Intraocular Lenses

Intraocular lenses, (also know as “IOLs”), are the artificial lenses that we implant on the inside the eye to replace the optical power of the natural lens that is removed during cataract surgery. In 1981 the FDA approved the first IOL for use in the US. Prior to then, there were no artificial lenses available to put back on inside the eye when the natural lens was removed. In order to see clearly, and make up for the lost optical power, people had to wear very thick glasses or wear special contacts after surgery.

Recently, many types of IOLs have been introduced to help with many types of vision problems, and now, more than ever, patients are becoming more involved in selecting the type of IOL that might best suit their needs.

The following is meant to be a simple guide to help you when you and your doctor are selecting the type of IOL that may be most appropriate for your needs. It is not and exhaustive list of IOLs, nor does it include an exhaustive list of advantages, disadvantages, risks and or benefits of each IOL or for cataract surgery in general. For further information please talk with your surgeon at Kitsap Eye Physicians.

Aspheric IOLs

Aspheric IOLs were first introduced in 2004 and utilize modern wavefront* technology to help reduce many of the optical aberrations not addressed by traditional IOLs.. Aspheric IOLs can provide better contrast sensitivity than traditional spherical IOLs., allowing better overall vision especially in dimly lit settings, rain, and fog. The Tecnis IOL, by Advanced Medical Optics, was the first IOL to receive FDA approval for this new type of advanced technology. Alcon Makes the monofocal AcrySof SN60WF and the new aspheric version of the multifocal AcrySof ReStor. Both lenses incorporate Alcon’s blue light-blocking feature (see below). Bausch & Lomb makes the SofPort Advanced Optics IOL. A clinical study using a night driving simulator was the basis for the FDA’s approval of the first ashperic IOL.

(*Wavefront is the technology used in modern personalized custom LASIK procedures to help reduce the higher order aberrations that can decrease the overall quality of vision )

IOLs to help reduce your need for reading glasses:
ReZoom, AcrySof ReStor and Crystalens

Traditional IOLs are monofocal, meaning they can provide sharp vision within on certain range (far, intermediate, or near). Typically, people with this type of IOL will need reading glasses or bifocals to meet most of their visual needs. Modern multifocal and accommodating IOLs can help provide good vision for distance and near, reducing ones dependence on glasses. There are several types of IOLs in this category. A few of the more popular ones are listed below.

The ReZoom is a multifocal refractive IOL that has five optical zones to provide near, intermediate, and distance vision. It was approved by the FDA in March 2005. In a European study of 215 patients, 93 percent of ReZoom recipients reported never or only occasionally needing glasses.

The AcrySof ReStor uses diffractive technology to provide near and distance vision. Clinical studies used to support the March 2005 FDA approval showed that 80 percent of people who received the lens didn't use glasses for any activities after their cataract surgery; 84 percent who received the lens in both eyes had distance vision of 20/25 or better, with near vision of 20/32 or better.

The Crystalens was approval by the FDA in late 2003. It was designed to restore the eye's accommodation ability. Accommodation is the ability of the eye to change focus back and fourth from distance to near like most people do before ending up in reading glasses. When people lose this ability it is called presbyopia. It usually begins around age 40, and is thought to be due to the lens inside the eye becoming less flexible. Since the lens has more difficulty changing shape, the ability to focus at different distances is gradually lost.

There are factors that can decrease satisfaction with these IOLs. Some patients experience nighttime halos, glare and starbursts. Also, residual astigmatism and a residual prescription for glasses can be problematic for some people, and may require further procedures to optimize the outcome.

But even with these risks, these new IOLs do provide the probability of good vision without total dependence on eyeglasses or contacts. You may even achieve good vision without using these aids at all.

A brief note on Monovision

If your cataract surgery will likely be done in both eyes within a short period of time, you might consider monovision. It involves implanting an IOL in one eye to provide near and or intermediate vision and an IOL in the other eye to provide distance vision. A few people may have trouble adjusting, but usually people can adapt with time. If you can't, you may still need to wear spectacles to correct the imbalance. Another problem is that fine depth perception may decrease when not wearing glasses because there is less binocular vision. As with the new multifocal IOLs, monovision does provide the probability of good vision without total dependence on eyeglasses or contacts. You may even achieve good vision without using these aids at all.

Toric IOLs for Astigmatism reduction

Toric IOLs are designed to reduce astigmatism. The Staar Toric Intraocular Lens was FDA-approved in 1998, and was the first toric IOL available in the U.S. It can help reduce astigmatism up to 2.4 diopters. Alcon’s AcrySof Toric IOL was FDA approved in September 2005. It also contains the blue light absorbing chromophore as Alcon’s other IOLs (see below). These lenses must be rotated into the proper axis during surgery. Further surgery to reposition or replace the IOL may be required if the lens rotates out of position.

Mild degrees of astigmatism can be treated with limbal relaxing incisions (LRI), which involves making incisions in the peripheral cornea. Higher levels of astigmatism often require the use of toric IOLs, possibly with additional incisional techniques, to reduce astigmatism enough to try to achieve spectacle independence.

Blue/Violet Light-Filtering IOLs

The AcrySof Natural, in addition to filtering ultraviolet (UV) light, similar to most other IOLs, also filters high-energy blue light. UV rays have long been suspected to cause many eye problems, and most IOLs filter them out just as your natural crystalline lens does. Blue light, which ranges from 400 nm to 500 nm in the visible light spectrum, may cause retinal damage and may contribute to age-related macular degeneration. The AcrySof Natural is tinted a faint yellow due to its blue-light absorbing chromophore, and in theory, may help prevent such retinal damage. According to the manufacturer, the yellow tint doesn't alter your color perception or your quality of vision. The SofPort Advanced Optics IOL now incorporates a violet absorbing chromophore that, like the AcrySof Natural, may help protect the retina.

Cost Considerations

The cost of cataract surgery and the implantation of a traditional IOL are typically covered by most insurance plans including Medicare. However the cost of many newer technology implants, the cost of some of the additional testing and procedures unique to their implantation, as well as most astigmatism precedures are not currently covered. Since the benefits of many newer IOLs are not felt to be medically necessary by most insurance companies, they do not typically cover the additional costs associated with their implantation. The patient is responsible for the difference, which could be anywhere from $200 to $2,500, depending on the IOL or procedure.