PresbyopiaFOCUSNCT07924475
Prevalence of Presbyopia (Near Vision Fatigue) and Related Factors Among Working Adults Aged 30 to 55 Years in Shanghai
An observational study of Presbyopia, run by Shanghai Eye Disease Prevention and Treatment Center.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 30 to 55 yearsHealthy volunteers can take part
- Conditions the study is for
- Presbyopia
- How many people
- 1,366 participants
- Where
- No sites listed yet
- Study dates
- Nov 2026to Jan 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 30 to 55 years
- All sexes
- Healthy volunteers accepted
- Adult
Study population: 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.
Who may be able to join
- Aged 30 to 55 years inclusive, based on date of birth on the national identification card
- Either sex
- Employed in the current position for at least one year
- Willing to participate and able to provide written informed consent
- Able to complete the questionnaire and the ophthalmic examinations
Who cannot join
- Active ocular inflammation, significant ocular trauma, or other acute ocular condition within the past 3 months that precludes visual function testing
- Previous intraocular surgery that substantially affects refractive status or visual function assessment, such as cataract surgery or refractive lens surgery
- Obvious cognitive impairment, severe psychiatric disease, or other condition preventing cooperation with the survey and examinations
- Markedly reduced best-corrected distance visual acuity with ocular disease sufficient to explain the near vision abnormality, including but not limited to adult amblyopia, significant corneal scarring, keratoconus, severe corneal dystrophy, significant lens opacity, and severe macular or optic nerve disease
- Severe fundus or optic nerve disease, including macular degeneration, significant maculopathy, retinal detachment, optic atrophy or advanced glaucoma
- Any other condition judged by the investigators to make participation unsuitable
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Prevalence and Associated Factors of Presbyopia Among Working Adults Aged 30-55 Years in Shanghai, China: A Cross-Sectional Study
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.
Read the detailed description
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.
- Conditions
- Presbyopia
- Keywords
- Near Fatigue, Functional Presbyopia, Accommodation, Accommodation Amplitude
- Medical subject headings
- Presbyopia
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: Day 1 (At the single study visit (cross-sectional assessment))
Secondary outcomes (5)
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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: Day 1 (At the single study visit (cross-sectional assessment))
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Nov 2026
- Study startNov 2026 (estimated)
- Primary completionJan 2027 (estimated)
- Study completionJan 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for PresbyopiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Enrolment
- 1,366 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Shanghai Eye Disease Prevention and Treatment Center
- Sponsor type
- University, hospital or other
- Collaborators
- Shanghai Essilor Optical Co., Ltd.
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07924475
- Sponsor's protocol ID
- IIT2026-015
- Acronym
- FOCUS
- Status last verified
- Nov 2026
- First submitted
- 3 Nov 2026
- Last updated
- 9 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 9 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Prevalence and Associated Factors of Presbyopia Among Working Adults Aged 30-55 Years in Shanghai, China: A Cross-Sectional Study
- ClinicalTrials.gov ID
- NCT07924475
- Acronym / sponsor ID
- FOCUS / IIT2026-015
- Conditions
- Presbyopia
- Keywords
- Near Fatigue, Functional Presbyopia, Accommodation, Accommodation Amplitude
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 1,366 participants (estimated)
- Lead sponsor
- Shanghai Eye Disease Prevention and Treatment CenterUniversity, hospital or other
- Collaborators
- Shanghai Essilor Optical Co., Ltd.
- Study start
- Nov 2026 (estimated)
- Primary completion
- Jan 2027 (estimated)
- Study completion
- Jan 2027 (estimated)
- First posted
- 9 Nov 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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.
Study design
- Observational model
- Cohort
- Time perspective
- Cross-sectional
Who may qualify
- Ages
- 30 to 55 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- 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.
Key inclusion criteria (5 listed)
- Aged 30 to 55 years inclusive, based on date of birth on the national identification card
- Either sex
- Employed in the current position for at least one year
- Willing to participate and able to provide written informed consent
- Able to complete the questionnaire and the ophthalmic examinations
Key exclusion criteria (6 listed)
- Active ocular inflammation, significant ocular trauma, or other acute ocular condition within the past 3 months that precludes visual function testing
- Previous intraocular surgery that substantially affects refractive status or visual function assessment, such as cataract surgery or refractive lens surgery
- Obvious cognitive impairment, severe psychiatric disease, or other condition preventing cooperation with the survey and examinations
- Markedly reduced best-corrected distance visual acuity with ocular disease sufficient to explain the near vision abnormality, including but not limited to adult amblyopia, significant corneal scarring, keratoconus, severe corneal dystrophy, significant lens opacity, and severe macular or optic nerve disease
- Severe fundus or optic nerve disease, including macular degeneration, significant maculopathy, retinal detachment, optic atrophy or advanced glaucoma
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Prevalence of presbyopia among working adults aged 30 to 55 years in Shanghai
Time frame: Day 1 (At the single study visit (cross-sectional assessment))
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.
5 secondary outcomes
Amplitude of accommodation by age group
Time frame: Day 1 (At the single study visit (cross-sectional assessment))
Adjusted odds ratios for factors associated with presbyopia
Time frame: Day 1 (At the single study visit (cross-sectional assessment))
Awareness of presbyopia and need for near vision correction
Time frame: Day 1 (At the single study visit (cross-sectional assessment))
Correlation between presbyopia severity grade and dry eye severity grade
Time frame: Day 1 (At the single study visit (cross-sectional assessment))
Agreement between NVC mini-program outputs and subjective refraction
Time frame: Day 1 (At the single study visit (cross-sectional assessment))
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Nov 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Questions about this trial
What is this clinical trial studying?
An observational study of Presbyopia, run by Shanghai Eye Disease Prevention and Treatment Center.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 9 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Xiangui He MD, PhD (021-53555032, xianhezi@163.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Prevalence of presbyopia among working adults aged 30 to 55 years in Shanghai (time frame: Day 1 (At the single study visit (cross-sectional assessment))). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Nov 2026.