A county-level city of under a million people in Jiangsu makes about half the world's eyeglass lenses. The local boast is barely an exaggeration: of any two people on Earth wearing prescription glasses, the lenses for one of them very likely came from here.
There is a saying in the trade: of every two people in the world who wear prescription glasses, one looks through a lens made in Danyang. The numbers back it up. This single county-level city, with a population under a million, turns out somewhere between 400 and 800 million pairs of lenses a year, roughly half the world's output and about three-quarters of China's. It is the largest spectacle-lens production base on Earth and the largest eyewear distribution hub in Asia.
Danyang had no optical tradition. The industry began in the 1960s, when educated youth (知青) who had worked in glasses factories in Suzhou and Shanghai were sent down to the Danyang countryside and, with their know-how, helped local people set up small lens-grinding workshops. As schooling spread and television entered every home, myopia rose and demand for glasses surged. By 1987 the county already had more than 400 optical factories.
Early Danyang made glass lenses; the world moved to lighter resin, and for years the raw materials and the coating machines were controlled by foreign firms, keeping Danyang stuck at the cheap end. The turning point was home-grown R&D. Working with a Nanjing university, the local maker Mingyue developed its own resin formulations around 2007 and cut the cost of the material to roughly a third of the imported price; another Danyang firm built China's first domestic lens-coating machine in 2014. The cluster climbed the value chain.
What makes Danyang a cluster town is that the industry is the place, not any one firm. More than 1,600 enterprises and over 50,000 people work in eyewear here, gathered around the China Glasses City and International Optical Center opposite the railway station. A buyer can walk in and compare hundreds of makers in a day; a European optician's custom prescription is transmitted to a Danyang supplier and shipped back inside a week, and the city fields over 15 million custom international orders a year. No single company is the moat. The dense web of competitors is.
China has a second "lens city," and it is Danyang's mirror image. Where Danyang makes 镜片, the lenses for glasses, across a swarm of small competitors, Yuyao makes 镜头, the lenses for cameras and phones, and makes them almost entirely inside one giant company, Sunny Optical. Same word in English, opposite kind of place: the cluster town versus the anchor-company town.