Multifocal IOLs Correction for Cataracts and Reading Vision
Multifocal IOLs are intraocular lenses that are implanted in the eye during refractive cataract surgery and refractive lens exchange (RLE). These premium IOLs are designed to restore vision at all distances and decrease your need for bifocals or reading glasses after surgery. Some studies suggest the surgical outcome may be improved for these lenses when a laser is used during cataract surgery.
As their name suggests, multifocal IOLs have more than one lens power. They work on the same principal as progressive eyeglass lenses and multifocal contact lenses — different zones in the lenses have different lens powers to improve vision at all distances. Surgery to implant these IOLs is the most popular type of surgery for correcting presbyopia, although some laser presbyopia surgery procedures are gaining wider use.
Why Multifocal IOLs?
Most IOLs used in cataract surgery are spherical, monofocal lenses that only correct nearsightedness or farsightedness. Unless a monovision correction is attempted where one eye is corrected for distance vision and the other is corrected for near vision reading glasses usually are required after surgery.
The need for reading glasses after cataract surgery is due in part because most people who need cataract surgery are over age 40 and have lost the ability to focus up close because of presbyopia LASIK. But even when cataracts occur in a young person, the lens changes that cause cataracts also affect the focusing flexibility of the eye.
Anyone who chooses to have a refractive lens exchange to reduce or eliminate large amounts of nearsightedness or farsightedness also will lose their ability to see clearly up close after surgery if a conventional monofocal IOL is used.
Any time the natural lens inside the eye (whether or not it is clouded by a cataract) is removed and replaced with a conventional IOL, the eye's ability to shift focus is eliminated. If the eye is corrected for distance vision with a conventional monofocal IOL, reading glasses usually are needed.
Multifocal IOLs address this limitation of conventional monofocal lens implants. Multifocal lenses have several lens powers to restore vision at multiple distances and reduce or eliminate the need for corrective eyewear after surgery.
The Multifocal IOL Procedure
The surgical procedure for implanting a multifocal IOL is the same as a normal cataract procedure.
Generally, the steps involved in a modern phacoemulsification-style cataract surgery (the most widely used cataract surgery performed in the United States) are:
- Anesthetic gel or eye drops are applied to your eye to numb it. A gentle relaxing medicine may also be administered intravenously to make sure you are comfortable during the surgery. Dilating drops also are applied to give the surgeon access to the cloudy lens.
- The cataract surgeon creates a tiny "side port" incision is made in the cornea and a thick clear ("viscoelastic") fluid is injected into the eye to maintain a safe amount of space between the cataract and the sensitive back surface of the cornea.
- A second small (approximately 3-millimeter) incision is made near the periphery of the cornea for the cataract removal.
- An instrument is inserted in the incision to create a circular opening in the thin sac (called the lens capsule) that holds the lens in place within the eye.
- The phacoemulsification probe is inserted and used to break up the cloudy lens with ultrasonic waves. The pieces of the lens are then removed from the eye with suction, leaving the clear posterior lens capsule intact.
- A soft tube containing the rolled-up flexible IOL is inserted into the eye, and the lens is gently ejected from the tube. The surgeon then adjusts the position of the IOL so it fits securely and properly where the natural lens used to be.
- The viscoelastic fluid is removed from the eye, along with any remaining bits of lens material.
In many cases, no stitches are needed to seal the surgical incision in this type of cataract surgery.
The entire procedure typically is done on an outpatient basis, and generally takes less than 30 minutes. Many patients see well almost immediately after surgery.
Types of Multifocal IOLs
Popular multifocal IOLs that are FDA-approved for use in cataract surgery performed in the United States include:
AcrySof ReSTOR IOL
The AcrySof ReSTOR multifocal IOL (Alcon, Inc., Fort Worth, Texas) received FDA approval in March 2005. The AcrySof ReSTOR lens features a diffraction grating a concentric arrangement of very fine parallel grooves on the surface of the lens that enables it to change the direction of light differently in different lens zones and provide a multifocal correction.
The Tecnis Multifocal IOL, produced by Abbott Medical Optics (Santa Ana, Calif.), received FDA approval in January 2009. It features a full diffractive surface, similar to Alcon's AcrySof ReSTOR IOL.
The ReZoom Multifocal IOL, also produced by Abbott Medical Optics (AMO) received FDA approval in March 2005. The ReZoom lens has five concentric power zones to provide clear vision at all distances. Depending on your visual needs, your brain learns which portion(s) of the lens to use for clear vision.
Multifocal IOL Cost
Multifocal IOLs cost more than traditional monofocal intraocular lenses. Medicare, supplemental insurance policies for people covered by Medicare, and private health or vision insurance typically will not cover the additional cost of these premium IOLs, compared to the cost of standard monofocal lenses used in cataract surgery.
If you choose to upgrade to a multifocal IOL as part of your cataract surgery, usually you will be required to pay "out-of-pocket" the difference in cost between the multifocal IOL and the allowance your insurance company provides for a conventional monofocal IOL.
According to a leading eye care industry analyst, the additional out-of-pocket fee for upgrading from a conventional monofocal IOL to a multifocal IOL is in the range of $1,500 to $2,500 per eye, and can be higher.
Prior to proceeding with cataract surgery, be sure to ask your cataract surgeon and your health insurance representative to thoroughly explain all fees and charges for your procedure, the coverage provided by your policy and any applicable out-of-pocket expenses.
You can lower your out-of-pocket costs to upgrade to multifocal IOLs by setting up a Health Savings Account (HSA) at your bank or contributing to a flexible health benefits program at work.
Many refractive surgeons also offer financing programs that allow you to pay over time at attractive interest rates or interest-free for a limited period of time.
Note: This information is for general education purposes only. It is not to be used as a substitute for medical advice from your eye doctor or refractive surgeon.