It is 2.30 pm on a Wednesday. Xidan, one of Beijing's largest shopping areas, is swamped with trendy adolescents and 20-somethings all looking for the latest fashion in shoes, clothes and accessories at bargain prices.
Many of them are especially in the hunt for cosmetic contact lenses, a craze that made it to the mainland a few years ago.
The lenses are popular because they enhance the color of the iris, making the eye appear brighter or larger, and in some cases entirely changing its color.
Although unregulated, central authorities last month promised to reclassify the product to ensure those sold on the Chinese market meet strict safety standards in the future.
Until then, however, health experts warn that consumers and traders are largely blind to the risks that shoddy contact lenses pose, and say youngsters are in danger of sacrificing their sight for fashion.
Cosmetic lenses can be bought almost anywhere in China, from trained optometrists to small accessory stores, which offer them alongside nail polish, face glitter and hairclips.
"We have dozens of colors, so you will at least find one suitable for you," said a saleswoman called Zhang at Mingzhu shopping center in Xidan. The most expensive pair at her shop cost 90 yuan (S$18). "The gray and black colors are very popular.
"For a more comfortable feeling, I'd choose a pair priced at more than 60 yuan," she said. "There are cheaper ones, though 30 to 40 yuan. Don't worry, the quality is also OK."
Of course, it is not something she can really guarantee. The packaging for a mid-price pair she handed over as an example was all in Korean and carried no stamp to show it had cleared the Chinese quality supervision authority.
Even optometrist stores do not require a medical checkup before they sell cosmetic lenses, which can also be made to order for shortsighted people.
As Zhang was making her pitch, Xu Yuan, a regular customer, arrived and ordered five pairs of gray and purple lenses. She has been wearing them for about 10 hours a day for the past year.
"I didn't have an eye test (before wearing cosmetic lenses)," said the 20-year-old saleswoman, who also works in Mingzhu mall. "I think they are safe, as I haven't suffered any severe problems. If I feel uncomfortable, I just take them out and let my eyes have a rest for a day or two."
Cosmetic contact lenses may get harder to come by for shoppers like Xu in the coming months.
According to a statement by the State Food and Drug Administration on Jan 19, the fashion accessories have been re-classified as "medical apparatus", the same as corrective lenses.
The decision, made after medical professionals raised concerns over health and safety, means products entering the Chinese market will be subject to regulation.
Although no date has been given for when the new rules will come into effect, the statement advised producers and vendors to cease making or importing cosmetic contact lenses to avoid potential financial losses, as products without the necessary certification will be blocked from sale.
The difference between good and bad lenses is "like night and day", said Lu Yanyun, director of Tongren Hospital's contact lens center in Beijing.
Manufacturers of quality products have devised a way to cushion the colored part of the lens so that it does not put pressure on the eye, she said, warning that people who use inferior varieties are risking their eyesight.
"Poor-quality lenses can scratch or even poke holes in the cornea, which can basically make you go blind," Lu said.
Johnson & Johnson Vision Care, one of the best-selling brands of contact lenses in China, produces two kinds of cosmetic lenses in three "natural" colors. Spokesman Yu Guoxiong said the colored layer of its lenses "doesn't touch the eye directly", while the design ensures permeability.
"Although the changes (by the central government) will have an impact (on the market in China), I think a well-regulated market will encourage more people to choose cosmetic contact lenses," Yu added.
At Bright World Glasses, a Beijing-based chain store, a saleswoman called Li said the brands she sells already meet the standards for medical apparatus.
More than half of the store's customers buy colored lenses, with lenses that replicate an animal's eyes also selling well. "They are priced at about 1,000 yuan a pair," she said. "Cheaper ones have poor permeability and often lose their color."
Even at Bright World Glasses customers do not need eye examinations prior to purchase.
Yet, contact lenses in general greatly increase the risk of infections like pink eye and can deprive the eye of oxygen. Li Zhong at Intech Eye Hospital recommended that users wear products no longer than 10 hours straight. For cosmetic lenses, it should be no more than four hours.
Cheng Yuan, 26, has lived in Britain for five years. There, contact lenses, including cosmetic varieties, cannot be sold without a prescription.
"If you want to buy just ordinary contact lenses for the first time, you have to undergo an eye test first," said the Chinese-language teacher, who lives in Scotland. "They check the health of your eyes and decide whether you can try lenses or not."
At the branch she visited, customers were unable to purchase lenses until after a free trial of at least a week and then a second test to check for side effects.
The final price for a reusable lenses was about 20 pounds ($30), Cheng added, about double what she now pays in China.
Like in the West, cosmetic lenses are also readily available online. This will be another challenge for the central government to overcome in its drive to improve safety standards.
Taobao, China's largest Internet shopping platform, has myriad companies that stock the lenses, including Sasa Optical Store, which offers a range of brands - Eva, Misseye, Cocoeye and Komi-look - not available in large specialist shops.
Using the website's instant messenger, a salesperson told China Daily that the store stocks Chinese products, as well as imports from Japan and South Korea. The cheapest was a pair of lenses costing just 28 yuan that came in more than 20 colors.
When asked whether there were any risks involved, the vendor insisted the lenses are safe as long as the wearer has no history of eye disease.