What a difference vision correction can make

Director of research at Orbis International and Ulverscroft chair of global eye health at Queen’s University Belfast, Nathan Congdon (pictured above), discusses the findings and next steps of the PROSPER study

Sight test

What is the PROSPER study?

PROSPER (PROductivity Study of Presbyopia Elimination in Rural-dwellers) is the first-ever randomised controlled trial that has tried to answer the question of whether providing a simple pair of glasses could improve productivity in the workplace in a low-income setting.

Why and how was the study established?

The study came about because of the desire for data to support the important notion that we can reduce poverty with glasses.

This is a study that I have wanted to do for around 10 years – it is not easy to find a place to do a study like this. Therefore, we were lucky to find the perfect setting – a set of tea gardens in India that are run by one of the largest companies in the world, Amalgamated Plantations Private Ltd (APPL). 

APPL was enthusiastic and willing to support us with the study because it wanted to be able to offer the best working conditions for its workers. It provided us with the support and introduction needed, and, crucially, the facilities to measure the amount of tea that the workers were picking every day.

Prior to performing the study, we thought that there would likely be an impact on productivity for those we gave glasses and indeed we found a big impact.

"Of all the vision problems that we deal with, refractive error is the simplest to deal with – we could wipe this problem out in a very simple way. It’s about getting glasses onto people’s faces"

What did the study involve? 

The study ran for three months. The participants were enrolled towards the end of July last year and it ran during high tea season until October. 

Participants were people who have been picking tea for many years, most of whom were women (75%).

APPL had automated systems that measured the tea picked every day, so the measurements could be done while we remained anonymous. During the trial no one knew which women were in the glasses group and which were not as the weighing process was handled by an automated machine.

We also collected baseline data – APPL provided us with data from June of the same year so we could do a comparison on the data collected during the study.

We were anxious to see whether the group who received glasses had a bigger uplift in terms of productivity, and that is what we found. Those who wore glasses picked over 5kg a day more tea than those who were not wearing glasses. It is a huge uplift and therefore had a big impact on their livelihood and income.

Are the findings what you expected?

They were a lot more than we expected. When we initially set the study up, we felt we were being very optimistic by saying we would find a 10% difference in productivity between the two participant groups. In fact, what we found was between a 20–25% increase. Furthermore, among the older workers, the improvement in productivity was well over 30%. That is what we would expect because presbyopia is an ageing condition.

Overall, the large gains were a big surprise for us and the findings exceeded expectations. 

What happens next?

All of us involved in this work are researchers by trade, but all of us are also involved in programmes to put our research findings into action. Therefore, the publication of the findings is just the first step.

One next step is trying to move this work forward to make sure that more and more people have the best vision they can have in the workplace.

Consequently, we would like to move forward with additional research in order to broaden the evidence base. It’s pretty easy when we go to tea and coffee manufacturers with these findings to show how clearly beneficial having vision correction is, but to be able to talk to textile manufacturers and automobile companies, it would be valuable to have real data from their sectors. Therefore, we want to expand the evidence to show that this is not something that just works on the farm, but works in the factory as well.

"It's great to have good results and wonderful to have a nice paper, but my dominant feeling is of enthusiasm and an inpatience to get moving on solving these problems"

We are also keen to show that this can be done in the cheapest, simplest possible way. It was already cheap in the tea setting, it cost under £10 to provide a worker with glasses. But we think that if we train people in factories to be vision ambassadors who can help people select glasses from a set of options, we can probably produce just as good an effect at an even lower price.

We are also interested in a project-related to other ways that vision transforms lives. We are keen to do work on traffic safety to show that providing a pair of spectacles can significantly reduce accident rates for workers who make their living as drivers, for example.

We would also like to expand some of the research that we have done with children. Previously we have published trials that show that providing spectacles to children in rural China significantly improved their academic performance. We would like to take the next step in this research and show that giving spectacles to a child not only improves their grades, but that it makes them more likely to stay in school.

What does success look like in the future?

Success looks like nobody being held back, in the workplace and in school, by having a lack of access to the tools required for good vision. In particular, when we talk about spectacles and refraction, we are talking about something that is so simple. Of all the vision problems that we deal with, refractive error is the simplest – we could wipe this problem out in a very simple way. It’s about getting glasses onto people’s faces.

In a study like PROSPER, where we have shown that visual correction can so significantly improve the productivity and income of these women, we know that investing in this will have an immediate effect on the family and the wellbeing and health of their children and their communities.

How does it feel to achieve this study?

It’s very exciting on a personal level, I think it’s some of the best work that I have done in the sense that we put together a well-done trial under challenging circumstances. But there is also a sense of eagerness to get moving on really doing something with the results. It’s great to have good results and wonderful to have a nice paper, but my dominant feeling is of enthusiasm and an impatience to get moving on solving these problems. 

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