Providing inexpensive glasses to correct near vision has boosted factory worker productivity by almost 6%, with the intervention delivering a 337% net return on investment over a three-month trial period. Scaling the approach across the industry could generate an additional $27 billion a year for lower-income economies, where the majority of garments are produced.
- One in four sewing machine operators has uncorrected visual impairment, leaving a significant share of the global garment workforce operating below full productive capacity.
- The trial enrolled 682 workers at garment factories in India, randomising participants to receive either corrective glasses or no intervention over a twelve-week observation period.
- Workers who received glasses recorded a statistically significant productivity gain of 5.70% compared with the control group, with all participants completing the full observation period.
- The findings have been reported in 'PROductivity Study of Presbyopia Elimination in gaRment workers (PROSPER II)', published in the British Journal of Ophthalmology.
INSIDE THE TRIAL: The trial was designed as a randomised controlled trial conducted on a factory production line, with participants screened for near vision impairment and allocated to receive either corrective glasses or no intervention. Each pair of glasses cost approximately $10 per worker. The study was conducted by researchers from VisionSpring and Queen's University Belfast, with financial support from USAID.
- Of 4,990 potentially eligible workers, 3,648 (73.1%) underwent eye examinations and 682 (18.7%) were enrolled and randomised to glasses or control groups.
- Enrolled participants had a mean age of 41 years and were 99% female, reflecting the demographic profile of sewing machine operators at the host factories.
- Shahi Exports, India's largest apparel manufacturer, served as the host site, providing free glasses to sewing machine operators experiencing presbyopia, an age-related near vision condition.
- The intervention comprised vision screening, provision of corrective glasses, and encouragement to wear them consistently for the duration of the study.
- Shahi Exports has since announced plans to extend free vision screening across its entire factory workforce, covering all of its facilities.
THE BIGGER PICTURE: The garment industry is operating under significant strain from tariffs, energy prices, and intense competition, conditions that have contributed to large numbers of factory closures. It is within this context that the trial carries particular weight, as it is the first study of its kind conducted in a live manufacturing environment, generating trial-based evidence where none previously existed.
- The absence of reliable trial-based evidence had previously held back vision correction programmes in the garment sector, despite longstanding interest in addressing the issue.
- The investigators concluded that free corrective glasses confer a significant productivity benefit in a factory setting and are substantially less costly than other successful interventions, such as management training.
- The findings carry implications beyond apparel, with ministries of labour in countries with large manufacturing workforces identified as potential drivers of rapid economic growth through workforce vision correction.
- Uncorrected visual impairment affects workers across apparel and footwear manufacturing, sectors that offer unique employment opportunities particularly for rural communities and women.
WHAT THEY SAID
Eyeglasses are one of the simplest and most cost-effective ways to improve productivity in a factory. For factory owners in a highly competitive sector, having a workforce that can see clearly is an essential competitive advantage. Ministries of Labor in countries with large manufacturing workforces, including apparel and footwear, could achieve a rapid injection of economic growth by ensuring all workers see well to do well.
— Ella Gudwin
Chief Executive and Co-author, PROSPER II
VisionSpring
There has been interest for many years in vision programmes for the garment manufacturing industry… but the lack of reliable trial-based evidence that glasses could significantly improve worker productivity has held the field back. PROSPER II now provides that evidence, showing that a simple pair of glasses can improve productivity at a level comparable to far more complex interventions such as management training, at a fraction of the cost per worker.
— Nathan Congdon (Chief Investigator, PROSPER II)
Ulverscroft Chair of Global Eye Health; Director of Research, Orbis International
Queen's University Belfast
