Credit Stuart Bradford
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Two years ago, Anne Collins of Arlington, Va., who has been wearing glasses since fifth grade, noticed she had trouble reading the overhead street signs while driving. Cataracts, the clouding of the natural lenses that occur with age, were taking their toll.
She decided it was time for cataract surgery.
Mrs. Collins, now 61, chose to have her lenses replaced with two different intraocular lenses – one for seeing far and the other for seeing near — in a procedure known as monovision cataract surgery.
“I thought it was a miracle,” Mrs. Collins said after the surgery was completed. “It was like I was back in second grade and didn’t have any problems with my eyes.” Still, her vision isn’t perfect. Mrs. Collins still needs glasses to read the newspaper, but she can see her cellphone just fine.
By age 80, more than half of all Americans either have a cataract or will have had cataract surgery, according to the National Eye Institute. The average age for the surgery is the early 70s.
Cataracts typically develop in both eyes, and each eye is done as a separate procedure, usually one to eight weeks apart. Patients most commonly have their clouded lenses replaced with artificial monofocal lenses that enable them to see things far away. Most will still need glasses for reading and other close-up tasks.
With monovision surgery, the patient’s dominant eye receives a replacement lens for distance vision. In a subsequent operation, the less dominant eye receives a lens for close vision. Once surgery on both eyes is completed, the brain adjusts the input from each eye and patients typically can see both far and near. Some people can stop wearing glasses altogether, although many, like Mrs. Collins, still need them for certain tasks.
But monovison takes some getting used to. The ideal candidates may be people who already have tried a monovision approach with contact lenses for 15 or 20 years, before they even have developed cataracts, said Dr. Alan Sugar, a professor of ophthalmology at the University of Michigan. “People who have worn contact lenses in their 40s, with one contact for near vision and one for distance, are good candidates,” he said.
Others may be able to give monovision a trial run. The cataract surgeon replaces the first eye with a lens that corrects for distance vision and then, if the cataract in the second eye hasn’t progressed too far, can let the patient use a contact lens for near vision in the second eye, Dr. Sugar said. If the patient is comfortable with the trial monovision, the surgeon can then implant a lens for near vision in the second eye.
Experts caution that monovision surgery is not for everyone. “Many patients get misled by asking how their friends like monovision,” said Dr. David F. Chang, a clinical professor of ophthalmology at the University of California, San Francisco, and past president of the American Society of Cataract and Refractive Surgery. “Some individuals hate what another individual loves.”
After any cataract surgery, including monovision surgery, patients may also experience what doctors call “dysphotopsia,” or visual disturbances like seeing glare, halos, streaks or shadows. Moderate to severe problems occur in less than 5 percent of patients, said Dr. Tal Raviv, an associate clinical professor of ophthalmology at the New York Eye & Ear Infirmary of Mount Sinai Icahn School of Medicine. Symptoms often improve during the first three months after surgery without treatment, he said, though in a small number of cases one or both lenses may need to be replaced.
In addition, some patients who get monovision surgery will need a separate pair of glasses that focus both eyes for distance vision for driving at night. “Night driving is more difficult if both eyes are not optimally focused at distance,” Dr. Chang said.
Another option in cataract surgery for those hoping to get rid of the glasses altogether is the use of multifocal lenses, which focus each eye for both near and far viewing, something like the progressive lenses in eyeglasses. In one study of around 200 patients who had either multifocal or monovision cataract surgery, just over 70 percent of the multifocal group could forgo glasses altogether, compared to just over 25 percent of the monovision group.
But patients who undergo multifocal surgery are more likely to have side effects like glare and halos, according to Dr. Mark Wilkins, the lead author of the study and a consultant ophthalmologist and head of clinical services at Moorfields Eye Hospital in London. In his study, six of 94 patients in the multifocal group had to have second surgeries to get replacement lenses, versus none in the monovision group.
Typically, Medicare covers regular cataract surgery and implantation of standard monofocal lenses but does not pay for multifocal lenses, so insurance reimbursements may be limited.
The key to deciding which type of cataract surgery is right for you is to understand your eyes and goals. “Talk about the pros and cons” of each type of cataract surgery, Dr. Wilkins said. “There’s no other way really.”