Refractive Lens Exchange — Once in a Lifetime
Those seeking freedom from contact lenses and glasses have realized by now that presbyopia creates a problem. Presbyopia, literally “old eyes,” is the aging process that causes loss of elasticity in the lens of the eye so that we all need reading glasses, progressive lenses, bifocals, trifocals, contact lens monovision or multifocal contact lenses after the age of about 45. Whatever vision correction was needed before the onset of presbyopia, some additional correction is required afterwards so that we can read, use the computer and see small objects up close.
Corneal refractive procedures such as LASIK and PRK provide satisfaction 95% of the time (according to testimony at the recent FDA hearing) and really do a great job correcting nearsightedness, farsightedness and astigmatism (within limits). Phakic refractive lenses (such as the ICL and Verisyse) can correct even higher degrees of nearsightedness and astigmatism. However, those who have enjoyed total freedom from glasses and contacts by virtue of one of these procedures will find they are again putting on glasses before they hit their 50th birthdays — this time, however, the glasses will be over-the-counter reading glasses. Not too much trouble for some, others may find the gap in clarity between distance and near problematic. These people then turn to trifocals or progressive lenses to obtain a complete range of vision. Soon they have quite a few pairs, in the car, in the office, at home, everywhere. Frustration, thy name is Presbyopia!
Growing out of procedures and technology developed for cataract surgery, Refractive Lens Exchange is filling the need for independence from glasses for those over 45. In the United States we now have three approved implants (intraocular lenses, or IOLs) that correct Presbyopia: ReZoom (AMO, Santa Ana, CA), ReStor (Alcon, Ft. Worth, TX) and crystalens (Bausch & Lomb, San Dimas, CA). The ReZoom and ReStor are multifocal IOLs, providing multiple focal points. Due to fortuitously complementary properties they can be mixed (ReStor in one eye, ReZoom in the other) to achieve a very high level of independence from glasses. Multifocal IOLs are not perfect — there is a decrease in contrast sensitivity relative to young, healthy, normal subjects, and there may be rings around point sources of light at night, like headlights. Nevertheless, multifocals offer the highest chance of not needing to wear glasses for both distance (driving) and near (reading) activities.
The crystalens is an accommodative lens, designed to shift focus from distance to near. Contrast is maintained with this implant (unlike multifocal IOLs), but the chance of needing additional correction for reading (reading glasses again) is higher than with multifocals. Pending approval by the FDA is a new version of the crystalens designed to improve near vision without sacrificing contrast sensitivity. Meanwhile, a second generation accommodative lens, the Synchrony (Visiogen, Aliso Viejo, CA) is currently in clinical investigation, and a new multifocal (Tecnis, AMO) is also awaiting a decision from the FDA.
For those who have never had eye surgery before, and for those who have, Refractive Lens Exchange offers a lifetime solution for visual freedom. Once the lens is replaced by a multifocal or accommodative IOL (and the results fine-tuned, if necessary) no further refractive procedure will ever be necessary. The refractive changes that occur in the eye after the age of 45 depend pretty much entirely on changes in the lens. Once the lens is replaced, the changes stop. Refractive Lens Exchange truly represents a once-in-a-lifetime solution.