured by the push-up method under full distance correction, repeated three times per eye and averaged. Reported as mean and standard deviation or median and interquartile range by 5-year age group, and used to fit the accommodation-age curve.
Time frame: Day 1 (At the single study visit (cross-sectional assessment))
Adjusted odds ratios for factors associated with presbyopia
Association of presbyopia with age, sex, education level, occupation and job type, refractive status, near-work duration, screen exposure, sleep duration and quality, outdoor activity and dry eye measures, estimated by generalized estimating equations or mixed-effects logistic regression with workplace as a clustering variable or random effect. Reported as adjusted odds ratios with 95 percent confidence intervals.
Time frame: Day 1 (At the single study visit (cross-sectional assessment))
Awareness of presbyopia and need for near vision correction
Description: Questionnaire-based assessment of awareness and understanding of presbyopia, previous care-seeking, current correction methods and wearing time, acceptance of correction options, acceptable price range, and future intention to use correction. Near vision-related quality of life assessed with the Chinese version of the Near Activity Visual Questionnaire for Presbyopia (NAVQ-P). Reported as frequencies and percentages.
Time frame: Day 1 (At the single study visit (cross-sectional assessment))
Correlation between presbyopia severity grade and dry eye severity grade
Dry eye graded as mild, moderate or severe based on the Ocular Surface Disease Index (OSDI), non-invasive tear break-up time, tear meniscus height and slit-lamp findings. Correlation with presbyopia severity grade assessed by Spearman rank correlation and, where appropriate, ordinal logistic regression adjusted for age, sex, refractive status, screen exposure and near-work load.
Time frame: Day 1 (At the single study visit (cross-sectional assessment))
Agreement between NVC mini-program outputs and subjective refraction
The near-fatigue severity grade and recommended ADD range output by the NVC mini-program will be compared with the reference ADD obtained by subjective refraction. Agreement measures include overall percent agreement, the proportion of classifications differing by one grade, the proportion differing by two or more grades, and Kendall's tau-b correlation between NVC grades and clinical grades. The proportion of reference ADD values falling within the NVC-recommended ranges will also be calculated.
Time frame: Day 1 (At the single study visit (cross-sectional assessment))
No study locations are listed for this record.
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Nov 2026; primary completion for Jan 2027, 2 months later.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Nov 2026. You cannot join it, but the record below documents what was studied.
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Shanghai Eye Disease Prevention and Treatment Center