PROSPERIII: PROductivity Study of Presbyopia Elimination in Rural-dwellers III
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.
|Condition or Disease||Intervention/Treatment||Phase|
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.
Arms and Interventions
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 (April 2021). 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 (October 2022).
|No Intervention: Control|
Workers assigned to the Control group will receive similar free glasses at the end of the study assessment (18 months).
Primary Outcome Measures
- Work retention [February 2021 to July 2022; 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
Secondary Outcome Measures
- Compliance with spectacle wear [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
- Change in work satisfaction [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
- Change in feeling valued-at-work [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
- Change in likeliness to stay at work [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
- Change in work efficiency [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.
- Attitudes towards vision correction [At month 0]
Worker's self-reported attitudes towards vision correction
- Access to local eyecare services [At month 0]
Worker's self-reported access to local eyecare services
- History of uptake of eyecare services [At month 0]
Worker's self-reported history of uptake of eyecare services
- Change in Quality of Life as assessed by the THRIVE Near Vision Quality of Life tool [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).
- Reasons leaving employment at Shahi [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
- Change in work productivity [Between baseline and 3, 6, 9, 12, 15 and 18 months after enrolment]
Proportion of target production realized by a worker per unit time.
- Cost effectiveness of intervention [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).
- Change in skill grade [Between baseline and endline at 18 months]
Worker's skill grade as reported by supervisor.
- Change in monthly wage [Between baseline and endline at 18 months]
Worker's monthly wage as reported by supervisor.
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 40cm
Employed at the factory for >=3months in the sewing department
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
Contacts and Locations
|1||Centre for Public Health||Belfast||Northern Ireland||United Kingdom||BT12 6BJ|
Sponsors and Collaborators
- Queen's University, Belfast
- Clearly Initiatives
- University of Michigan
- Good Business Lab
- Zhongshan Ophthalmic Center, Sun Yat-sen University
- Principal Investigator: Nathan G Congdon, MD, MPH, Queen's University, Belfast
Study Documents (Full-Text)
- MHLS 20_84