Preparing for cataract surgery? Before your operation, your surgeon will review the intraocular lens (IOL) replacement options. They fall into two basic categories-monofocal (fixed focus) and multifocal or accommodative lenses. A number of factors can affect your lens choices. Here are a few things to consider before you head to surgery.
Pros and cons of monofocal lenses
With monofocal lenses, your vision is typically in focus at only one distance-near, intermediate, or far. Alternatively, you can choose to have an IOL implanted in one eye to improve your distance vision and one implanted in the other eye to improve your near vision. This technique is referred to as monovision.
- The cost of standard monofocal lenses is fully covered by Medicare and private insurance.
- People with monofocal IOLs typically wear glasses for driving, especially at night or in unfamiliar territory. Near vision is preserved in low light, whereas it may be reduced with multifocal IOLs.
- A toric lens, which corrects for astigmatism, is available. Considered a “premium” monofocal lens, the additional cost of this type of lens is not covered by medical insurance.
- If you have trouble with both your distance vision and your near vision, you’ll still need glasses. If you choose the IOL for distance vision correction, you will need reading glasses to improve your near vision. Conversely, if you choose an IOL for near vision correction, you will need glasses to improve your distance vision.
- Not everyone adjusts well to monovision as the brain tries to process the differing information it’s receiving from both eyes.
- Vision may still be blurry at both distance and near when you are not wearing glasses if you have significant astigmatism and choose a standard monofocal lens.
Multifocal and accommodative lenses
Multifocal IOLs and accommodative lenses are designed to allow you to see more clearly at near, intermediate, and far distances. Multifocal IOLs are made up of concentric rings of varying optical power, each of which refracts, or bends, incoming light, bringing it into focus at different points simultaneously. Accommodative lenses rely on certain muscles in the eye to move the IOL forward and backward, thereby changing the focus. Both of these lenses provide the best results when used in both eyes.
- Approximately 85 percent of people who receive multifocal IOLs find that they do not need glasses for distance or near activities.
- Accommodative lenses typically confer very good distance and intermediate (for example, computer) vision, but reading vision is not as good. A toric-accommodating IOL, which corrects for astigmatism, is now available.
- About 5 to 10 percent of people receiving multifocal implants complain of some glare or halos around lights at night. These symptoms are less common with accommodative implants.
- Multifocal lenses (but not accommodative lenses) are associated with some loss of contrast, typically experienced as a loss of some clarity in low light situations, such as reading a menu in a dark restaurant.
- Medicare and private insurers will not pay the costs of the lens and associated services that exceed the charges for a conventional IOL.
The bottom line
Consider conventional monofocal IOLs if you:
- Won’t mind wearing glasses after surgery.
- Don’t feel that multifocal or accommodative lenses are worth the extra cost.
- Are a candidate for multifocal/accommodative lenses but can’t live with less-than-perfect vision in all situations.
Consider multifocal IOLs if you:
- Place a high value on reducing dependency on eyeglasses, especially for reading.
- Understand their advantages and limitations-none give you the range and clarity that you likely had in your 20s, if you did not need glasses then.
- Don’t mind the extra out-of-pocket costs you’ll need to pay for premium lenses.
Lenses in the pipeline
Cataract surgery patients are likely to have more types of intraocular lenses (IOLs) to choose from in the future, judging from the number of IOLs that are now in development. Among them are:
- A light-adjustable lens (LAL), which allows surgeons to use a specialized laser to alter the shape of the lens for better vision correction, even after the lens has been surgically implanted. The LAL, already available in some countries outside the United States, is in the final phase of clinical trials.
- A fluid-based accommodating IOL, which changes shape and thickness with the natural muscle movement of the eye, depending on the need for distance or near vision. Clinical studies are just beginning.