Intraocular lenses, commonly referred to as IOLs, are artificial lenses that can be implanted into the eye in order to correct vision problems caused by the natural lens. FDA-approved since 1981, IOLs are often used to treat clouding of the lens caused by cataracts, though they also serve as a treatment option for a variety of other eye problems, including astigmatism and presbyopia.
Most IOLs are round devices made of plastic, acrylic or silicone that measure about a quarter of an inch in diameter. Some may have two “arms” designed to keep the device in place once implanted. IOL technology is constantly evolving with the development of newer varieties. For example, some of the newer IOLs have a soft design that makes them foldable during implantation, allowing for a significantly smaller corneal incision. Some are considered to be monofocal (offering vision at one distance — far, intermediate or near – only) while others are multifocal or accommodating, meaning that they are able to provide clear vision at a range of distances.
Are You a Candidate?
Good candidates for IOLs are adults who are otherwise healthy, who wish to reduce their dependency on glasses and contact lenses. IOLs can be used to treat more severe vision problems otherwise not treatable by LASIK and other laser eye surgeries. However, they are not typically used as a treatment for nearsightedness (myopia) or farsightedness (hyperopia) as there are less invasive treatments available for these common vision problems.
Multifocal IOLs differ from traditional monofocal IOLs in that they provide vision correction across multiple distances. A standard monofocal IOL may improve distance vision while leaving near vision impaired. In fact, it is not uncommon for someone who has undergone monofocal IOL implantation to require reading glasses.
Unlike the natural lens, the artificial multifocal lens does not function by relying on the eye muscle to change the shape of the lens. Instead, it has different areas for vision at different distances similar to bifocal eyeglasses. Unlike monofocal IOL patients, the majority of multifocal IOL recipients find themselves less dependent on contact lenses or glasses.
Common multifocal IOL brands include ReSTOR, ReZoom and Tecnis.
Multifocal IOL surgery is an outpatient procedure that is typically performed in an hour or less. The patient is awake during the procedure, though the eyes are anesthetized with eye drops to minimize discomfort. A small incision in the front of the eye enables the surgeon to remove the natural lens, replacing it with a multifocal lens. Once in the correct position, the incision may or may not be closed with sutures. Patients are free to return home following the procedure, though their vision will be blurry and they’ll need someone to drive them.
Multifocal IOL implantation is a safe and effective procedure; however, as with any surgery there are risks. Infection and incomplete vision correction may occur in rare instances. In addition, some patients with multifocal lenses notice vision disturbances such as glare, halos around lights and poor night vision. These effects are common to most refractive surgeries and usually become less distracting over time as the eyes heal.
It may take the brain some time to adjust to focusing with the multifocal lens. Patients typically notice that they become less aware of their vision over a period of several weeks as this adjustment occurs. In general, patients are advised to take a week away from work and avoid anything that may irritate, strain or cause increased blood flow to the eyes.
Multifocal lenses are considered to be ‘premium’ IOLs, and therefore tend to be more expensive. Depending on the specific brand of multifocal IOL, they can cost as much as $2,500 per eye on top of the standard cost of implanting an IOL, which is usually $1,500 to $4,000 per eye. While most insurance plans will pay the basic costs of surgery, extra costs may be required for multifocal IOLs.
Accommodating IOLs, also known as presbyopia-correcting or ‘premium’ IOLs, represent a new generation of intraocular lens implants. Like multifocal IOLs, accommodating IOLs are intended to provide sharper vision at multiple distances. Vision problems are often related to the inflexibility of the aging natural lens, preventing it from sharp changes in focus (presbyopia). Accommodating IOLs mimic the flexibility of the eye’s natural lens by using the eye muscles to shift the position of the lens.
In general, accommodating IOL candidates are adults in good overall health with no serious eye diseases. Most patients are over 40, though some older patients may not have the eye muscle strength required to use the IOL to its fullest potential. Generally speaking, the longer someone has used reading glasses, the weaker the muscles are likely to be. Commonly used as a treatment for presbyopia, accommodating IOLs are also used to treat both cataracts and hyperopia.
Unlike the bifocal-like design of multifocal IOLs, a lens that has different ‘zones’ for multiple distances, accommodating lenses have only one ‘zone,’ relying on the eye’s own focusing abilities to enable clear vision at multiple distances. Whereas there are a number of different brands of multifocal IOL, Bausch + Lomb’s Crystalens is currently the only FDA-approved accommodating IOL.
Accommodating IOL implantation is an outpatient procedure that takes about an hour to perform. Anesthetic eye drops are applied before the treatment begins to help minimize patient discomfort. The surgeon then creates a small incision in the front of the eye, through which the natural lens is removed and replaced with the accommodating IOL. Once the lens has been implanted in the eye, the incision may or may not need to be closed with dissolvable sutures. Patients are free to return home after the procedure, though their eyesight will be blurry.
The risks associated with accommodating IOLs are minimal, though there is a chance that infection and shifting of the artificial lens may occur. In addition, the artificial lens can develop a film that clouds vision. Known as posterior capsule opacification, this rare side effect can be treated, restoring vision.
Procedure recovery time is usually one to two weeks, with most patients returning to work and resuming driving within a week. Minor vision disturbances may be noticeable until the eyes are fully healed. During this time, it is important to avoid irritating or straining the eyes. For the first six months after surgery, regularly performing eye exercises such as word games and puzzles can strengthen the muscles of the eye, enabling patients to attain the maximum benefit from their accommodating lenses. In clinical studies, 80 percent of people with Crystalens achieved 20/20 or better near vision.
The full cost of premium IOLs such as Crystalens is not typically covered by health insurance. Using an accommodating lens may add as much as $2,500 out-of-pocket per eye, in addition to the standard costs of IOL implantation, which are usually between $1,500 and $4,000 per eye. If you are considering accommodating lenses, ask your eye doctor about payment plans and financing options that can make this decision more affordable.