Glasses boost garment worker productivity by 6%, finds new study at Shahi

21 July 2026: A randomised controlled trial at Shahi Exports found that giving near-vision glasses to workers with presbyopia raised productivity by 5.7% over 12 weeks. The PROSPER II study was conducted in Karnataka and published in the British Journal of Ophthalmology in 2026.

Researchers screened 3,648 workers and enrolled 682 sewing machine operators aged 35 or older with uncorrected presbyopia. They assigned 344 workers to receive glasses at the start of the trial and 338 to acontrol group that received identical glasses after the study period.

Presbyopia is an age-related loss of near vision. It can make close work such as stitching and garment inspection harder. The trial measured output using Shahi’s production records rather than supervisor estimates.

The adjusted primary analysis found a 5.7% productivity rise among workers who received glasses, compared with the control group. Self-reported visual function was also better at 12 weeks. Glasses use among the intervention group rose from 41.1% after four weeks to 65% after 12 weeks, an increase of 23.9 percentage points.

Low Cost, Measurable Return

The glasses programme cost USD 9.88 per worker. The researchers estimated that the factory’s gains from higher output exceeded the cost by 337% during the 12-week trial. If the gains continued for a year, the annual productivity benefit would be about USD 162 per worker.

Achyuta Adhvaryu, co-founder of Good Business Lab, said correcting a basic vision problem can benefit workers and employers. The productivity effect was close to that reported for some training and management programmes, but the glasses cost far less.

Shahi Plans Wider Rollout

Shahi Exports plans to extend vision screening and correction across its factories, with a target of reaching more than 100,000 workers. Anant Ahuja, director of ESG and sustainability at Shahi Exports, said the company is extending the benefit to workers across its operations. A summary by DRIVE estimated that applying the same productivity gain across the global garment workforce could add about USD 27 billion in annual output.

www.shahi.co.in