A surgeon sees his work on a monitor

From Medical Correspondent Dr. Steve Salvatore

NEW YORK (CNN) -- The laser is today's most popular tool for surgically treating nearsightedness and astigmatism. Now the Food and Drug Administration has approved the laser for treatment of farsightedness as well.

The two most popular procedures are called LASIK and PRK, or Photo-Refractive Keratectomy. Both involve reshaping the cornea with a laser, but the techniques are very different.

"In PRK, we use the laser to reshape the cornea directly on top of the cornea," said corneal specialist Dr. Ken Moadel. "With LASIK, the laser is applied underneath the surface of the cornea."

Recovery time for LASIK is shorter and less painful than PRK. But doctors say the right choice really depends on your degree of visual impairment.

"Forgetting pain, forgetting discomfort, patients have better visual outcomes following LASIK for high degrees of nearsightedness," Moadel said.

Patient in laser surgery room

Laser vision correction is extremely popular and the results can be impressive -- in many cases, people can throw away their glasses.

But doctors emphasize the laser procedures are not for everyone. Pregnant women cannot have the procedure done, and there are other concerns.

"Your eye has to be essentially healthy; the cornea has to be a normal shape with no other corneal diseases or other types of eye diseases, like retinal diseases," Moadel said.

"Typically, our patients are 18 and older, and more importantly, your prescription has to be stable," he said.

Laser surgery boasts an extremely high success rate, with only one in every 100 patients developing minor visual problems after surgery.

Corneal ring

But because these changes are permanent, the chance of problems developing leads some people to look for other options, such as corneal rings.

"The ring is an investigational procedure where we put a small piece of plastic into the cornea and that reshapes the cornea," said Dr. George Waring of the Emory Eye Center.

The major difference between the corneal rings and laser surgery is that rings can be taken out.

The corneal rings may be widely available as early next year, and the cost is similar to laser surgery, about $1,500 to $3,000 per eye. However, none of the procedures is usually covered by insurance.