Intraocular Lenses (IOLs)

Before intraocular lenses (IOLs) were developed, people had to wear very thick eyeglasses or special contact lenses to be able to see after cataract surgery. There are now several types of IOL implants available to help people enjoy improved vision with little or no dependence on glasses. Dr. Callahan will discuss these options with you to determine what best suits your vision and lifestyle needs.

The IOL is usually placed in the same position as the natural lens of the eye. It also has the same function: to focus the light that comes into your eye through the cornea and pupil onto the retina, which in turn relays images through the optic nerve to the brain. Most IOLs are made of silicone or acrylic and are foldable so they can be injected into the eye through the same small incision through which the cataract was removed. The central part of the IOL is about 6 mm or one-third the size of a dime. IOLs include filters to protect the eye’s retina from exposure to UV and other potentially damaging light radiation. Based on your preoperative measurements and goals, the IOL will contain the appropriate prescription to give you the best vision possible.

Video: IOL Options

This video demonstrates how different IOLs can provide patients with a wide range of visual clarity and focusing capability after cataract surgery. IOLs included in this video are: Monofocal, Monofocal Toric, Multifocal and Accommodating.

IOLs – What is Right for Me?

Prior to surgery you and Dr. Callahan will decide which IOL is best for you. This will depend in part on how you feel about wearing glasses for reading and/or near vision, as well as on your visual needs. It also depends on your overall eye health and your preoperative measurements.

Click here to view more information on choosing the right lens (PDF)

Monofocal IOLs

This is the most commonly implanted IOL and has been used since the early 1970s. Monofocal IOLs are set to provide best-corrected vision at near, intermediate OR far distances. Most people who want a monofocal IOL choose to have their IOLs set for distance vision and use reading glasses for near activities. Monofocal IOLs do not allow the eye to accommodate or focus at different distances.

This is similar to presbyopia, a condition that affects all of us at some point, generally in our 40s. This causes difficulty focusing up close (i.e., problems with reading and other near tasks). While the cause of presbyopia is not completely understood, it is partially related to a decrease in the flexibility of the eye’s lens. Since presbyopia makes it difficult to see near objects clearly, even people without cataracts need reading glasses or an equivalent form of vision correction.

Patients may also choose to have monofocal IOLs set for near vision and wear glasses to see clearly in the distance. Another alternative is called monovision. In monovision, the IOL in the patient’s dominant eye is set for distance and the IOL in the other eye is set for near. The brain adapts and synthesizes the information from both eyes to provide vision at intermediate distances. This approach reduces or even eliminates the need for glasses altogether.

Not all people are able to tolerate monovision. It is most commonly done in patients who have worn monovision contact lenses. Other individuals considering monovision may be able to try this technique with contact lenses first to see how well they can adapt to monovision. It is important to understand that monovision involves a little bit of compromise in both distance and near vision.

It is important to know that standard monofocal IOLs do not correct astigmatism. Please see the Toric IOL section below for more information.

Premium or Lifestyle IOLs

For patients who meet certain criteria and are interested reducing their need for glasses as much as possible, there are other IOLs to consider. While Medicare and private insurance companies may still cover the cost of your cataract surgery, they do not generally cover the extra cost associated with these Premium or Lifestyle IOLs. Dr. Callahan will be happy to discuss this with you at your appointment.

Toric IOLs

This is an IOL that is designed to correct astigmatism that comes from the cornea (corneal astigmatism). In corneal astigmatism, the cornea (the clear front window of the eye) is not perfectly round like a basketball but rather is curved like a football. This results in the eye having more than one power. A standard, non-toric, monofocal IOL does not correct astigmatism. People with significant degrees of astigmatism are usually most satisfied with toric IOLs. Like the standard monofocal IOL, you may choose to have your toric IOL set for distance, intermediate, or near. Monovision is also an option with toric IOLs. There are other ways to correct astigmatism, and Dr. Callahan will discuss your options with you.

Click here to view additional information on the AcrySof® IP Toric IOL (PDF)

Video: AcrySof® Toric IOL

Patients with cataracts and astigmatism may choose to have the AcrySof® Toric Intra-Ocular Lens (IOL) that will clear the distorted vision caused by cataracts, as well as the distortions caused by astigmatism.

Multifocal and Accommodative IOLs

The newer IOL types reduce or eliminate the need for glasses or contact lenses. In the multifocal type, a series of focal zones or rings of different powers is designed into the IOL. Depending on where incoming light focuses through the zones, the person may be able to see both near and distant objects clearly.

The design of the accommodative lens allows certain eye muscles to move the IOL forward and backward, changing the focus much as it would with a natural lens. This allows for near and distance vision. There is a lot of variability in the amount of focusing ability with accommodative IOLs. The ability to read and perform other tasks without glasses varies from person to person, but is generally best when multifocal or accommodative IOLs are placed in both eyes. It usually takes six to 12 weeks after surgery on the second eye for the brain to adapt and vision improvement to be complete with either of these IOL types.

Video: Generic Multifocal IOL

Patients with cataracts can now choose to have a Multifocal Intra-Ocular Lens (IOL) that will clear the distorted vision caused by cataracts and provide patients with a full range of vision without dependence on glasses or contacts after surgery.

Considerations With Multifocal or Accommodative IOLs

For many people, these IOL types reduce but do not eliminate the need for glasses or contact lenses. For example, a person can read without glasses, but the words appear less clear than with glasses. A patient’s success with these IOLs may depend on the size of his or her pupils and other eye health factors, including astigmatism.

Side effects such as glare or halos around lights, or decreased sharpness of vision (contrast sensitivity) may occur, especially at night or in dim light. Most people adapt and are not bothered by these effects, but those who frequently drive at night or need very sharp focus for close-up work may be more satisfied with monofocal IOLs.

Each patient has different vision needs and wants, and these lenses are not for everyone. It is important to discuss these options carefully with Dr. Callahan.