Multifocal lens implant offers a new option for cataract patients
Some of the 13 million Americans who suffer from cataracts may see again like they did at 40 through the first lens implant to offer patients a range of vision, from near to far. The first significant cataract treatment advance in more than a decade, the AMOArray Multifocal Intraocular Lens from Allergan may make glasses unnecessary for many everyday activities.
The lens implants typically used on cataract surgery are monofocal, dedicated 100 percent to distance vision. The multifocal lens is designed to also provide good focus for a range of near distances necessary for reading or doing crafts.
“It allows the patient to do a lot more without glasses than they could with even their own eye,” said Dr. David Chang, a Los Altos ophthalmologist. “We never had anything like this option for people. It is truly another big step.”
Chang was among 60 physicians nationwide, and the first in Northern California selected by Allergan, to do surgery using the new lens and teach courses in its use. So far he has done nearly 100 surgeries with it at El Camino Hospital in Mountain View.
Cataracts are the leading cause of vision loss among adults age 60 and older. They are caused by an age-related cloudiness in the eye’s natural lens that impairs vision, making everyday activities increasingly difficult.
Modern cataract surgery, where the cataract is extracted, was introduced in 1948 by Parisian Jacques Daviel. The first intraocular lens was devised in England in the 1940s based on discoveries during the treatment of injured World War II pilots.
Monofocal lens implants were fully adopted in the early 1980s and “really revolutionized cataract surgery,” Chang said.
Now, “to be able to see both far and close is really an advance in technology,” agree ophthalmology partners Drs. Daniel Beers and Mark Volpicelli of Mountain View. They, along with Chang and Drs. Bart Carey and David Mark of Silicon Valley Eye Physicians in Sunnyvale, are among those using the lens in surgery at El Camino Hospital.
In clinical trials 41 percent of patients implanted with the AMOArray lens never used glasses, compared to 11 percent of patients with monofocal lenses. For near tasks, 38.4 percent of multifocal patients did not wear glasses versus 9.8 percent of monofocal patients. In addition, 84.9 percent of those receiving multifocal lenses never wore glasses for distance vision, compared with 52.4 percent of those with monofocal lenses.
According to Allergan’s Steve Martin, the AMOArray lens uses multiple concentric rings of varying optical power, with several zones that provide vision over a range of distances. The center of the lens is fully dedicated to distance vision. This design renders the lens more akin to the eye’s natural lens than monofocal intraocular lenses.
However, both physicians and Allergan caution, there are disadvantages. According to an Allergan spokesperson, the possible decrease in the use of glasses may come at the cost of losing some of the sharpness of vision, especially under poor visibility conditions such as low light or fog. Chang and Beers also spoke of a “halo effect” that could occur with night driving or other bright/dark contrast situations.
“It’s not a perfect lens,” Beers said. “You can still wear glasses to improve your vision or in dimmer light.”
Chang emphasized that the multifocal lens is not right for everybody. “About one in five of my patients are good candidates,” he said. “The ideal candidate has two cataracts now or will need a second implant down the road.”
People with additional eye problems, such as glaucoma or macular degeneration, or who have already had a conventional lens implant, are not good candidates for a multifocal lens, Chang said. Also, those who are extremely nearsighted, have a lot of astigmatism or very small pupils, “the multifocal lens is not for you,” he said.
Chang said even good candidates might still continue to use glasses for prolonged reading or computer viewing.
The doctors also said that new technology is just one part of the cataract treatment package. “The key is getting the right (lens) power,” Volpicelli said. Powers are the required focus strengths for each eye. With glasses or contact lenses, patients help determine the right powers through tests made during an eye examination.
“Each eye is unique,” Chang said. “There are 40 possible powers. With a lens implant there is no chance for trial and error as there is with glasses or contacts. We use a computer program to determine the right power.”
Beers, Chang and Volpicelli recommend consulting with your ophthalmologist about the best lens choice well in advance of surgery.
“It’s important for the patient and physician to have realistic expectations,” Beers said.
For more information on Allergan’s multifocal intraocular lens talk with your ophthalmologist.
