Cataract Surgery: Refractive Cataract Surgery

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I’ve Heard Of Refractive Cataract Surgery. What Is That All About?

As already stated, cataract surgery is the safest and most successful surgery performed today. A large part of that success is owed to the tremendous technological advances in the intraocular lens implants and the instruments used to determine the correct implant for your surgery.

The objective of basic cataract surgery is to simply restore your best-corrected vision to its pre-cataract status. Best-corrected implies with glasses if needed. Typically, most cataract patients selecting this approach have their vision improved with a monofocal intraocular lens focused at distance. The power of the lens you require is typically determined by a separate keratometer and ultrasound device. While the quality of your vision is generally excellent, any preexisting astigmatism and any postoperative farsightedness or nearsightedness you have is corrected with glasses. In addition, your vision is limited in its range of focus. If focused at distance, you will need to wear reading glasses or bifocals for near vision and some intermediate vision.

In contrast, the goal of refractive cataract surgery is not only to restore your pre-cataract vision, but also to enhance your vision to minimize your dependence on glasses.

First, refractive cataract surgery typically utilizes an optical instrument such as the Humphrey-Zeiss IOL Master in addition to ultrasound to perform your eye’s measurements. This additional method increases the accuracy and precision of the measurements, which in turn, minimizes your potential for significant farsightedness or nearsightedness after cataract surgery.

Second, your preoperative measurements are augmented with corneal topography, that is, a computerized three-dimensional mapping of your eye’s surface. This allows a full assessment of any preexisting astigmatism in order to plan the appropriate treatment.

Lastly, you may consider a premium toric or multifocal intraocular lens as opposed to a traditional spherical monofocal intraocular lens.

The benefit of a toric lens is that it dramatically diminishes your amount of astigmatism following cataract surgery. If you have pre-existing astigmatism, choosing this lens improves your post-operative vision and allows you freedom from glasses that would otherwise be required to correct your astigmatism after surgery. Typically, you can use non-prescription “over-the-counter” reading glasses for near work.

Our personal favorite toric lens is the ACRYSOF Toric developed by Alcon. The Toric is the newest member of the proven ACRYSOF lens family which are the most commonly used intraocular lenses in the world with over 21 million implanted.

The benefit of a multifocal lens is that it allows you to focus over a range from distance to near, and thus minimizes your dependence not only on distance glasses but also on reading glasses.

The ReZoom intraocular lens made by Advanced Medical Optics is a second generation refractive multifocal lens recently approved by the FDA to provide the desired range of focus. The Crystalens, made by Eyeonics, inc., is technically an accommodating lens purported to accomplish the same goals albeit in a slightly different manner.

Our personal favorite is the ACRYSOF ReSTOR intraocular lens. Also developed by Alcon, the ReSTOR is another member of the proven ACRYSOF lens family.

What distinguishes the ReSTOR is that it provides quality vision over a range from distance to near by combining the two optical properties known as diffraction and apodization.

For you technical buffs, diffraction divides incoming light into multiple wavefronts using small steps on the lens surface. This produces two sharp focal points, one for distance and one for near. Apodization, used for years in telescopes and microscopes to improve image quality, takes the steps of a traditional multifocal lens and gradually reduces their heights from the center of the lens to the periphery. The gradual transition blends the light energy between the two focal points to create a high quality range of vision with minimal to no side effects.

Are There Any Nuances To The Restor I Should Know About?

Yes, if you choose the ReSTOR, it is important to understand that you must allow time to adapt to the multifocal optics of the ReSTOR.

Neuroadaptation is the name of this process where the visual centers of your brain learn to utilize the distance, intermediate and near images of the multifocal ReSTOR. This can be immediate, but usually occurs over a period of several weeks to several months and even improves up to a year out in order to optimize your vision.

In addition, you will notice halos around point sources of light in dark surroundings. This is normal and is due to the multifocal design of the lens. This typically diminishes as neuroadaptation takes place.

Furthermore, the ReSTOR is designed to optimize your distance and near vision. You may notice a slight compromise at intermediate lengths. This also typically diminishes with time.

Lastly, your reading vision with the ReSTOR is best obtained with bright light and good print. Dim lighting and poor contrast print will limit your ability to read as usual and may require reading glasses.

Once neuroadaptation occurs, the lens works very well. Of the original FDA ReSTOR study participants, 80% reported “never” wearing glasses for their daily activities and only 17% reported “sometimes” wearing glasses, mostly for intermediate desktop computer use.

What If I Have Astigmatism But Want The Restor?

If you have astigmatism and are interested in the ReSTOR, your astigmatism must be treated. Treatment options for astigmatism with the ReSTOR may include a simple extra incision or two referred to as corneal relaxing incisions or a more elaborate reshaping approach with an excimer laser as used in the popular LASIK and PRK procedures.
Am I Settling For Less If I Do Not Choose A Premium Lens Such As The Toric Or Restor?

No, absolutely not. First, if you have no astigmatism, the Toric is not indicated. Second, you may not be an appropriate candidate for the ReSTOR.
Third, you benefit from the technology and skills we use to perfect the premium lenses even if you do not choose the Toric or ReSTOR. Most importantly, all of our lenses are state-of-the-art. The descriptive term premium simply denotes those lenses with features that are considered optional and above-and-beyond the standard set by insurance carriers.

If you prefer and/or would most benefit from a traditional monofocal lens, our favorite is the ACRYSOF IQ. Even though it is traditional in a monofocal sense, it is no less advanced than its premium counterparts. Considered a “newer technology IOL” by insurance carriers, it corrects for spherical aberration and thereby provides you the sharpest monofocal vision available.

Can I Read Without Glasses With The Monofocal ACRYSOF IQ?

For our monofocal patients who prefer to read without glasses, you have two options.
The most popular option is monovision. This is where your dominant eye is focused at distance and your other eye is focused at near. While you may notice compromises in near depth perception and night driving without glasses, it is a very acceptable alternative for many, especially those of you experienced with monovision in contact lenses.

A much less popular but occasionally chosen option is to place both of your eyes at near. This obviously requires you to wear glasses for all distance related visual tasks, but it is an excellent option for those of you who are avid readers or hobby enthusiasts who work at near continuously.

Do Cataracts Come Back?

No, your original cataract does not come back. However, your lens implant is held in place by a thin membrane known as the lens capsule. This capsule is the outermost lining of the original cataract. Furthermore, it may become cloudy with time. If it does, it is referred to as posterior capsule opacification or PCO. Fortunately, PCO is easily taken care of by “polishing” away the central cloudiness using a laser in the office. The procedure is known as a “YAG capsulotomy” and is painless. In addition, while it is a procedure and has risks, they are minimal and rarely occur.

I Don’t Have Cataracts. Can I Still Have An Intraocular Lens To Gain Freedom From Glasses?

While the FDA approved the ACRYSOF IQ, Toric, and ReSTOR for the primary implantation in cataract surgery patients, they may also be used for refractive surgery, that is, surgery done to simply provide you freedom from glasses.

The ReSTOR is a particularly good option for those in their 50’s or better who suffer from presbyopia. Presbyopia is the decreased ability of the natural lens to focus over a range of distances that occurs with aging. The condition eventually affects everyone, including those who are nearsighted, farsighted, have cataracts, or had perfect vision most of their life.

The procedure for using an intraocular lens in a patient prior to the development of a cataract is essentially identical, except it is no longer referred to as cataract surgery. Rather, it is often referred to as a refractive lens exchange or clear lensectomy. If you are in this age range and have deferred laser vision correction because of the need for reading glasses, you may now be interested in this potential new visual freedom.