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PROductiviteitsstudie van de eliminatie van presbyopie bij plattelandsbewoners III (PROSPERIII)

3 november 2026 bijgewerkt door: Nathan Congdon, Queen's University, Belfast

Effecten van brillencorrectie bij dichtbij zien op werkbehoud onder arbeiders in textielfabrieken in India

The investigators will conduct an embedded mixed methods study in which the primary approach is a randomized controlled trial (RCT), and the secondary or embedded approach is a descriptive qualitative study. The aim of the RCT is to assess the impact of presbyopic correction on workplace productivity and retention in the textile industry in a low middle-income country. Additional qualitative data will be collected to enhance understanding of factors linked to reasons why enrolled sew-ers left their job during the study. Participants will be textile workers aged 30 years and above with uncorrected presbyopia who are employed by Shahi Exports Private Limited in Karnataka, India.

Studie Overzicht

Toestand

Voltooid

Conditie

Interventie / Behandeling

Gedetailleerde beschrijving

Globally, 1.1 billion people lack a simple pair of reading glasses to correct impaired near vision, called presbyopia. Presbyopia can begin as early as age 30 years, commonly becomes functionally apparent by 40, and is essentially complete by 55 meaning that presbyopia is most common at the height of the working years. The global productivity loss due to uncorrected presbyopia has been estimated to exceed US$25 billion, and presbyopia is shown to be associated with significant impairment in activities of daily living. There is paucity in trial evidence of the impact on near vision spectacle correction on work productivity and workplace retention. The largest reported effect sizes among such trials (specifically for productivity) was the PROSPER trial, which showed that providing inexpensive near vision glasses increased the daily weight of tea picked among presbyopic, mostly-female Indian agricultural workers by more than 5 kg (21.7%) compared to those in the control group.

Study Plan: The investigators will choose 1260 textile workers aged 30 years and above with uncorrected presbyopia who are employed by Shahi Exports Private Limited in Karnataka, India. They will be randomly assigned into one of two groups: a group receiving free reading glasses within one week of undergoing vision assessment ("Intervention") or a group receiving identical reading glasses at the end of the assessment period ("Control").The main study outcome will be the proportion of workers who continue working at the factories in the intervention group (as opposed to control). The investigators anticipate that the glasses intervention will increase retention by 20% in the Intervention group at 1 year.

The study will also assess the workers' efficiency, why they have left employment, how satisfied and valued they felt at their work and how often they use their glasses for work. These other outcomes will help the investigators to better understand the causal pathway between vision and work retention. The investigators will also study the total cost of providing glasses per additional worker retain their employment.

Research question: Will providing free glasses to presbyopic Indian textile workers increase work retention?

Design: Investigator-masked, multi-center randomized controlled trial with a qualitative component

Rationale: Although presbyopia is safely, effectively and inexpensively treated with glasses, rates of optical correction in LMICs are as low as 10%. The way in which firms manage workers has profound implications for performance by way of worker attendance, retention, and productivity. Similarly, worker engagement, and the extent to which workers feel valued, is a key determinant of firm performance. As the low-skill workforce in many developing countries transitions rapidly from agriculture to industrial work, employers struggle with high worker turnover due to poor working conditions, low pay, and restricted worker rights. Few trials have been published which address the question of whether healthcare interventions can improve work performance as well as workplace retention, especially among persons over the age of 40 in low and middle-income countries (LMICs). There is interest in understanding if these results obtained in an agricultural setting can be extended to other financially-important sectors.

Methods: The investigators will choose 1260 textile workers aged 30 years and above with uncorrected presbyopia who are employed by Shahi Exports Private Limited in Karnataka, India. They will be randomly assigned into one of two groups: a group receiving free reading glasses within one week of undergoing vision assessment ("Intervention") or a group receiving identical reading glasses at the end of the assessment period ("Control").

The main outcome 18 month later will be work retention; secondary outcomes are workers' efficiency, the reasons the workers left their employment, satisfaction and perceived self-valued at work and glasses wear adherence at work. Attitudes about presbyopia and spectacle use and intervention cost-effectiveness will be studied.

