myopia
Article

Eye Surgery
By Frank Hague, Thu Dec 8th

Eye Surgery has become a mainstream method of vision correction,and this article will explain the advantages and disadvantagesof three different methods being offered to the medicalconsumer.

Lasik Eye Surgery. How to cure myopia. How I cured my myopia.

LASIK is the acronym for Laser-Assisted In Situ Keratomileusisand is an eye surgical system which permanently corrects visionby removing a thin layer of the cornea. This procedure worksbest on patients with moderate to high degrees of myopia(nearsightedness), low to moderate degrees of hyperopia(farsightedness) and astigmatism associated with myopia, and whohave thick corneas. It is the most well-known surgical visioncorrection method.

People with normal eye sight see objects clearly because imagesare brought into a correct focal point by the cornea and lens ofthe eye. Ideally, the cornea's curvature is evenly matched toits length in a normal eye. People with astigmatism, orhyperopia have irregularly shaped corneas, so the objects seenare not focused properly. LASIK changes corneal shape by preciseremoval 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 thishappens, it is usually because the patient had a pre-existingcondition which should have precluded the surgery in the firstplace, such as pregnancy, cataracts, arthritis, diabetes,glaucoma, or lupus. People with large pupils are also poorcandidates for LASIK. Dry eye syndrome will be aggravated bythis procedure.

A few patients complain that they permanently see "ghost"images, have blurred vision, diminished contrast and bad nightvision. When LASIK was first introduced, 5% of patients hadpost-operative complaints; however, refinements in the procedurehave caused this rate to drop to less than 1% if LASIK isperformed by skilled practitioners and patients are properlyscreened prior to surgery. If problems do occur, they can oftenbe resoved by a retreatment.

FDA has approved LASIK laser eye surgery since 1998. While thereare a lot of satisfied patients, there are however no long termstudies about its effects. Realize the limitations and the risksof LASIK eye surgery before you sigh up for the procedure.

Intacs

Though less well known, these small implants can improve visionin patients with mild to moderate without the risk ofpermanent eye damage inherent in the tissue removal technique ofLASIK. Intacs are semi-circular disks implanted in the corneawhich stretch it to assume a flatter shape. Though slightly lessprecise than LASIK, they are removeable and replaceable, so ifthe patient has an unexpected over- or under-correction, theimplant can be removed and another of a different size insertedto obtain the desired correction. The implants are located atthe edge of the cornea, so the central visual area is completelyintact and undamaged, and the strength of the cornea isundiminished, making it a better option for pilots and those whoengage in contact sports where eye injury is a possibility.

Intacs are unsuitable for severe and more than minorastigmatism (1.00 diopters), as the cornea can only be stretchedso far. If the Intacs are removed, vision returns to itspreoperative level. Aside from vision correction, Intacs arealso used to treat keratoconus.

Intacs are FDA approved and 10 year studies have revealed nomajor 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, theIntacs website gives a list of practitioners in each state, aswell a few in Canada, Europe and Mexico.

Implants

Because many people do not want to risk LASIK and Intacs cannothelp those with severe vision problems, intraocular lensimplants (IOL) are a new option approved by the FDA in 2004 tocorrect moderate to severe nearsightedness. The Artisan lens,manufactured by Ophtec, is similar to the type of lens implantutilized to restore vision following cataract eye surgery.

The new IOL, called the Artisan, is intended for only patientswho have 2.5 diopters or less of astigmatism.

The artificial lens does not replace the natural lens, but isinserted in front of it. The main problem found with the implantwas the steady loss of endothelial cells in the corneas ofpatients who received the implants. The endothelium is a layerof cells that line the undersurface of the cornea and areessential in keeping the cornea clear. A three-year study showeda continual steady loss of endothelial cells of 1.8 percent ayear. At this point, no one can predict whether this loss willproceed at the same rate indefinitely, or even its impact oncorneal function.

To minimize long-term effects of the device on the cornealendothelium, the FDA is requiring that the new lenses belabelled to specify that they should only be implanted inpatients whose corneal endothelial cells are thick enough towithstand minor cell loss.

More serious complications were few: retinal detachment (0.6%),cataract development (0.6%), and corneal swelling (0.4%). TheFDA is requiring Ophtec to conduct a five-year follow-up surveyof its implant patients to better assess the post-surgicalincidence of cataract development, retinal detachment and otherophthalmic diseases.

The Artisan lens is intended to be a permanent implant.Though itcan be removed surgically, vision may not always return to whatit was prior to getting the lens. Because it does not affectastigmatism, patients with this problem might still requireglasses.