A simple exercise of providing spectacles to tea workers in Assam, who had near vision, proved effective as it helped them pluck more leaves, leading to a rise in their incomes. The PROSPER (Productivity Study of Presbyopia Elimination in Rural-dwellers) study conducted in Assam, which was published on July 23 in The Lancet Global Health, showed that a simple pair of presbyopic glasses in tea workers (mainly women) in India improved their productivity by more than 20 per cent.
The main researcher of the study, Priya Adhisesha Reddy, along with Parikshit Gogate, Coordinator at Community Eye Care Foundation, Prof Nathan Congdon at Centre for public health, Royal Victoria Hospital, UK, Graeme MacKenzie —- and others conducted a randomised trial in tea pickers, who were above 40 years in Assam with and had near visual acuity.
Dr Gogate told The Indian Express that the findings of the study suggest that the provision of glasses might be sufficient to prevent older workers from leaving the labour force due to age-related vision loss.
Reddy, who is attached to Aravind Eye Hospital, a post-graduate institute of opthalmology in Pondicherry, said that age-related decline in near vision or presbyopia is the most common cause of vision impairment globally, but no trials have assessed its workplace effects.
While 2,699 permanent tea pickers at the three estates were identified, a total of 1,297 completed the eye examination. Based on the examination, 751 workers were eligible for the trial, of which 376 participants were allocated to the intervention group and 375 to the control group. Glasses were distributed in the intervention group as part of the study conducted last year by the Lions National Association of the Blind (NAB) Eye Hospital (Miraj, India) and Queen’s University Belfast.
There was a significant increase in relative productivity of more than 20 per cent among intervention-group members, the study researchers said. The daily weight of tea picked in the intervention group increased from 25 kg per day to 34·8 kg per day between the baseline and the evaluation periods. This increase of 9·84 kg per day was greater than that for the control group (from 26 kg per day to 30·6 kg per day, an increase of 4·59 kg per day, researchers explained.
Unlike the rest of the year, the amount of tea leaves picked during the high season in Assam (June to October) is limited by the worker, rather than by the rate of plant growth.
Presbyopia is the most common cause of vision impairment globally, but no trials have assessed its workplace effects. Current global estimates show that approximately 1·1 billion people are affected by presbyopia, nearly a third of whom are 50 years or older.
From crude data available, the prevalence of presbyopia is estimated to be 35·6 per cent in people aged 35 years and older and increases to 40·3 per cent for people aged 50 years and older.
More than 90 per cent of these individuals are in developing countries, Reddy added.
Income is hence tied to productivity as an incentive, Gogate explained.
Presbyopia is associated with difficulty in daily living activities, especially for those in professions demanding a keen eyesight for activities such as reading, writing, weaving, and others and affects quality of life, both in the developed and developing world, and has a huge impact on productivity, Reddy said.