Effects of Near Vision Spectacle Correction on Work Productivity Among Textile Factory Workers in India
Effects of Near Vision Spectacle Correction on Work Productivity Among Textile Factory Workers in India
The investigators will conduct a randomized-controlled trial. The participants will be textile workers aged 35 years and above with uncorrected presbyopia who are employed by a single Indian garment manufacturer - employed by Shahi Exports Private Limited, Karnataka, India - at facilities equipped to measure individual productivity. PROSPER II will assess the impact of free reading glasses on productivity for workers in a textile factory.
Globally, 3 billion people do not have the eyeglasses they need to earn, learn, travel safely in traffic and participate in civic life. Among these, 1.1 billion people lack a simple pair of reading glasses to correct impaired near vision, called presbyopia. Presbyopia, the essentially universal decline in unaided near vision that occurs with aging, is the world's most common cause of vision impairment. Loss of accommodation (ability to change focus from distance to near) due to 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.
Study Plan: This is a randomized trial designed to assess the impact of free spectacles on workplace productivity among Indian textile workers.
Research question: Will providing free glasses to presbyopic Indian textile workers increase work productivity?
Design: Investigator-masked, multi-center randomized controlled trial
Rationale: Although presbyopia is safely, effectively and inexpensively treated with glasses, rates of optical correction in LMICs are as low as 10%. 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. 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). The largest reported effect sizes among such trials 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 (21.6%) compared to those in the control group. Costs were low, over half of pickers aged >= 40 years met criteria to receive glasses, and wearing compliance reached nearly 90%. There is interest to understand if these results from the agricultural setting can be extended to other financially-important sectors.
Methods : The investigators will enrol 800 textile workers aged 35 years and above with uncorrected presbyopia who are employed by Shahi Exports Private Limited in Karnataka, India. Eligible participants will be randomly assigned to Intervention and Control Groups (1:1). Intervention group participants will receive free reading glasses within a week of undergoing a vision screening at the factory. Control group participants will receive reading glasses at the end of the assessment period (three months after vision screening).
The main outcome 3 months later will be work productivity; secondary outcomes are change in skill grade, change in monthly wage, participants' adherence with spectacle wear, self-assessed self-efficacy score and change of quality of life scores. The intervention cost-effectiveness will be studied.
Inclusion Criteria:
Exclusion Criteria: