A cataract is simply a cloudy lens inside the eye. Cataracts commonly develop as a result of aging, but they can also be caused by disease, trauma and certain medications.
Options for Rehabilitation of Vision after Cataract Surgery and Refractive Lens Exchange
Understand that the primary goal of cataract surgery is to remove the cloudy lens (the cataract) and replace it with a clear lens (the intraocular lens [IOL] or “implant”). Replacing the cloudy lens with an implant allows the eye to regain its potential for vision. In order to get the best vision after cataract surgery, it is often necessary to wear glasses or contact lenses. The vision obtainable with glasses or contact lenses after surgery is what we call “Best Corrected Visual Acuity” (BCVA).
A secondary goal of cataract surgery is to reduce your dependence upon glasses and contact lenses. Because of recent advances in IOL technology, as well as technology used to measure the eye and plan surgery, we can often make our patients less dependent on eyeglasses. Some patients are able to eliminate glasses entirely, although it is impossible to guarantee with any of these technologies that you will be able to function without glasses for all tasks.
For patients without clinically significant cataracts who undergo Refractive Lens Exchange, the goals are somewhat different. Because these patients already have adequate vision with glasses (whereas cataract patients do not), the primary goal of Refractive Lens Exchange (also called “Refractive Lensectomy” or “Prelex”) is to reduce your dependence on glasses and contact lenses. Understand that although most of our patients who undergo Refractive Lens Exchange will have decreased dependence on glasses and contacts, it is impossible to guarantee that you will be able to function without glasses for all things.
Whether you are having Cataract Surgery or are undergoing Refractive Lens Exchange, you have three basic options for correcting your vision with surgery:
1) Aim for distance vision in each eye using a monofocal lens
This is the option that most of our patients choose. It uses the tried and true technology of monofocal IOL’s that has been developed with great success for over 50 years. Using the sophisticated technology of the Zeiss IOL Master and A scan ultrasound to measure the eye, along with third generation formulas to calculate lens powers, well over 90% of our patients with otherwise healthy eyes will achieve vision that is 20/40 or better—good enough to pass a drivers’ license test without glasses in any state in the country.
Patients with monofocal lenses and good distance vision generally require reading glasses or bifocals to see up close. Reading glasses have the virtue of being inexpensive (generally around $10) and readily available without a prescription.
Monofocal lenses are covered by Medicare and private insurance. If you also have astigmatism and wish to have it corrected at the time of cataract surgery, this can be done. Understand that Medicare and most private insurers do not cover the costs of surgery for astigmatism and that this represents an additional expense.
2) Aim for monovision with monofocal lenses
With monovision, we typically aim for distance vision in the dominant eye. We aim for reading vision in the non-dominant eye by making it nearsighted. Having one eye set for distance and one eye set for near increases the number of things that you can do without glasses. Monovision after cataract surgery or refractive lens exchange works best in patients who have previously worn contact lenses for monovision.
The disadvantage of monovision is that both eyes no longer work together for distance or near vision. Some patients, realizing the advantage of increased freedom from glasses and contacts, tolerate this disparity extremely well. Other patients are unable to tolerate the imbalance between the two eyes.
The monofocal lenses used to create surgical monovision are covered by Medicare and private insurance. If you also have astigmatism and wish to have it corrected at the time of cataract surgery, this can be done. Understand that Medicare and most private insurers do not cover the costs of surgery for astigmatism and that this represents an additional expense.
3) Aim for both near and distance vision in each eye with multifocal lenses
Multifocal lenses offer the best potential for reducing your dependence on glasses and contact lenses after Cataract Surgery or Refractive Lens Exchange. Our practice has extensive experience with multifocal lenses dating back to 1997. Multifocal lenses work by providing simultaneous near and distance vision in each eye, thus allowing both eyes to work together for both distance and near. In 2005, the FDA approved two new multifocal IOL’s with advanced optics having fewer aberrations than previous multifocal IOL designs such as the Array. Each of these designs has relative strengths and weaknesses as follows:
- The Restor lens: manufactured by Alcon, the Restor lens provides excellent distance and reading vision. Its intermediate vision (computer screens, etc.) is not quite as good as the distance and reading vision typically achieved by most patients with this implant.
- The Rezoom lens: manufactured by AMO, the Rezoom provides excellent distance and intermediate vision, and good near vision.
Weaknesses inherent in all multifocal IOL designs include aberrations that can cause glare and halos, especially at night. About 1 in 20 patients describe the glare and halos with multifocal lenses as “severe.” Multifocal lenses work best with binocular vision (both eyes working together), therefore, you will not get the full effect of multifocal vision until you have had surgery on your second eye.
Although multifocal lenses may represent your best option for reducing your dependence upon glasses and contact lenses, it is impossible to guarantee that you will be able to throw away your glasses. Reading glasses, for instance, will always magnify near objects, thus making them easier to see, even with multifocal lenses.
Because Medicare and private insurance companies generally consider multifocal lenses to represent a luxury technology that is not absolutely necessary for good vision, multifocal lenses are not covered by Medicare and insurance.
A Few Words Regarding Intraocular Lens Power Calculations
Although the techniques we use to measure the eye and calculate IOL powers are state of the art, they are not perfect. We make every effort to ensure that our patients’ refractive results are as intended. Because of some inherent limitations of these technologies, a small percentage of patients may have an unpredictable outcome after surgery, especially in patients who have had prior refractive surgery such as RK, LASIK, or PRK. Regardless of the option you choose for rehabilitating your vision after cataract surgery or refractive lens exchange, understand that further surgery such as PRK, LASIK, intraocular lens exchange, or YAG laser capsulotomy may be required to fine tune your vision.
Remember that all of the options presented above represent efforts to reduce your dependence upon glasses and contact lenses. None of these options can guarantee you to throw your glasses away. Talk with us about which of these options might be best for you.