As more Americans age and require glasses, manufacturers are developing a variety of new lenses that can be placed in the eye that act more like the normal eye.
“We are seeing more and more options,” said John Vukich, MD, associate professor of ophthalmology at the University of Wisconsin. “Patients simply are expecting more out of medicine. They fully expect to see well and expect the technology.”
Vukich and other eye specialists spoke at a news conference here during the American Academy of Ophthalmology Annual meeting.
They said the latest advances in intraocular lenses include implantable lenses with optic zones that allow a person to see up close and at distances, and accommodating lenses that automatically adjust to the needs of the eye.
There are also new lenses -- not yet on the market -- that allow an individual to change the depth of vision with a tilt of the head.
Each year there are 2.4 million surgeries to remove an aging cloudy lens (cataract) and insert an intraocular lens (IOL), Vukich said. With the new multifocal IOLs patients are able to get more than one focus, allowing patients to see close up and at a distance.
“The hot topic here is the multifocal intraocular lenses,” said David Chang, MD, clinical professor of ophthalmology at the University of California, San Francisco.
No More Halo Effect
Although the initial multifocal IOLs often produced a halo, the most recent lenses have less halo effect and have improved close-up vision, he said. Chang cited Advanced Medical Optics’ ReZoom lens, which provides distance vision, intermediate vision, and close-up vision through five different optic zones.
Studies show that after lens implantation, 92 percent of patients only occasionally needed glasses with 93 percent having intermediate vision and 81 percent near vision. “Patients basically are spectacle independent,” he said.
Another multifocal lens -- Alcon’s ReSTOR -- provides good enough vision that in studies 80 percent of patients could put away their glasses and 17 percent only had to wear glasses at times, Chang said.
The advantage of the multifocal IOL is that vision is improved without having to wear glasses, he said. “That is the convenience of these lenses. You can read price tags at the store, read menus, labels, and work on the computer.”
Correcting Close-Up Vision
The latest use of the lens also is to correct presbyopia, when most individuals in their 50s start requiring reading glasses for close-up vision, he said.
However, he warned that not all cataract patients are good candidates for these intraocular lenses and that the out-of-pocket costs to a patient aren’t small.
Eyeonics now offers what the company refers to as its Crystalens; it’s an accommodating lens where there isn’t a division of light, as in the multifocal lens.
Howard Fine, MD, of Oregon Eye Associates, said the accommodating lens offers a better quality of vision than most lenses after surgery to remove cataracts. The lens is designed to mimic the healthy eye’s natural process of accommodation, focusing on objects nearby and at a distance as needed.
Studies haves shown that 71 percent of patients receiving this type of lens have 20/20 vision at near range without glasses, he said, adding that 96 percent end up with at least 20/30 vision at distance.
Improving Intermediate Vision
The patients can see multiple distances and 73 percent are spectacle independent, Fine said. Additionally, 98 percent of patients had good intermediate vision, “something you can’t underestimate in this age of computers.”
The Crystalens sits in the back of the eye and is placed with an injector into the eye through a small incision, he said. “It is especially good for taller individuals, who are further away from their reading material.”
Another type of lens that is increasing in popularity is called the phakic intraocular lens, an implantable contact lens that can be placed in the eye without removing the natural lens of the eye, Vukich said.
The FDA has approved these lenses for the correction of nearsightedness (myopia). Nearsighted people can see near objects well, but far away objects are blurry. With these types of lenses “virtually all of patients” can see uncorrected with glasses, Vukich said. “This is what is driving the market.”
There is expected to be a big growth in the use of these types of lenses with estimated projections of 100,000 implanted by 2009, Vukich said.
And there are more improvements on the horizon, said Fine.
In the pipeline are new lenses with duo opticals that have two flexible lenses, new lenses to take away the edge effect, light-adjustable lenses, and fluid-based lenses that with a tilt of a head result in fluid moving within the lens to increase the power, he said.
By Linda Little, reviewed by Louise Chang, MD
SOURCES: American Academy of Ophthalmology Annual Meeting, Chicago, Oct. 15-18, 2005. John Vukich, MD, associate professor of ophthalmology, University of Wisconsin. David Chang, MD, clinical professor of ophthalmology, University of California, San Francisco. Howard Fine, MD, Oregon Eye Associates. FDA web site.