The U.S. Food and Drug Administration found that the advertisements and promotional materials did not offer consumers adequate information about risks and possible side effects.

Warning letters were sent to certain eyecare centers in Indiana, California, Florida, Texas and Georgia.

"Providers whose advertising does not provide adequate risk information are finding out today that the FDA is serious about consumer protection," said Steve Silverman, compliance director at FDA's Center for Devices and Radiological Health in a statement posted on the agency's website.

Surgery with refractive lasers is intended to reduce the need for glasses or contact lenses. It involves the removal of corneal tissue by a special laser and permanently reshapes the cornea and changes its focusing power.

The most common risks of LASIK surgery include dry eyes, the possible continued need for glasses, visual disturbances such as halos, starbursts or double vision, and even loss of vision.

The FDA said it issued letters in 2009 and 2011 to eyecare professionals across the country explaining the agency's concerns about improper advertising and promotion of FDA-approved lasers.

It also issued letters in March 2012 to the American Society of Cataract and Refractive Surgery and the American Academy of Ophthalmology, providing additional information about disclosing risk in eyecare professionals' advertisements and promotional materials.

"The FDA reminds consumers that eye surgery such as lasik is irreversible, that not all patients will achieve optimal results, and that some patients may need additional procedures," the FDA said.

(Reporting by Toni Clarke in Boston; editing by Matthew Lewis)

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