Surgery for cataracts involves removing the natural lens of the eye that contains the cataract and either replacing it with an artificial lens called an intraocular lens implant (IOL) or compensating for its absence with eyeglasses or contact lenses. See a picture of the lens.

The most common replacement is an IOL. Before having surgery, review with your doctor the advantages and disadvantages of each type of replacement lens. A variety of IOL types are available, and your doctor can help you choose the type that may work best for you.

An IOL is placed inside the eye during surgery. Corrective glasses may be needed after surgery for reading and close work, but they are not as thick and heavy as traditional cataract glasses.

IOLs are commonly chosen to provide better distance vision than near vision, and glasses are used for sharp near vision. However, some people choose IOLs that provide better near vision for reading and use glasses for distance vision.

If you are having the lenses in both eyes replaced, your doctor may recommend monovision. With monovision, the IOL in one eye provides for better near vision, and an IOL that gives better distance vision is implanted in the other eye. Most people who try monovision can adjust to it. Monovision has some drawbacks, however. Each eye must work more independently, which can cause problems with depth perception. You may have to adjust your gaze more often to allow one eye or the other to see properly.

When thinking about how an IOL will affect your vision following cataract surgery, the two main types of IOL to consider are:

• Monofocal IOLs. This type of intraocular lens is shaped to provide good vision in just one particular range of distances, either near or distance vision. If you have this type of IOL implanted in your eye(s), you will probably need glasses to provide clear vision in the other range. For example, it is common for the IOLs to be chosen to provide better distance vision than near vision, and glasses are used for sharp near vision. This is the most common choice.
• Multifocal IOLs. This type of intraocular lens design provides correction for both near and distance vision, and both near and far objects can be in focus at the same time. Your brain must learn to select the visual information it needs to form an image of either near or distant objects, so multifocal IOLs may require some adjustment. A person may adjust better to multifocal IOLs if they are placed in both eyes. Not everyone is a candidate for this type of lens.

If you are considering cataract surgery to replace the lens in your eye(s), you should discuss with your doctor which of the different types of IOL is most likely to work best for you.

IOLs may not be used in infants younger than age 2.

IOLs are now being used more commonly in children. However, some controversy still exists over their suitability for very young children, since it is not clear how well the material IOLs are made of will last over a lifetime.¹

Studies are being done to determine the age at which children can begin to benefit from an IOL. If your child needs cataract surgery, talk with your eye specialist (preferably a pediatric ophthalmologist) about what current studies are showing about the use of IOLs in children.