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.