Laser eye surgery remains controversial in China due to uncertainty over long-term side effects. But its popularity is growing as evidenced by the number of hospitals competing for eye patients.

More than 400 million people suffer from shortsightedness, which tops the world, the General Administration of Sports said in 2009.

About 700,000 people in China choose laser surgery to improve their vision each year.

"We indeed have this problem of over commercialization," Chang Zheng, a member of the Chinese Ophthalmologic Society and director of ophthalmology department at AIER Eye Hospital in Guangzhou, told the Global Times Sunday, the 15th Eye Care Day.

"It's medical surgery after all," Chang said.

Although there are other ways to correct vision, LASIK is the most common. It is a surgical procedure that uses an excimer laser to permanently change the shape of the cornea to correct shortsightedness and other vision problems.

LASIK was first introduced to China in 1993 and it has mushroomed in many hospitals. Advertising slogans such as "bid farewell to your spectacles in 30 seconds" are a common sight on billboards and in TV commercials.

Ling Fu, a leading surgeon at AIER Eye Hospital in Chengdu, Sichuan Province, told the Global Times that he previously performed 110 surgeries in a single day. Ling said his hospital has about 7,000 to 8,000 patients a year.

In Zhengzhou, Henan Province, the local media reported earlier that patients "flocked" to eye hospitals during summers, a peak time for surgeries.

"It's like a production line," an unidentified surgeon told local Dahe Health News, adding he performed 180 procedures in one day.

"Unlike other medical surgeries, laser eye surgery mostly relies on machines. The demand for a surgeon's skill is relatively low," Chang said.

He explained that since it's so easy to enter the field, it contributed to a boom in providers.

"As a medical surgery, the market approach towards it has caused many problems including exaggerated advertising and unruly price wars," said Wang Lejin of the No. 3 Hospital of Peking University.

The average cost of the surgery ranges from 4,000 ($585) to 8,000 yuan for two eyes. However, some facilities in Henan promoted it for as low as 900 yuan earlier this year.

Wang said that some hospitals are using used equipment in order to keep prices low, which is risky.

Some hospitals tend to downplay problems from less successful surgeries, including double vision and dry eyes.

"There are barely any side effects," a consultant at AIER Eye Hospital in Chengdu told a caller.

Sixteen experts submitted a proposal to the Ministry of Health calling for measures to manage the wild boom of the surgery.