Image courtesy of Caitlin Albritton.
See Eye Anatomy
Why are lenses implanted during cataract surgery?
Cataract is the name given to the natural lens inside your eye when it becomes cloudy. When cataract interferes with vision, surgery is performed to remove the cloudy lens. In order to replace the focusing power of your natural lens, a synthetic lens implant is placed inside the eye at the time of cataract surgery.
What lens implant power options are available?
The patient may choose to have the power of the lens implant adjusted to focus the eye at various distances. The power calculations are not perfect and often glasses still must be worn by many patients. Most people choose to have the lens implant focused mainly for distance. Rarely, near-sighted patients prefer to keep the primary focus at near. Standard lens implants are fixed-focus lenses. That is, they do not focus at distance and near. For example, an eye with a standard lens implant focused for distance must use reading glasses for near work.
How can we decrease our dependence on glasses after cataract surgery?
In order to decrease the need for glasses, there are options to consider, each with advantages and disadvantages. Options include bifocal contact lenses, mono-vision lens implant correction, and multifocal lens implants.
Bifocal Contact lenses: This option may be good for patients who already use bifocal contact lenses. The contacts lenses help focus at near and may refine distance vision as needed.
Mono-vision Lens Implants: In this option one eye is focused mainly at distance and one eye is focused mainly for near. Not everyone can adapt to this situation and there is slight loss of depth perception with mono-vision correction. This option is best for those who already have adapted to mono-vision contact lenses.
Multifocal Lens Implants: This is a new option offered by premium lens implants that cost more for the patient. Basically, these implants offer improved range of focus for both distance and near. Many brands are available. The choice of lens depends on how much help with distance and near vision is desired. However, the greater the range of focus a given lens offers, the greater the side effects of the multifocal lens. Side effects include decreased contrast sensitivity and glare/halos from light especially at night. Loss of contrast sensitivity makes it more difficult to see gray print on white paper. Glare and halos bother some patients more than others.
A combination of strategies may be used. For example, a low-range-of-focus multifocal lensimplant (Symfony) may be used with mild mono-visionfocusing to minimize the downsides compared with each method when used alone.
Examples of multifocal lens implants include Symfony, Restor 2.5, and Restor 3.0. There are many others. Below is a chart to demonstrate the trade-offs among these lenses.
| Lens Implant Styles: Benefits and Limitations | ||||||
| Style | Distance vision | Intermediate vision | Near vision | Need for reading glasses | Contrast sensitivity | Glare/Halos |
| Standard IOL (monofocal) | Excellent | Fair | Poor | Most of the time | Excellent | Rare |
| Symfony IOL | Very good | Good | Fair | Much of the time | Good | Mild |
| Restor 2.5 IOL | Fairly good | Good | Good | Some of the time | Poor | Moderate |
| Restor 3.0 IOL | Fairly good | Fair | Good | Rarely needed | Poor | > Moderate |
If you have strong preferences, be sure to communicate with your doctor to be given the best lens implant for your situation. Keep in mind that the eye changes over time and the need for glasses may change over months to years after cataract surgery.
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