OTHER VISION CORRECTION PROCEDURES
CONTACT LENS IMPLANTS
A contact lens implant may correct either extreme nearsightedness or extreme farsightedness. Unlike with cataract surgery, the natural lens is not removed; rather, the implant sits in front of the natural lens. In effect, the contact lens implant becomes an internal contact lens.
Implantable contact lens technology has arisen out of the advances in modern cataract surgery. Current technology allows ophthalmologists to insert flexible intraocular lenses (used to replace the natural lens after cataract surgery) through extremely small incisions. Some contact lens implants, too, are flexible enough to allow folding as they are inserted through small incision openings.
Because of the slightly increased risk of more serious complications, contact lens implants are reserved for high amounts of nearsightedness or farsightedness-beyond the safe limits of LASIK. These lenses are typically reserved for patients with myopia greater than 9 to 10 diopters and hyperopia greater than 4 diopters. In addition, contact lens implants may be preferable to LASIK in patients who fall within the safe LASIK parameters with regard to their prescription but who have thinner corneas, making the tissue-removal aspect of LASIK less desirable. These lenses are implanted one eye at a time in an outpatient procedure that takes ten to twenty-five minutes.
Implantable contact lenses are very safe. Risks unique to contact lens implants include causing a cataract, damage to the inner layer of the cornea, or an infection in the eye. Such complications are very rare. In large FDA studies of these lenses with thousands of patients treated, no patient lost vision from these lenses. Other risks are similar to those of LASIK and PRK: undercorrection, overcorrection, and nighttime glare. Undercorrections and overcorrections can often be treated with a LASIK enhancement, because the remaining correction is usually very small.
Advantages of the implantable contact lenses include a more accurate correction and better night vision than with LASIK or PRK. Also, these lenses are removable if for any reason a patient is unsatisfied with his or her vision. After the implants are removed, vision returns to where it was before surgery.
Relatively few surgeons today have the experience to implant these lenses, but more and more surgeons are learning the procedure. We expect it to become widely available in the next five to ten years.
Bioptics
