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Making the Case for Microincisional Cataract Surgery
Existing phaco techniques are already very safe and effective. How much difference could a few tenths of a millimeter make?
Irene Tsikitas
Publish Date: May 7, 2011   |  Tags:   Ophthalmology

Current phacoemulsification techniques, typically performed within a sub-3mm incision requiring no sutures or stitches, have gotten so good that cataract surgery today is associated with very high success rates (estimated around 95%) and very low complication rates among patients without other existing eye conditions. So, if it ain't broke, why fix it? That's the question you may be asking yourself when you consider the push for microincisional cataract surgery — phacoemulsification performed within incisions as small as 2.2mm to 1.8mm. Let's explore some questions associated with the quest for tinier and tinier phaco incisions.

What does "microincisional' mean?
There's no standard definition of a "microincision" for phacoemulsification. When folding lenses let surgeons go from a 3mm or 3.5mm incision down to 2.4mm or 2.5mm, "that was a really big step at the time," says David Brown, MD, FACS, founder and medical director of the Eye Centers of Florida in Fort Myers. But today, when most people say "microincisions" for cataract surgery, they're talking smaller than 2.4mm, typically in the 2.2mm to 1.8mm range (1.8mm being the smallest phaco incision through which you can implant an IOL without further enlarging the wound, depending on the system you use).

Richard Hoffman, MD, clinical associate professor of ophthalmology at Oregon Health and Science University's Casey Eye Institute, says that while incisions that small are new to most U.S. ophthalmologists who use the coaxial phaco technique, they're standard practice for surgeons like him and his partners at Drs. Fine, Hoffman & Packer in Eugene, Ore., who use the bimanual technique. "We do everything through a 1.2mm incision or 2 1.2mm incisions," says Dr. Hoffman, referring to the phacoemulsification and irrigating processes. "Then when we put the lens implant in, we make a third incision" sized between 2mm and 2.5mm. With the coaxial technique, surgeons have begun to do all those steps through a single small incision (though not as small as 1.2mm). To get used to the change, Dr. Brown says he started with the bimanual technique to get the hang of phacoemulsification and irrigation through a smaller incision, then switched back to the coaxial technique once he was over the learning curve. "Bimanual can be an intermediate step when trying to get a smaller incision," says Dr. Brown, although ultimately he prefers the coaxial microincisional technique, now that today's phaco systems have made it possible.

Why smaller incisions?
Cataract surgery today, most often performed through an incision around 2.5mm, give or take, is incredibly safe and efficient, with a very low incidence of complications such as surgery-induced astigmatism or infection. Does shaving a few more tenths of a millimeter off the incision size really make that big of a difference? Yes, argue advocates, who believe that if you have the technology, smaller is always better. "There's a noticeable difference with how quickly the eye stabilizes after surgery," when you go down to a 2mm or sub-2mm incision, says Dr. Brown. "It's better for patients," adds Uday Devgan, MD, FACS, FRCS, chief of ophthalmology at Olive View UCLA Medical Center. "There's no question smaller incisions are better."

Microincision enthusiasts say the benefits of going smaller include:

  • less trauma to the eye,
  • less surgically induced astigmatism,
  • less inflammation and risk of infection, and
  • faster wound sealing and healing.

Of course, these are the same advantages realized when surgeons went from 3mm or greater incisions down to sub-3mm. If your ophthalmologists are still getting great results, they may see little need to change. "When you start getting below 2.5mm, the advantages are really miniscule," says Dr. Hoffman. "Its more hype than functionality." He worries that there may be a detriment to implanting IOLs through smaller incisions: the quality of the lenses themselves. "The lens technology is way behind what we can do with the incisions," he says. "Those lens implants [that can be inserted through smaller incisions], because of the way they're designed, I think their stability in the eye is not as good as a lens that's going through a larger incision."

Early adopters like Dr. Brown and Dr. Devgan don't have any complaints about the lenses and see microincisions as the "evolution" of cataract surgery. Gina Stancel, HCRM, CST, COA, surgical administrator at Dr. Brown's Eye Centers of Florida, says it's largely a matter of whether your surgeons are eager to adopt the latest technology, although she adds there may be a "keeping up with the Joneses" benefit. "It's very competitive to push that smallest incision," she says.

New equipment and supplies
Will a smaller phaco incision impact your cataract case costs? Here are the items that Ms. Stancel says you may need to change:

  • Knives and forceps. Ms. Stancel's ophthalmologists use diamond knives, so converting to microincisional cataracts required an investment in a whole new set of smaller blades to make those 2mm or smaller incisions. It was a significant initial outlay, but "once it's changed, it's changed," she notes. Dr. Devgan says you may also have to upgrade your trays to newer capsulorhexis forceps that will go through a smaller incision.
  • Lenses. You'll need folding lenses that can be inserted through incisions 2.2mm or smaller, which Ms. Stancel says don't cost more than what you'd use for a 2.4mm or 2.5mm incision.
  • Phaco needles, tips and sleeves. If you're buying microincisional cataract supplies from the same company that already supplies your lenses and phaco packs, the cost of switching to sizes that will accommodate your smaller incisions should be relatively comparable, says Ms. Stancel. "You will need new tips, sleeves and needles, but they should not cost more than what you're already paying" for larger incision supplies.

The good news is, you don't necessarily need a new phaco machine to do sub-2.4mm incisions, depending on the model you currently have and how small your surgeons want to go with their incisions. Bausch & Lomb's Stellaris system is the only one that lets the surgeon implant the IOL through a sub-2mm incision (1.8mm), but Alcon's Infiniti system is "very amenable to a 2.2mm incision," says Dr. Devgan, who is a paid consultant/speaker for both companies, as well as for Abbott Medical Optics. AMO introduced its own Micro-Implantation Cataract Suite at the American Society of Cataract and Refractive Surgery Symposium and Congress in March. The company says the system is "designed for as little as a 2.2mm incision through an assisted technique."

Dr. Devgan recommends that you take all the new machines for a test drive, just to see what their "subtle differences" are and whether your surgeons feel it's time for an upgrade. The key is to ensure your machine can adjust to the different parameters, such as fluidic control, needed when you're working within a smaller incision. For microincisional cataract surgery to achieve its purported benefits, says Ms. Stancel, "you've got to have a good phaco machine behind it."

Are smaller incisions inevitable?
Not long ago, removing cataracts and implanting IOLs through an incision smaller than 3mm was considered a huge step. Now it's the norm. Five or 10 years down the road, will we be saying the same about 2.2mm to 1.8mm incisions? Dr. Devgan says while he certainly doesn't see the pendulum swinging back to larger incisions, he does feel "there's a point of diminishing return, a point where the incision gets too tiny" and could actually slow down the procedure. "2mm, plus or minus, is kind of our sweet spot," he says. But with another major innovation on the horizon — femtosecond laser cataract surgery — Dr. Brown believes it may one day be possible to go even smaller than 1.8mm with coaxial phaco systems. "I can't tell you if a 1mm incision is going to be better than 1.8," he says, "but chances are it probably will."