Studietype

Ingrijpend

Inschrijving (Werkelijk)

1291

Fase

  • Niet toepasbaar

Contacten en locaties

In dit gedeelte vindt u de contactgegevens van degenen die het onderzoek uitvoeren en informatie over waar dit onderzoek wordt uitgevoerd.

Studie Locaties

    • Karantaka
      • Bengaluru, Karantaka, Indië, 560102
        • Good Business Lab

Deelname Criteria

Onderzoekers zoeken naar mensen die aan een bepaalde beschrijving voldoen, de zogenaamde geschiktheidscriteria. Enkele voorbeelden van deze criteria zijn iemands algemene gezondheidstoestand of eerdere behandelingen.

Geschiktheidscriteria

Leeftijden die in aanmerking komen voor studie

30 jaar en ouder (Volwassen, Oudere volwassene)

Accepteert gezonde vrijwilligers

Nee

Geslachten die in aanmerking komen voor studie

Allemaal

Beschrijving

Inclusion Criteria:

  • Aged 30 years and above
  • Distance visual acuity >= 6/12 in both eyes
  • Presence of presbyopia, defined as the inability, correctable with reading glasses, to read the N8 line using both eyes together, on a tumbling near vision chart at a distance of 25cm, 30cm, 40cm, and 50cm based on workers working distance
  • Employed at the factory for >=3months in the sewing department

Exclusion Criteria:

  • Current ownership of reading or distance glasses (regardless of accuracy)
  • Obvious evidence of ocular disease in either eye detected during the eye examination, or history of such disease based on self-report
  • Low likelihood of completing follow-up in the study due to current plans to move out of the area or leave employment at Shahi during the follow-up period

Studie plan

Dit gedeelte bevat details van het studieplan, inclusief hoe de studie is opgezet en wat de studie meet.

Hoe is de studie opgezet?

Ontwerpdetails

  • Primair doel: Behandeling
  • Toewijzing: Gerandomiseerd
  • Interventioneel model: Parallelle opdracht
  • Masker: Dubbele

Wapens en interventies

Deelnemersgroep / Arm
Interventie / Behandeling
Experimenteel: Intervention

Workers assigned to the intervention group will receive free spectacles of a design they select, based on the worker's measured refractive power and dispensed one week later at the factory by the study ophthalmic personnel.

Intervention group workers receive free glasses within one week of undergoing vision assessment (May 2022). The duration of the treatment for the Intervention participants will depend on when they leave employment at the factor. If they stayed for the full duration of the trial, they will have undergone a maximum of 18 months (December 2023).

Andere namen:
  • Bril
  • Leesbril
Geen tussenkomst: Control

Workers assigned to the Control group will receive similar free glasses at the end of the study assessment (18 months).

Wat meet het onderzoek?

Primaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Work retention
Tijdsspanne: September 2022 to May 2024; Over the 18 month follow-up period from enrolment to study completion

Proportion of textile workers who continue to work at the textile factories assessed from trial entry to closure as recorded in Shahi's Human Resource Management Database

September 2022 to May 2024; Over the 18 month follow-up period from enrolment to study completion

Secundaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Compliance with spectacle wear
Tijdsspanne: 3, 6, 9, 12, 15 and 18 months after enrolment

Actual presence of spectacles on the worker's face at work as reported by supervisor at the time of unannounced observation

3, 6, 9, 12, 15 and 18 months after enrolment
Change in work satisfaction
Tijdsspanne: Between baseline and 3, 6, 9, 12, 15 and 18 months after enrolment

Proportion of sew-ers who state they are satisfied or very satisfied with work, feel valued or very valued at work, and are likely or very likely to stay with Shahi

Between baseline and 3, 6, 9, 12, 15 and 18 months after enrolment
Change in feeling valued-at-work
Tijdsspanne: Between baseline and 3, 6, 9, 12, 15 and 18 months after enrolment

Proportion of sew-ers who state they feel valued or very valued working at Shahi

Between baseline and 3, 6, 9, 12, 15 and 18 months after enrolment
Change in likeliness to stay at work
Tijdsspanne: Between baseline and 3, 6, 9, 12, 15 and 18 months after enrolment

Proportion of sew-ers who state they are likely or very likely to stay with Shahi

Between baseline and 3, 6, 9, 12, 15 and 18 months after enrolment
Change in work efficiency
Tijdsspanne: Between baseline and 3, 6, 9, 12, 15 and 18 months after enrolment

Self-assessed productivity scores using the Cantril's Ladder, with the best possible score being a 10, and the worst being a 0.

