—Addressing presbyopia through surgery is no easy task, as optometric practitioners know. It’s hard to correct presbyopic refractive errors without sacrificing vision in other areas.
But demand for more advanced treatment options for presbyopia is increasing, says Bill Tullo, OD, FAAO, Optometry Times
Editorial Advisory Board member at Vision West Expo 2016. He and Jim Owen, OD, FAAO, discussed the current methodologies for surgically addressing presbyopia and new technologies that are shaping the process.
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Current strategies for vision correction of presbyopia are still somewhat limited—most surgical methods involve monovision, intraocular lens (IOL) implants, ablative therapies, or corneal inlays. Monovision correction has been the standby for years and has been the cause of much frustration from patients unwilling to lose their near vision for the sake of distance correction. Early IOL options also suffered drawbacks from their close focal points that made moderate vision difficult.
The bottom line is that there is no easy answer for how to correct presbyopia without compromising vision in another area. Fortunately, new technologies and strategies are being developed that may change the way optometrists—and their patients—consider presbyopia.
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Among the emerging trends in refractive correction is the push toward bilateral surgery.
“For the most part cataract surgery in the U.S. is still done one eye at a time,” says Dr. Tullo. “And because of that, you have this decision point after the first lens is put in; what do you do with the second eye?”
He said that his own patients did better when both eyes were corrected at the same time, and Dr. Owen agrees.
“Patients tolerate it much better,” Dr. Owen says.
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Bilateral surgery has been avoided in the U.S. . due to cost and legal barriers, but Dr. Tullo predicts that the profession will see an increase in bilateral surgery in the near future.
“Most people think there’s going to be a dramatic shift toward bilateral cataract surgery in the next five years simply because of cost,” Dr. Tullo says. “You just can’t afford to keep doing it one eye at a time…cost is going to override the litigation concerns.”
This reduction in cost and improved convenience may open the doors for more patients considering surgery, more demand for effective treatment options, and better refractive outcomes down the line.
Cataracts and refractive IOLs
Cataract surgery is one of the most common optical surgeries performed, and cataracts affects patients as they age. This mirrors the progression of presbyopia, which can continue developing until around age 65. Joint treatment of cataracts and presbyopia is emerging goal for both patients and practitioners alike.
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“Cataract surgery has become refractive surgery,” says Dr. Tullo, “and the patients having cataract surgery are a lot younger, and many of them have had refractive surgery. So, their expectations for cataract surgery are no different than they are for LASIK or PRK.”
Dr. Tullo says patients are increasingly expecting 20/20 vision from their treatments rather than settling for imperfect vision.
This highlights the primary challenge for optometrists with presbyopic patients: Getting all patients as close to 20/20 vision as easily as possible while accounting for any other optical problems the patient may have.
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New IOLs are changing the game.
“The nice part about these lenses is less of a risk of dysphotopsias,” Dr. Tullo says. “All IOLs can give dysphotopsia: bifocal, accommodating, diffractive. Diffractive IOLs tend to get more. The nice part about these lenses is you don’t have a diffractive gradient on there. Refracting through it is very, very simple. It’s a little easier to handle.”
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One of the newest IOL options in the U.S. is Tecnis Symfony (Abbott Medical Optics), a marked improvement on past multifocal lenses, according to Dr. Tullo.
“We’ve been using it in our Canadian center now for about three years,” he says, “and this indeed a step beyond the multifocals that we’ve had in the past.”
Tecnis Symfony is the first lens to be approved by the FDA for both sphere and toric use.
“The trick is, it’s using diffractive optics as well as changing chromatic aberrations to extend depth of focus,” says Dr. Owen.
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Corneal corrections for presbyopia are also available, though they must be used cautiously.
“Most of the corneal corrections for presbyopia have really disappeared because efficacy and safety have not been there,” Dr. Tullo says. Although options like multifocal LASIK and multifocal PRK have disappeared, corneal inlays are still effective options.
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Tullo describes three primary methods for corneal inlays:
• Raindrop (ReVision Optics)
The newest option to receive FDA approval, Raindrop is a refractively neutral implant designed to change the shape of eye. When placed in flap or pocket, the lens alters the architecture of the front of the cornea to make it more aspherical.
“Centration is critical,” says Dr. Owen.
Despite its efficacy, some patients may be limited by pupil size.
“This does depend on having a reasonable sized pupil,” Dr. Tullo says, later noting that patients with less than 3 mm pupils may see reduced benefits.
• Kamra (AcuFocus)
Kamra’s pinhole design uses a small aperture to create an extended range of focus. The Kamra design received FDA approval last year, though Drs. Tullo and Owen note that its effectiveness is dependent on the patient’s prescription.
• Flexivue (Presbia)
Flexivue lens works like a concentric multifocal—a hydrogel lens is placed deep in the cornea in the center of the patient’s visual axis in his non-dominant eye. Dr. Tullo says that Flexivue is not FDA approved and likely wouldn’t be for at least two more years.
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Presbyopia and surgery
Although presbyopia has historically been a challenge to address through surgery, the industry is looking to technology for improvements.
Each of these new surgical and implant technologies broaden the scope of patients who may be candidates for refractive therapy. Cost of these treatments varies, and practitioners must be careful to select candidates carefully. The success of each solution is dependent on each patient’s individual refractive and physiologic factors. The efficacy of these early therapies will set the stage for further research into this developing field.