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Multifocal intraocular lenses (IOLs) are used to replace cloudy lenses in people with cataracts. They might also be considered for people with presbyopia.
A multifocal intraocular lens can dramatically improve certain vision issues. Your doctor will assess whether having these lenses implanted is the best choice for your vision.
There are pros and cons to these lenses. They might not be the right choice for everyone with cataracts or presbyopia, and like any surgery, the procedure comes with risks. Generally, the benefits outweigh the risks.
It is a fairly straightforward surgery, however, so the recovery time might fit well with your lifestyle. There are possible complications to be aware of, so you can make an informed decision about this procedure.
What Is a Multifocal Intraocular Lens?
These lenses make it possible to see far and near more clearly. The lenses use different optical powers at different areas across the lens. They rely on the eye muscles to move when necessary to focus. It is best if someone gets the implants in both eyes rather than just one.
These lenses often allow people to stop wearing eyeglasses and contact lenses. On the surface of the lens, there is usually a form of concentric rings etched into it. This allows images at a variety of distances to focus on the retina.
It can take a little time for people to adapt to these lenses. This is because the focusing power the lenses provide is different than what people are used to. The brain needs time to adjust to the new way of focusing.
Types of Multifocal Lenses
Multifocal IOLs will either diffract, refract or refract and diffract the light from a near or far object while dispersing some of the light. As such, the IOLs are grouped into refractive, diffractive, or combined lenses.
- Refractive multifocal IOL models often support the intermediate and far vision. They depend on pupil dynamics, are quite sensitive to centering, and sometimes have a continuous curvature change to support optimal vision across all distances.
- Diffractive multifocal IOL models have concentric rings located further apart as they move from the center. Though they generally have a good near and far vision, their intermediate vision is not always satisfactory.
How Do Cataracts Affect Vision?
A survey in 2015 estimated that in the U.S., over 24.4 million people ages 40 and older are affected by cataracts. A cataract is a condition where the lens of the eye becomes cloudy. This makes it difficult to read, see people, and drive, especially at night.
In most cases, a cataract forms when the eye lens tissue changes due to injury or aging. These factors can cause the lens to become less flexible, thicker, and less transparent.
Most cases of cataracts happen in both eyes. However, their progression is not even between both eyes. It is common for one cataract to be far more advanced than the other.
Cataracts can affect vision in the following ways:
- Trying to see clearly at night becomes increasingly difficult.
- When reading or performing similar activities, someone has to keep making the space brighter to see.
- A person’s contact lens or eyeglass prescription changes frequently.
- One eye develops double vision.
- Vision becomes blurry, cloudy, or dim.
- People experience glare and become sensitive to light.
- Colors appear yellow or faded.
As cataracts grow, vision symptoms tend to become worse. When looking at the affected eye, it is visibly different, and the clouding is apparent.
Presbyopia and Vision
People can start to notice symptoms as early as their 40s. It continues to progress as people get older.
The symptoms associated with presbyopia include:
- At a normal reading distance, vision is blurry.
- To make the material clearer, the person holds reading material at a further distance.
- Headaches and eyestrain, especially when doing up-close work or reading.
The lens of the eye becomes harder as people get older, and this is what causes presbyopia. The lens needs to change shape to allow the eyes to focus on close images.
As it hardens, it loses its flexibility to make the necessary shape changes. Ultimately, this makes things look like they are out of focus, giving them a blurry appearance.
Primary Brands of Multifocal Intraocular Lenses
There are three common multifocal lenses for people to choose from. These include:
- TECNIS Multifocal: This is a fully diffractive IOL with advanced image quality across all distances under all lighting conditions and for all pupil sizes.
- AcrySof IQ ReSTOR: This brand has a patented apodized diffractive feature to distribute light based on the ambient lighting in a room. It optimizes your image quality in diverse lighting.
- ReZoom: The multifocal lenses from this brand have five optical zones etched microscopically into its surface. It improves near, distant, and intermediate vision.
The best lens depends on several factors, such as the person’s overall eye health, their occupation, and their lifestyle. The eye doctor will perform an extensive interview and assessment, so they can recommend the best choice.
The following are success statistics regarding different multifocal intraocular lens brands:
- The clinical trials performed by the FDA showed that 92 percent of people who received ReZoom lenses either never needed glasses again or only needed them occasionally.
- TECNIS multifocal IOL clinical studies determined that about 88 percent of the people studied did not have to wear glasses after having the surgery.
- ReSTOR multifocal IOL clinical results concluded that 80 percent of the participants in the trials did not have to wear their eyeglasses after the implant was in place.
- Crystalens accommodating IOL FDA trials determined that over 88 percent of the people in the study achieved 20/40 uncorrected visual acuity or better. This was at all distances.
Pros and Cons
Multifocal IOLs all work to improve intermediate, far, and near distances. In many cases, after having the lenses implanted, people no longer need to wear corrective lenses to see clearly. The results are usually long-lasting, and there is no upkeep since the lenses are implanted in the eye.
There are a few disadvantages to consider as well. Seeing at close distances is sometimes an issue for people with multifocal IOLs. However, reading glasses usually correct this problem.
People who get these lenses as part of cataract surgery may find it hard to read in dim light. While rare, some people develop halos and glares surrounding lights after dark, which can interfere with safe driving at night.
Lens Replacement Surgery
Implanting multifocal IOLs is nearly the same as cataract surgery. It involves removing the natural lens so the doctor can put the multifocal lens into place.
Before having the surgery, there are some preparation steps a doctor might ask people to take:
- Go through testing to measure the shape and size of the eye using ultrasound.
- Reduce the risk of infection by using antibiotic eyedrops.
- Temporarily stop certain medications that may interfere with the procedure.
- Fast for about 12 hours before the procedure begins.
The actual procedure involves removing the lens and putting the new one into place. A small incision is made into the cornea to remove and place the lenses.
Once the surgery is over, no stitches are put into the incisions since they will close by themselves. The doctor puts a shield over the eye, and people remain in a recovery room for up to 30 minutes. After this, people can go home to continue with recovery.
Following the procedure, people may need to shield their eyes and avoid getting water in the eye. Doctors may prescribe eyedrops. The eyedrops are typically antibiotics to reduce the risk of infection.
Possible Complications After Surgery
Since this procedure is almost identical to cataract surgery, most of the possible complications are the same.
- Posterior capsule opacity, in which the back of the lens capsule becomes hazy
- Eye inflammation
- Perceived flashes of light
- Droopy eyelid
- Intraocular lens dislocation
- Light sensitivity
- Macular edema (swelling of the central retina)
- Elevated eye pressure
Multifocal intraocular lenses are a good choice for many people. However, it is important to explore all of the details before agreeing to the procedure.
An eye doctor can answer all your questions. Once you agree to the surgery, you can be sure that you have made an informed choice.
Cost of IOLs
Cataract procedures for someone without insurance cost between $3,000 and $5,000 per eye for a standard surgery and $4,000 to $6,000 per eye for a laser-assisted procedure with advanced lens implants.
If you have insurance, those costs will be less, and they will depend on your plan, your specific deductible and your out-of-pocket maximums.
Medicare does cover cataract surgery, but coverage varies based on which lens you need or choose to have. With Medicare Part B, patients pay 20% of the Medicare-approved amount for lenses.
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Cost-Effective Analysis of Multifocal Intraocular Lenses Compared to Monofocal Intraocular Lenses in Cataract Surgery. (December 2019). American Journal of Ophthalmology.
How Much Does Cataract Surgery Cost? (July 2021). UCF Health.
Candidacy for multifocal IOLs. (July 2021). Cataract & Refractive Surgery Today.