LASIK is the acronym for Laser-Assisted In Situ Keratomileusis and is an eye surgical system that permanently corrects vision by removing a thin layer of the cornea. This procedure works best on patients with moderate to high degrees of myopia (nearsightedness), low to moderate degrees of hyperopia (farsightedness), and astigmatism associated with myopia, and who have thick corneas. It is the most well-known surgical vision correction method.
People with normal eyesight see objects clearly because images are brought into a correct focal point by the cornea and lens of the eye. Ideally, the cornea’s curvature is evenly matched to its length in a normal eye. People with astigmatism, myopia or hyperopia have irregularly shaped corneas, so the objects seen are not focused properly. LASIK changes corneal shape by precise removal of corneal tissue, and by doing so corrects the eyes’ focusing power.
There are, however, risks to LASIK eye surgery.
There is a remote chance of complete loss of vision. If this happens, it is usually because the patient had a pre-existing condition which should have precluded the surgery in the first place, such as pregnancy, cataracts, arthritis, diabetes, glaucoma, or lupus. People with large pupils are also poor candidates for LASIK. Dry eye syndrome will be aggravated by this procedure.
A few patients complain that they permanently see “ghost” images, have blurred vision, diminished contrast, and bad night vision. When LASIK was first introduced, 5% of patients had post-operative complaints; however, refinements in the procedure have caused this rate to drop to less than 1% if LASIK is performed by skilled practitioners and patients are properly screened prior to surgery. If problems do occur, they can often be resolved by retreatment.
FDA has approved LASIK laser eye surgery since 1998. While there are a lot of satisfied patients, there are however no long-term studies about its effects. Realize the limitations and the risks of LASIK eye surgery before you sign up for the procedure.
Though less well known, these small implants can improve vision in patients with mild to moderate myopia without the risk of permanent eye damage inherent in the tissue removal technique of LASIK. Intacs are semi-circular disks implanted in the cornea which stretch it to assume a flatter shape. Though slightly less precise than LASIK, they are removable and replaceable, so if the patient has an unexpected over- or under-correction, the implant can be removed and another of a different size inserted to obtain the desired correction. The implants are located at the edge of the cornea, so the central visual area is completely intact and undamaged, and the strength of the cornea is undiminished, making it a better option for pilots and those who engage in contact sports where eye injury is a possibility.
Intacs are unsuitable for severe myopia and more than minor astigmatism (1.00 diopters), as the cornea can only be stretched so far. If the Intacs are removed, vision returns to its preoperative level. Aside from vision correction, Intacs are also used to treat keratoconus.
Intacs are FDA approved and 10-year studies have revealed no major problems with Intacs and very few patient complaints; however, because the procedure takes more training than LASIK, there are fewer eye surgery clinics offering it. However, the Intacs website gives a list of practitioners in each state, as well as a few in Canada, Europe, and Mexico.
Because many people do not want to risk LASIK and Intacs cannot help those with severe vision problems, intraocular lens implants (IOL) are a new option approved by the FDA in 2004 to correct moderate to severe nearsightedness. The Artisan lens, manufactured by Ophtec, is similar to the type of lens implant utilized to restore vision following cataract eye surgery.
The new IOL, called the Artisan, is intended for only patients who have 2.5 diopters or less of astigmatism.
The artificial lens does not replace the natural lens but is inserted in front of it. The main problem found with the implant was the steady loss of endothelial cells in the corneas of patients who received the implants. The endothelium is a layer of cells that line the undersurface of the cornea and are essential in keeping the cornea clear. A three-year study showed a continual steady loss of endothelial cells of 1.8 percent a year. At this point, no one can predict whether this loss will proceed at the same rate indefinitely or even its impact on corneal function.
To minimize the long-term effects of the device on the corneal endothelium, the FDA is requiring that the new lenses be labeled to specify that they should only be implanted in patients whose corneal endothelial cells are thick enough to withstand minor cell loss.
More serious complications were few: retinal detachment (0.6%), cataract development (0.6%), and corneal swelling (0.4%). The FDA is requiring Ophtec to conduct a five-year follow-up survey of its implant patients to better assess the post-surgical incidence of cataract development, retinal detachment, and other ophthalmic diseases.
The Artisan lens is intended to be a permanent implant. Though it can be removed surgically, vision may not always return to what it was prior to getting the lens. Because it does not affect astigmatism, patients with this problem might still require glasses.