Studies of corneal rings showed they can be adjusted or removed without adverse affects. On the other hand, the rings can only help those patients whose nearsightedness falls within minus one to minus three diopters, or optical measurement units. Those who are more severely nearsighted, farsighted or have an astigmatism caused by irregularly curved corneas, may have to wait several years before corneal rings are available to them. For those who can consider corneal implants now, Sugar says, the operation is a relatively simple one performed on an outpatient basis. It does require some technical skill, and it requires anesthesia in the form of eye drops.
Recovery is rapid - patients are usually back to work the next day.
So, Sugar says, patients who might be interested in the implants should consult with their eye doctors before deciding which optical option to choose. An estimated 68 million Americans are nearsighted, about 20 million with a mild form. No procedure is 100 percent predictable, so some patients may sometimes need glasses. Corneal rings are made of the same material used for years in some intraocular lenses to treat cataracts.