Perhaps you’ve been referred to an eye surgeon because cataracts have made your vision blurry and need to be removed. If you have severe cataracts, the only treatment is to remove the eye’s natural lens and replace it with an artificial intraocular lens (IOL). There are four different kinds of IOLs. Your eye surgeon will discuss with you which intraocular lens is right for you.
What is an IOL?
An IOL is a tiny, lightweight, clear plastic or silicone disc about the size of a small button. It is placed in the eye during cataract surgery to replace the focusing power of your eye’s natural lens. These lenses can be made of hard or soft plastic or soft silicone. Soft, foldable lenses can be inserted through a small incision, which shortens recovery time after surgery.
An intraocular lens can be implanted in front of or behind the iris but behind the iris is the usual placement. They have become a safe and practical way to restore normal sight after cataract surgery.
Standard Lenses
Standard IOLs are foldable lenses that are implanted through small self-sealing incisions. A patient must choose whether they want to be dependent on glasses for either reading or distance because these lenses provide good vision for only one focal distance. Also night vision and vision in low-contrast lighting will be somewhat reduced and patients with significant astigmatism will generally still need glasses for most activities.
If you want improved vision but don’t want to pay for premium lenses, choose standard IOLs. Most provincial and territorial health plans cover the cost of standard lenses.
Wavefront Lenses
Like standard IOLs, Wavefront intraocular lenses are foldable, implanted through small self-sealing incisions and provide good vision for only one focal distance. The difference is that Wavefront lenses use advanced aspheric optics designed to correct spherical abnormalities and increase contrast sensitivity. This is especially helpful during low-light or foggy conditions.
If you have no significant astigmatism and want the best possible vision available, you may be a candidate for Wavefront IOLs. However, these lenses are not always covered by health plans.
Toric Lenses
Toric, or astigmatism lenses are foldable and implanted through small self-sealing incisions. They reduce or eliminate astigmatism, which is an asymmetric curvature of the cornea that increases the need for glasses at all distances. Many patients receiving Toric lens implants no longer need glasses for distance vision but may still need reading glasses.
These lenses use standard spherical optics technology so, when the pupil is large, as during night-driving, dim lighting or in fog, some visual distortion and reduced contrast sensitivity will be evident.
Toric lenses are not usually covered by provincial and territorial health plans.
Multifocal/Accommodating Lenses
These lenses are also foldable and implanted the same way as described above. Multifocal/accommodating lenses offer the opportunity to see well at more than one distance, thus reducing the need for glasses or contacts. They work by assigning some of the light that enters the eye to near vision and some to distance vision. Accommodating lenses change position in the eye to match the task at hand.
Multifocal lenses are not the best choice for everyone as they can decrease contrast sensitivity and create visual irregularities such as glare and haloes around lights. Also, they are not appropriate for patients who have had previous eye trauma or who have unstable support structures for IOLs. Additional surgery would be needed for patients with significant astigmatism.
These lenses are not usually covered by health care plans.
