Economic history—the study of economic phenomena, processes, and patterns in past time, employing tools from economics, history, and other disciplines—is a small field. For a brief time, roughly half a century ago, it was a hot area of scholarly interest, but from the 1970s until the early twenty-first century its fortunes ebbed, as historians gravitated to trendier fields such as cultural history and economists moved increasingly toward modeling. The recession of 2007–09 and its aftershocks helped to spark a modest uptick in interest in economic history in both history and economics departments, but mostly in the former, as scholars looked to the past (particularly the Great Depression) for lessons about how and why significant economic downturns arise, how to respond to them, and how to prevent them going forward. A second reason for the renewed interest in history was a seeming rise in economic inequality in the US and elsewhere in recent decades, which prompted some scholars to study income and wealth distributions in the past and others to “interrogate” the capitalist economic system, which they already believed at least implicitly, to have been responsible for economic inequality both historically and in the present day.

In principle, the growing interest in economic history, however modest, should have been a salutary development. In some cases, it in fact was. Generally speaking, though, the results thus far have proven disappointing. Most of the growth has occurred in history departments rather than in economics departments, with many of the practitioners eager critics of capitalism bereft of basic familiarity with—much less command of—analytical tools essential to economic history as it has developed over time, particularly knowledge of economic theory and formal methods. The fact that many of these practitioners—sometimes known as new historians of capitalism—are also unfamiliar with much of the relevant work in economic history produced since the late 1950s (when the field took a turn toward more analytical rigor) has limited the usefulness of their findings as well. Thus, while it’s nice that economic history has been getting more attention of late, further developments will still be needed—a broader understanding of economics by historians and more fruitful interactions between economists and historians, for starters—before the field realizes its considerable potential both within history and economics departments and without.

Regarding broader constituencies: It is painfully obvious today that meaningful appreciation of the economic past is still lacking in many circles. This deficiency at once invites and helps to explain interpretive problems not only for social scientists but also for people in other, “harder” fields as well. A recent, highly publicized study of the economic effects of untreated presbyopia—the age-related inability to focus on nearby objects—in developing countries illustrates this point.

This study, published in PLOS ONE and immediately picked up by the New York Times (“Glasses Improve Income, Not Just Eyesight”) among other major media venues involved a randomized controlled trial or RCT—the gold standard of scientific field research—relating to presbyopia in rural Bangladesh. The researchers involved correctly viewed presbyopia as both a medical condition and a potential drag on the Bangladeshi economy and wanted to see how much effect, if any, a simple, inexpensive intervention would have on that drag. Clearly, such a study could have major implications for both public health and economic development in less developed countries (LDCs) today.

Regarding research design: Setting technical details aside, the key subjects of the investigation comprised over 800 older Bangladeshi workers (aged 40-65), people in “near vision intensive jobs” of various kinds—people working as “tailors, artisans, mechanics, carpenters, farmers, and shopkeepers.” Participants accepted into the trials had to meet a number of criteria, including normal or near normal uncorrected distance visual acuity and evidence of uncorrected presbyopia. Accepted participants were randomly divided into two groups, one of which received inexpensive reading glasses to improve near vision, while the other did not. At the time of division, there was no appreciable difference in the median monthly incomes of the participants. The principal finding from the careful study was that eight months later, the self-reported median average monthly income of the participants in “near vision intensive jobs” who had been given free reading glasses and used them was about 33 percent higher than the participants in “near vision intensive jobs” who had not been subject to the “intervention,” i.e., had not been given free reading gasses to use in the workplace. In other words, near-vision glasses improved both the vision and the income of Bangladeshi workers in near-vision-intensive jobs. Good to know. Hear, hear!

That said, had the researchers—and the news media—been a bit more conversant with, ahem, economic history, the results of the study might not have been viewed as “stop the presses” material, but rather more as useful contemporary corroboration and calibration of effects long known about, at least in a general way. For example, in his monumental 1998 study, The Wealth and Poverty of Nations: Why Some Are So Rich and Some So Poor, the great Harvard-based economic historian David S. Landes included a section on “eyeglasses” in his chapter on the genius of Western innovation in a period in which the West in certain ways resembled LDCs today. In the section, he writes that the invention of [magnifying] spectacles in the medieval period “more than doubled the working life of skilled craftsmen, especially those who did fine jobs: scribes (crucial before the invention of printing) and readers, instrument and toolmakers, close weavers, metal workers.”

As Landes correctly framed things: “The problem [was] biological: because the crystalline lens of the human eye hardens around the age of forty, it produces a condition similar to farsightedness (presbyopia). The eye can no longer focus on close objects. But around the age of forty, a medieval craftsman could reasonably expect to live and work another twenty years, the best years of his working life—if he could see well enough. Eyeglasses solved the problem.”

Landes then goes on to lay out the history of eyeglasses. In so doing, he points out that although rudimentary magnifying glasses and crystals had been developed earlier in a variety of places (and used for reading), the first functional magnifiers—with reduced distortion and connected to a wearable device (“thus leaving the hands free”)—seem to have been developed in Pisa in what is now Italy toward the end of the thirteenth century.

And this was only the beginning, according to Landes. Over the next century and a half, the Italians refined the optical arts considerably, making a variety of convex and concave lenses for diverse eye conditions. He maintains that Europe “enjoyed a monopoly of corrective lenses for three to four hundred years.” He goes on to argue that eyeglasses not only made “fine work” possible, including the manufacturing of fine instruments over a lengthier period of time, but also encouraged the development of other “fine” technologies—”gauges, micrometers, and fine wheel cutters”—that over the centuries helped Europe and the West to move ahead of other areas in the development of a “battery of tools linked to precision measurement and control,” areas increasingly vital to economic productivity. To be sure, Landes may have been a bit too focused on technology in the West—devoting less attention to relevant developments in China, South Asia, and the Arab world—but for our purposes here the main takeaway is not necessarily the uniqueness of the West, but the fact that “near vision” spectacles go way back, with their economic importance long a well-established historical fact.

So while the results of the RCT recently conducted in Bangladesh—and a few other similar studies conducted elsewhere—are important and merit praise, greater knowledge of and appreciation for economic history would have both helped the researchers in framing the problems to be studied and allowed the public better to contextualize the findings achieved. No need, then, for any of us to be gobsmacked.