The implantation of artificial intraocular lenses (IOLs) in the eye has been a part of cataract surgery for many years. However, it is only relatively recently that trials have begun in the United States for approval of IOLs for correction of high myopia and hyperopia that are with out existing cataracts. Several of these trials are nearing completion, with some of them closed to further participants, and FDA approval of one or more of these types of lenses is anticipated in the next six months to two years. Until then, this surgery is available in the United States with participation in the trials that are still open or through travel overseas.
In the phakic IOL procedure, a thin plastic lens is implanted inside the eye — either in front of the iris or behind the pupil (between the pupil and the eye's natural crystalline lens. Phakic IOLs are currently approved for use in the U.S. and visual outcomes are excellent. Most refractive surgeons today believe phakic IOLs are the procedure of choice for high myopia and high hyperopia, rather than LASIK.
Advantages of phakic IOLs include no thinning of the cornea and the ability to remove the implanted lens if problems arise or a change in the power of the lens is required. And because the eye's natural lens is left intact, there is no loss in the patients ability to change focus (if they are under age 40 and do not have presbyopia).
The implantation procedure is the same as for cataract surgery. Anesthetic drops are placed in the eye. Then a small incision of about 3 millimeters is made where the cornea and the white of the eye (sclera) meet. Unlike cataract surgery, portions of the lens are not removed at this time. Instead, the artificial intraocular lens is folded and placed within the posterior chamber of the eye, behind the iris and the natural lens. This placement has been associated with an increase in developments of cataracts, although changes in the surgical procedure is thought to now increase aqueous flow between the implanted lens and the natural lens, which is expected to reduce cataract formation.
After surgery, a temporary protective shield will be placed over your eye to protect it for the first few hours after the procedure.
The results of the surgery are almost immediate, but your vision will probably be a little blurry from the anesthesia.
You'll need someone to drive you home after the procedure.
You should relax for the rest of the day after surgery.
You may experience some discomfort after the anesthesia wears off, but this is usually relieved effectively with an over-the-counter pain reliever.
Most patients resume normal activities within a day or two.
By implanting a lens in the eye, the need for glasses or contact lenses is eliminated. Implanted lenses provide a highly predictable alteration in vision, unlike other refractive surgeries that rely on the healing process to result in the final refractive state. Phakic IOLs almost always meet or exceed the best vision achievable using eyeglasses or contacts, a final result not always achieved with LASIK or other surgeries. Because of the stability of the artificial lens, the results do not regress over time, as is sometimes seen with LASIK and LTK. For several types of lenses, the surgical process is closely related to cataract surgery, so with only minor adjustments many, many surgeons are experienced in the implant procedure. Additionally, this surgery keeps the cornea and lens in its natural state, allowing the process to be reversed if necessary.
One of the most significant benefits of this surgery is the ability to treat with equal efficiency mild to severe nearsightedness and farsightedness, even to a refractive error that requires correction in the 10 to 20 diopter range. This is beyond what is recommended for treatment using LASIK or other laser based surgeries.
In addition to being able to correct higher prescription powers than LASIK, another advantage of the phakic IOL procedure is that it's completely reversible.
According to Advanced Medical Optics (AMO), "With over 18 years of use and 150,000 procedures performed worldwide, results prove that the Verisyse design is safe and effective for very nearsighted people who are tired of thick glasses and are not candidates for Custom LASIK." [1]
Though the risks of phakic IOL surgery are low, potential complications include:
Inflammation
Infection
Cataracts
Retinal detachment
Corneal damage
If you are considering phakic IOL surgery, be sure to discuss the risks and potential complications of this procedure with your surgeon as part of your pre-operative consultation.
