Reading glasses might be one of the best buys in global health.

I have spent a lot of time thinking about this Tumblr post:

Mostly, I think about it while sitting in an optometrist’s office, about to exchange a large amount of money for the ability to see for another couple of years.  But what if I couldn’t exchange money for the ability to see?

The State Of Global Vision Care

According to the WHO, only about half of the people with vision issues around the world are appropriately treated.  Some 800 million people need glasses and will not get them - a full 10% of the world population!

And the burden of untreated eye health issues is extremely unequal.  Most people with poor vision in rich countries will receive treatment; most people in poor countries will not; 90% of the people with untreated eye issues live in low and middle income countries.

Perhaps this isn’t all that surprising.  When healthcare is hard to access, eye care is even harder to access.  National health care systems often consider vision separate from other kinds of health, so vision is rarely incorporated into national plans.

Relatively few people have regular eye exams, because optometrists are rare outside of rich countries.  On average, a high income country like the US has 78 times as many optometrists per 100,000 population than a country in sub-Saharan Africa.

Furthermore, most people in low income countries live in rural areas, far from the nearest optometrist or optical store.  The most common type of medical provider is a community health worker (CHW).  A CHW is generally someone without a medical degree, but with some medical training.  A CHW who makes it to a village in rural Kenya will ask about malaria, about diarrhea, about pregnancy and childbirth - but vision is simply not in their remit.

But eye care really is essential, perhaps as essential as some of those services.  Vision problems are very common; some 25% of the entire population has some kind of vision issue.

Indeed, if you live long enough, you are essentially guaranteed to develop vision issues.  Developing presbyopia (farsightedness) is considered just a normal part of aging, because the lens in your eye becomes less flexible with age.  There is no way to prevent it; if you are still alive at age 50, you’re going to find reading things up close more difficult.  And indeed, some 500 million people worldwide have untreated presbyopia.  It is the most common form of vision issue, considerably more common (on a global scale) than nearsightedness.¹

Thankfully, presbyopia is very easy to treat by wearing reading glasses.  Unlike nearsightedness, where there’s a wide range of possible prescriptions and you probably do need to see a medical professional, you can determine what reading glasses are best for you by trying on a few with different prescriptions, and seeing what works best.  That’s why you don’t need to see a doctor to get reading glasses in most rich countries - you can go to the drug store, spend $10, and you’re set.

But if you live in rural Kenya and the nearest place that sells reading glasses is in Nairobi?  You may be out of luck.  You can take time away from your job and your family and travel hours (if not days) to Nairobi, spending a considerable portion of your monthly wage just to get there.  And then buying the glasses is yet another upfront cost; you have to hope that once you have them, the glasses will be worth it.  And maybe you don’t have the money and the time right now, so you live with it.

Sure, maybe you can’t see as clearly as you once did, but that’s just the way life is.

Are Glasses That Valuable?

It doesn’t have to be - and it shouldn’t be.  In recent years, two major randomized control trials distributed reading glasses in developing countries.  Both found extremely large impacts on productivity and income.

Assam

In 2017, a team affiliated with the charity VisionSpring distributed reading glasses to tea pickers workers over 40 in Assam.  Tea pickers are paid based on how quickly and accurately they can pick tea leaves off the plants.  With glasses, their productivity (and income) increased 21%.  Perhaps unsurprisingly, 95% of those who received glasses said they’d buy another pair if theirs ever broke.²

Bangladesh

Another study distributed glasses to people with presbyopia in Bangladesh.  These people worked in a variety of occupations - farming, weaving, selling food - but all reported they needed to look at things that were close up at least some of the time.³

Eight months later, the participants that received glasses had incomes 33.4% higher than those that did not.  The glasses more than paid for themselves; getting a $10 pair of glasses increased earnings by $11.80 every month.  If the glasses last a year, workers would expect to earn $141.60 more because of their $10 glasses.

These are very large income and productivity increases.  Going to school for another year only raises your income (on average) about 9%; simply using reading glasses raised incomes as much as if everyone had gone to school for three more years.  And reading glasses are definitely cheaper to provide than three more years of school.

Will We Fix The Vision Care Gap?

A few global development funders have taken notice.  GiveWell and the Livelihood Impact Fund have funded another trial distributing reading glasses, this time in India and Kenya.⁴  But they are the exception, not the rule.

The amount of funding addressing this massive global problem remains relatively small in comparison to the problem, though.  The unfilled need for reading glasses alone is something like $5B.  And one of the largest NGOs in the field, VisionSpring, took in just $20M last year.  Another NGO is targeting getting glasses to 250M million people in the next ten years - but so far, their budget only suffices to distribute fewer than 400,000 pairs a year.  At that rate, they will miss their target by an order of magnitude.

So what is to be done?  Well, funding so far has come from relatively small actors in the global development space.  Governments and aid agencies need to wake up the idea that vision matters to productivity.

Funding glasses distribution could be one of the highest impact things an aid agency does.  Most development interventions are considered “good buys” (for donors or governments) if they return $15 in social benefits for every $1 spent.  Every $1 spent on reading glasses could result in $46 more in earnings.  That’s not a good buy; that’s a best buy - maybe one of the best buys in global health.  More funders should make that buy.

Extra thank yous to Steve Newman, Denise Melchin, and Rob Tracinski, who reviewed this draft on short notice.

1. Which is probably the vision issue you think of when you think of vision issues.  Myopia is nearsightedness and is the kind of vision issue where you have to wear glasses all the time. It is also considerably harder and more expensive to treat than farsightedness.

2.  Indeed, this suggests that efforts to distribute reading glasses could be self-sustaining - that charities would only need to distribute glasses once; after that, people would be willing to travel to the city in order to buy another.

3. Though I am hard-pressed to think of a job where you don’t.

4. For the EAs in the audience: yes, this means that GiveWell thinks reading glasses distribution might be as cost-effective as their top charities.