SHANGHAI, China — You surely will need good eyesight to find Shanghai's underground eyeglasses market.

It's near the city's main train station, where masses of people wait in long lines and carry bundles so large you wonder whether they're catching the last train off Earth before destruction comes.

Visit this area on a weekend or holiday and you'll think all of China has come to this square to jostle you and cram the narrow sidewalks and eat at the KFC across the street. The crowds are so bad that police have resorted to holding ropes across crosswalks when the light turns red so that jaywalkers don't stop traffic.

It's a shame the market's so hard to find because it's a Four Eyes' dream. Dozens of independent shops line the underground hallways near the No. 3 exit of Shanghai's 3 and 4 subway lines. They sell plastic, metal and rimless frames of all shapes and sizes, and offer an array of machines that will measure your eyesight and tell you just how blind you are.

Best of all, a pair of prescription glasses will set you back for less than $20, depending on your bargaining skills and your style sense.

There are lots of things for sale on the streets of Shanghai that we don't normally see: live ducks, police sirens, books of Mao quotations. But inexpensive eyeglasses are the one thing I saw that I fervently wish we had in America.

It might seem risky to trust eyewear from a country that also brought us melamine in milk, poisoned pet food and lead jewelry for little girls, especially when the prices are so low. But most of the stores in the market show you how they make eyeglasses, every step of the way.

From the outside, a banner above an alley reads, "Shanghai Sanye Wholesale Market of Eyeglasses." Go down a twisting stairway, and the small eyeglass stores are lined neatly in rows. It seemed quintessentially Shanghai: hip and fashion conscious but hidden underneath a chaotic, crowded place.

Store owners called out to me, offering designer names, so I decided to go into the first shop that ignored me, Li Da Glasses.

I described what I wanted: a pair of brown, plastic frames, and the clerk, Wen-Wen, started opening drawers, pulling out models from behind walls and under cabinets I hadn't even seen. She had Coach, Gucci, Burberry, Ray-Ban and even Playboy (although it might not be a great idea to buy frames from a brand that also makes shot glasses).

I picked out a pair, and the bidding began. Wen-Wen said it would cost 180 yuan, which is about $27. I told her I knew a friend who had gotten them for 90. She offered 150. I went up to 100. We settled on 120, or about $17.

Next, a machine tested my prescription; all I had to do was peer into it. It was the same prescription I had paid $80 for at an eye doctor's office.

To make sure the prescription was right, an employee named Zhong had me put on test glasses and read from a chart.

"Very good! Good! Beautiful!" he exclaimed as I got them right.

I watched as an employee made the lenses in another corner of the store popped them into the frames and put them on me. I saw as clearly as I had since I first arrived in China.