NANJING, July 25 (Xinhua) -- Tang Longbao, 64, has been making glasses for over four decades.

Tang is a native of Danyang in east China's Jiangsu Province, which has been dubbed China's "spectacles city" as there are more than 1,600 companies engaged in the eyewear industry.

Danyang's eyewear industry began in the 1960s when a group of technicians moved there from Shanghai and Suzhou to set up their own companies. Tang joined them and became an apprentice.

"The manufacturing techniques were quite simple. We only had a dozen workers and the quality of the glasses was judged merely in visual inspections by senior opticians," Tang recalled.

Lacking advanced techniques and limited by the planned economy, with resources highly-centralized, Danyang's glasses industry almost died. In 1977, the company Tang worked was on the brink of collapse.

Things turned around just a year later. In 1978, China began its journey of reform and opening-up, which has developed the country into the world's second-largest economy over the last 40 years. The fate of Tang and many others across the county has been completely altered.

"We were free to purchase materials and could sell our products in more places, including department stores," he said.

Sales soon soared but dropped again when imported glasses, which were attractive both in price and quality, began flooding into China. In the mid-1990s, Tang witnessed another wave of bankruptcy among eyewear companies in Danyang.

"Our company had more than 800 staff in 1985, but in 1992, there were only 100," Tang said.

It was in 1992 that Tang took over Situ Lens, the company he had worked at for two decades. To rally business, he invited foreign opticians to improve the quality and workmanship of products and frequently attended global exhibitions to learn from foreign brands and explore new markets.

"Few foreign buyers had ever heard of Danyang in the beginning, some even thought we were frauds," said Tang. "But their opinions began to change after a few years and we started to get some orders. Later, some foreign customers came to seek cooperation with us."

In December 2012, Tang's company and Essilor Group, a French ophthalmic optics company, established a joint venture called Million New Optics Group. It has now grown into a well-known resin lens manufacturer in Asia.

The booming eyewear industry also draws business people from overseas. Kashala Gededn, from the Democratic Republic of the Congo, took up an internship at a glasses company in Danyang this February while pursuing his doctorate in Jiangsu.

"I believe there is big market potential for glasses in Africa. I want to bring more quality Chinese glasses to my homeland," he said.

To maintain its market share and keep up with the new market demand, eyewear companies in Danyang have attached more importance to innovation and branding in recent years.

This June, Danyang Tianlu Eyewear E-commerce Company produced Bluetooth glasses using bone conduction technology -- the same technology that has been used in Google Glass. It allows customers to make phone calls and turn on music by simply pressing a button on the frame.

Sun Guangyi has been working in the eyewear industry in Danyang for 24 years. Last July, he caused a stir in the local eyewear market by inviting glasses designers to his store and offering customized frame designs on the spot.

"The young generation is focused more on fashion, style, and experiences, so we must cater to their demands to develop glasses in line with future trends," Sun said.