Between baseline and 3, 6, 9, 12, 15 and 18 months after enrolment
Attitudes towards vision correction
Tijdsspanne: At month 0

Worker's self-reported attitudes towards vision correction

At month 0
Access to local eyecare services
Tijdsspanne: At month 0

Worker's self-reported access to local eyecare services

At month 0
History of uptake of eyecare services
Tijdsspanne: At month 0

Worker's self-reported history of uptake of eyecare services

At month 0
Change in Quality of Life as assessed by the THRIVE Near Vision Quality of Life tool
Tijdsspanne: Between baseline and endline at 18 months

Self-reported quality of life scores measured with the modified THRIVE Near Vision Quality of Life tool, a Likert Scale ranging from 1 (least affected) to 5 (worst affected).

Between baseline and endline at 18 months
Reasons leaving employment at Shahi
Tijdsspanne: 2 months within participants leaving employment

Reasons given by the former supervisor and colleagues of former sew-ers for workers no longer being employed at Shahi

2 months within participants leaving employment
Change in work productivity
Tijdsspanne: Between baseline and 3, 6, 9, 12, 15 and 18 months after enrolment

Proportion of target production realized by a worker per unit time.

Between baseline and 3, 6, 9, 12, 15 and 18 months after enrolment
Cost effectiveness of intervention
Tijdsspanne: At study closeout at 18 months

Ratio of incremental program cost to additional workers in the intervention group who retain employment vs. those in the control group. Incremental cost is the difference of program costs between implementation of intervention and control (not including study costs, such as data collection).

At study closeout at 18 months
Change in skill grade
Tijdsspanne: Between baseline and endline at 18 months

Worker's skill grade as reported by supervisor.

Between baseline and endline at 18 months
Change in monthly wage
Tijdsspanne: Between baseline and endline at 18 months

Worker's monthly wage as reported by supervisor.

Between baseline and endline at 18 months

Medewerkers en onderzoekers

Hier vindt u mensen en organisaties die betrokken zijn bij dit onderzoek.

Sponsor

Medewerkers

Onderzoekers

  • Hoofdonderzoeker: Nathan G Congdon, MD, MPH, Queen's University, Belfast

Studie record data

Deze datums volgen de voortgang van het onderzoeksdossier en de samenvatting van de ingediende resultaten bij ClinicalTrials.gov. Studieverslagen en gerapporteerde resultaten worden beoordeeld door de National Library of Medicine (NLM) om er zeker van te zijn dat ze voldoen aan specifieke kwaliteitscontrolenormen voordat ze op de openbare website worden geplaatst.

Bestudeer belangrijke data

Studie start (Werkelijk)

21 mei 2022

Primaire voltooiing (Werkelijk)

30 december 2024

Studie voltooiing (Werkelijk)

30 december 2024

Studieregistratiedata

Eerst ingediend

21 oktober 2020

Eerst ingediend dat voldeed aan de QC-criteria

1 december 2020

Eerst geplaatst (Werkelijk)

4 december 2020

Updates van studierecords

Laatste update geplaatst (Werkelijk)

4 november 2026

Laatste update ingediend die voldeed aan QC-criteria

3 november 2026

Laatst geverifieerd

1 augustus 2026

Meer informatie

Termen gerelateerd aan deze studie

Andere studie-ID-nummers

  • MHLS 20_84

Informatie over medicijnen en apparaten, studiedocumenten

Bestudeert een door de Amerikaanse FDA gereguleerd geneesmiddel

Nee

Bestudeert een door de Amerikaanse FDA gereguleerd apparaatproduct

Nee

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