A cataract—a clouding of the lens of the eye—blocks the normal passage of light through the eye.
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.
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. 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.
Studies are being done to find the age at which children can
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.
For nearsightedness, with or without cataracts
If you have cataracts and you are nearsighted, you may be able to have cataract surgery and get an IOL to help treat both issues. The chance of having retinal detachment after the surgery is higher than if you were not nearsighted, though. Talk to your doctor about all the pros and cons of cataract surgery.
If you don't have cataracts but you are nearsighted, there are two ways that IOLs may be able to help treat the nearsightedness:
When the surgeon replaces the eye's natural lens with an IOL, it's called "clear lens extraction."
When the surgeon does not remove the eye's natural lens, the IOL implants are called "phakic intraocular
lenses" or "implantable contact lenses." These IOLs are placed in front of the natural lens, either in front of or behind the iris.
Cataracts that begin in the center of the lens (nuclear cataracts) are the most common cause of
nearsightedness getting worse in adults.
Types of IOLs
Most people choose distance-vision IOLs over near-vision IOLs, and they use glasses for sharp near vision. But some people choose
IOLs that provide better near vision for reading, and they use glasses for distance
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. Many people who try monovision can adjust
to it. But it's not an option for everyone. One drawback of monovision is that each eye must work more
independently. This can cause problems with depth perception. You may have to
adjust your gaze more often to allow one eye or the other to see
When thinking about how an IOL will affect your vision following
cataract surgery, some types of IOL to consider are:
Multifocal (or accommodative) 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. This type of lens is not an option for some people. It may be considered a premium lens, so it might cost more than a monofocal IOL.
Monofocal IOLs. This type of intraocular lens is
designed for either
near or distance vision. If you have this type of IOL implanted in your eye(s),
you will probably need to also wear glasses. For
example, it is common for the IOLs to be chosen to provide better distance
vision than near vision. Then glasses are used for sharp near vision.
Toric IOLs. This is a type of monofocal IOL that helps correct astigmatism. It may be considered a premium lens, so it might cost more than a monofocal IOL.
Talk to your eye doctor about the pros and cons of each type of IOL.
How this information was developed to help you make better health decisions.