Intraocular Lenses (IOLs)

Medically reviewed by Joseph Christenbury, M.D.

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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. Other monofocal IOLs can correct corneal astigmatism in addition to providing vision at a distinct focal point.

Are You a Candidate?

Most people who are a candidate for an IOL have a visually significant cataract and are healthy enough for cataract surgery. These patients wish to reduce their dependency on glasses and contact lenses. IOLs are not typically used as a treatment for nearsightedness (myopia) or farsightedness (hyperopia) in younger individuals as there are less invasive treatments available for these common vision problems such as LASIK.

Monofocal IOLs

A monofocal IOL is the most common type of intraocular lens that a surgeon places into the eye after cataract surgery. It is designed to have a single focal point, and this focal point can be customized to give the patient distance, intermediate or near vision. Typically most patients choose to have distance vision in both eyes when these lenses are implanted, and as a result the near vision is not as sharp. This can be easily treated by the patient using reading glasses.

Patients can also choose to have one eye set for distance and one for intermediate or near vision, a phenomenon called monovision. This can reduce the need for reading glasses after cataract surgery. Monovision can work well for many patients. However, some patients who choose monovision may have issues afterwards with balance and depth perception, so this should be discussed with your surgeon in the preoperative visit prior to cataract surgery. Your doctor may choose for you to do a contact lens trial of monovision prior to the surgery to see if it is acceptable.

IOL surgery with a monofocal lens is an outpatient procedure that typically takes 30 minutes or less to perform. The patient is awake during the procedure, though the eyes are anesthetized with eye drops or local anesthesia 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.

Monofocal 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 notice vision disturbances such as glare and halos around lights. These effects are common to most lens based 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 monofocal lens. Patients typically adapt to their new 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 touch the surface of the eyes.

Most insurance plans will pay the basic costs of surgery for a monofocal lens, however depending on the patient’s insurance a copay for the surgery or the hospital or anesthesia fees may be required.

Toric IOLs

A toric IOL is a special type of monofocal IOL. In addition to correcting vision at a specified distance, it simultaneously can correct astigmatism in the cornea. It has marking points on the lens that the surgeon will use to align the toric IOL to the axis at which it will correct the maximum amount of astigmatism. To determine which toric IOL will be used, your eye surgeon will take additional preoperative measurements (in addition to a complete eye exam) including a map of the cornea and measurement of the dimensions of your eye. These tests allow the surgeon to determine where to precisely place the lens inside your eye.

Toric IOL surgery is an outpatient procedure similar to implant a monofocal IOL and typically takes 30 minutes or less to perform. 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.

Toric 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 notice vision disturbances such as glare, halos around lights and poor night vision. These effects usually become less distracting over time as the eyes heal.

It may take the brain some time to adjust to focusing with the toric lens. Patients typically adapt to their new 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 touch the surface of the eyes.

Toric lenses are considered to be ‘premium’ IOLs, and therefore tend to be more expensive. Depending on the specific brand of IOL, they can cost as much as $1,000 to $1,500 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 cataract surgery, extra costs may be required for toric IOLs.

Multifocal IOLs

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 most multifocal IOL patients 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 typically takes 30 minutes or less to perform. The patient is awake during the procedure, though the eyes are anesthetized with eye drops or local anesthesia 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 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 adapt to their new vision over a period of several weeks or months as this adjustment occurs. In general, patients are advised to take a week away from work and avoid anything that may irritate, strain or touch the surface of 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 or more 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

Accommodating IOLs, are a distinct type of intraocular lens implant that also reduces the dependence on reading glasses. Like multifocal IOLs, accommodating IOLs are intended to provide sharper vision at multiple distances. Impaired accommodation is often related to the inflexibility of the aging natural lens, preventing it from sharp changes in focus. 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. Accomodating IOLs can be used as a treatment for presbyopia, and accommodating IOLs can be implanted at the time of cataract surgery.

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 accommodating IOLs, Bausch + Lomb’s Crystalens is one of the most frequently used FDA-approved accommodating IOLs.

Accommodating IOL implantation is an outpatient procedure that takes 30 minutes or less 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 or cataract 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 sutures. Patients are free to return home after the procedure, though their eyesight will be blurry.
The risks associated with accommodating IOLs are small, though there is a chance that infection and shifting of the artificial lens may occur. The shifting side effect is something the patient should discuss the possibility of happening when you speak with your surgeon in the preoperative visit. In addition, the artificial lens can develop a film that clouds vision. Known as posterior capsule opacification, this side effect can be treated to improve the 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.

The full cost of an accommodating IOL such as the Crystalens is not typically covered by health insurance. Using an accommodating lens may add at least $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.