In addition to glasses and contacts for vision correction, there are surgical alternatives to LASIK such as PRK, IOLs, or ICLs.
PRK employs the WaveLight® EX500 Laser but the surgical access to your cornea varies from LASIK.
Lens Replacement with IOLs, the same surgery used for patients who have poor vision due to cataracts, can also be used for patients who desire vision correction.
ICL vision correction is an emerging technology that Dr. Winthrop does not yet endorse.
PRK (Photorefractive keratectomy) is the original laser eye surgery, invented in the early 1980s. The first FDA approval of a laser for PRK in the U.S. was in 1995, but the procedure was practiced abroad for years before that. In fact, many Americans had the surgery done in Canada and Mexico before it was available here.
Both PRK eye surgery and LASIK eye surgery are used to treat myopia, hyperopia, and astigmatism, and both procedures work by using the same excimer laser to reshape the cornea to correct vision. PRK is different from LASIK in that a flap is not created. Both PRK and LASIK are grouped under the umbrella “laser eye surgery,” but each is a little different when it comes to advantages and disadvantages.
During LASIK eye surgery, I use a microkeratome to create a corneal flap. This flap of tissue is folded back, exposing the inner stromal corneal bed where the treatment will take place. The flap is then repositioned. For PRK an instrument is used to wipe off the top epithelium (the outer layer of the cornea). The anterior (or top) corneal stroma is then ablated with the laser.
The removal of the epithelium creates a situation equivalent to a scratched eye or corneal abrasion that causes irritation, watering of the eye, and blurry vision. To minimize these symptoms a special bandage soft contact lens is placed to promote healing of the epithelium. This lens is typically left in place for 3 days until the epithelium has healed underneath.
PRK and LASIK produce similar vision correction results. LASIK patients have less discomfort and obtain good vision more quickly whereas improvement with PRK is gradual and takes days, weeks or even months before final, optimal visual acuity sets in. The main advantage of PRK is that patients who are not candidates for LASIK due to certain conditions such as thin corneas or corneal scars can often be effectively treated with PRK eye surgery.
PRK is an ambulatory procedure done in my office. You walk into the laser suite, have PRK and walk out again. In fact, the actual surgery only takes a few minutes and although you are awake the whole time I will give you a mild oral sedative beforehand.
Many patients are concerned that PRK will hurt. To ensure maximum comfort, numbing eye drops are used and the vast majority of patients report that the procedure itself is pain-free. The first few days following your PRK procedure, however, your eyes may hurt slightly as the epithelium heals and covers the treated area. Eye drops, pain medication, and protective bandage soft contact lenses will be used to minimize this discomfort, and most patients find that they are able to resume normal activities within three to seven days.
Vision correction with Intraocular Lenses (IOLs) is variously called Clear Lens Extraction (CLE) or Refractive Lensectomy (RLE). This method of lens exchange has been used successfully for over three decades of lens implantation for cataract patients, where nature's own lens has been clouded over from the effects of oxidation and aging. As long as surgeons were putting in a new lens, it was always the goal to put in that power which was correctly matched to give the patient their desired plane of vision, far or near.
Today the ability to achieve vision correction with intraocular lenses is no longer reserved for those with aging or cataractous eyes. The same decreased dependence on glasses or contact lenses can now be achieved in otherwise healthy and relatively younger eyes through the use of modern intraocular lenses (IOLs). In CLE or RLE procedures it is possible to set one's focus at distance with a monofocal (single focus) IOL. This can even be accomplished in patients with astigmatism through Toric IOLs. Single focus IOLs can even be used to duplicate the situation called monovision that so many contact lens individuals employ to see far and near, eliminating contacts altogether.
Newer advances in intraocular lenses have even led to accommodating and multifocal lenses. The Crystalens accommodating lenses actually change shape within the eye (much as the natural lens does before presbyopia arrives in our 40s) to provide vision at a distance (driving, television, spectator activities), intermediate (computers, cards, hobbies), and near (print, cell phones, etc). The ReStor lens from Alcon Laboratories and the Technis Multifocal both provide good distance and near vision at the same time.
Among the newest advances in vision-correcting procedures is the insertable contact lens, but Dr. Winthrop feels that the complication rate with the procedure remains too high so he does not recommend ICLs to his patients at this time.
It is a clever concept that is similar in one manner to the intraocular lens (IOL) in that an artificial plastic lens is inserted in the eye. But this time, rather than being placed in the vacant area that is created by removal of the natural lens, the ICL is placed between the iris (colored part of the eye) and the cornea (the clear window that sits forward of the iris). This placement is highly sensitive, as the angle between the iris and the cornea can be very narrow. The natural channel that helps to maintain the eye’s normal pressure can get closed off in some cases with the ICLs, resulting in high eye pressure. Other complications can include chafing of the iris or the natural lens, resulting in iritis and cataract formation, respectively; in addition, the innermost layer of the cornea (the endothelium) can be compromised resulting in poor vision. This layer does not renew itself and so must be respected. In time, these potential problems may be resolved by a change in the procedure and/or technology.
– Patti Corbett