July 2007

 

CATARACT/ IOL

 

In My Own Hands

Creating the optimal surgical environment


by Farrell “Toby” Tyson, M.D.

 

 

 

The right technology and surgical techniques will ensure your patients are seeing great on post-op day one

My goal has always been to perform the best cataract surgery I possibly can. With multifocal IOL implantation, patient expectations are higher, and the surgeon’s margin of error is lower. These lenses are less forgiving of small power miscalculations or even minor corneal edema or posterior capsular opacification. In short, premium IOLs demand high-precision surgery to give the patient the fastest recovery and the best possible chance of spectacle independence. Others have addressed the critical pre-operative factors, such as patient selection, accurate biometry, and matching the IOL to the patient’s needs. However, it is equally important to pay attention to the surgical environment—to make sure to use the very best technology and techniques in the operating room itself.

The right tools simplify cataract surgery

The most important factor in choosing both phaco technology and in refining one’s phaco technique is to use as little phaco energy as possible. This reduces endothelial loss, improves corneal clarity, and speeds up post-operative visual recovery. I use the AMO Sovereign WhiteStar system (Advanced Medical Optics, Santa Ana, Calif.). Cold phaco with this system reduces phaco energy by about 60%. New ICE (Increased Control & Efficiency) technology further reduces ultrasound energy by using a brief “punch” in the first millisecond of the pulse to accelerate cavitation. For a fast surgeon, this may not make a huge difference, but it can reduce effective phaco time (EPT) for someone who is in the eye longer or when dealing with very dense nuclei. WhiteStar has very good fluidics, so I don’t get any chamber bouncing or “trampolining” of the back of the capsular bag when I am performing in-the-bag phacoemulsification. And, while all the newer phaco systems significantly reduce the chance of a corneal burn, WhiteStar almost eliminates the possibility.

Surgeons who are implanting multifocal IOLs should be performing small-incision surgery with clear corneal incisions. Clearly, we are moving toward even smaller wounds through microincisional surgery. As IOL manufacturers catch up and start making lenses that can fit through smaller incisions, we’ll see a rapid migration to microincisional surgery, but even now it is valuable for ease of placing the incision on the axis of astigmatism and again, reducing phaco energy. In a study I recently conducted, 245 consecutive eyes were randomized to either bimanual WhiteStar phaco or standard coaxial WhiteStar phaco. All variable phaco settings were the same in both groups. With a 3+ nuclei, the reduction in EPT with bimanual surgery was 38.2%. With 2+ nuclei, there was a 51.5% reduction in EPT.

The choice of an ocular viscoelastic device (OVD), while often considered a minor detail, is actually a critical part of cataract surgery. I use Healon5 (sodium hyaluronate 2.3%, AMO), a high molecular weight, high-viscosity, viscoadaptive OVD, on almost all my cataract surgeries except those in which I’m also doing endocyclophotocoagulation (ECP). For ECP and bimanual cases, I prefer the lower viscosity HealonGV (sodium hyaluronate 1.4%). I think some have avoided Healon5 for fear that OVD removal will slow down their surgery day. My average procedure time is only about five minutes. When I converted to Healon5, I actually found that it made me a faster surgeon because every case is the same. The capsulorhexis, cataract removal, and lens insertion are all smooth and predictable. I’m not stressed out or slowed down by mistakes or the need for additional instruments in tougher cases.

Slow and steady technique

I start a case by injecting Healon5 into the anterior chamber. The trick to not overfilling the chamber is to stop injecting when the “worms” of OVD begin to coalesce into a mass. Then I perform the capsulorhexis, which is very controlled with Healon5. I never have to worry that it’s going to tear or run out. In fact, I can actually do a “blind” capsulorhexis in small-pupil cases when I can’t see it beneath the iris. The capsulorhexis is important with any cataract surgery, but especially with a multifocal lens. For these IOLs, you want a nice round, slightly overlapping, 5.5-mm capsulorhexis. For hydrodissection and hydrodelineation, I go in underneath the lip of the capsulorhexis and do a very slow push of the BSS so I can watch the wave go behind the lens and push it forward slightly. I spin the lens to make sure I have a good separation. Then I enter the eye with my phaco tip and let the infusion run for just a second to give me a pocket of separation between the Healon5 and the lens. I hit the phaco power, make a central groove, either chop or groove the lens quadrants, and remove them. The entire time, I’m doing the phacoemulsification down in the bag while the Healon5 is up in the anterior chamber. This gives me very good fluidics and chamber maintenance and completely protects the endothelium from any lens fragments. Usually I’m able to completely remove the cortex just by having a good hydrodissection. About 30% of the time I have to go in and clean up cortex but even then, I don’t worry much about subincisional particles because the Healon5 actually polishes the capsule clean as I inflate the bag for lens implantation. As it’s being injected, the Healon5 again looks like worms, but in this case the worms start falling right through the capsulorhexis into the bag, pushing it open and scraping off any little adherent strands of cortex.

Once again, you want to slowly and deliberately fill the bag prior to lens injection. Healon5 is so viscous that even silicone lenses open up nice and slowly, with no “snap.” When you dial the lens into the bag it actually sits nasally away from you, making it very easy to remove the OVD from behind the lens with the irrigation/aspiration tip. When the OVD is all gone, I pull the irrigation/aspiration tip back towards the wound. You can tell if all the viscoelastic material is gone because the IOL will slide right into the center of the bag.

Healon5 is a powerful tool in more complicated eyes. For example, it will hold a floppy iris in place or allow you to enlarge the iris without using retractors in a small-pupil case. It doesn’t ooze out of the eye at all, even at the major keratome incision. In fact, if I have a wound that is a little bit leaky, I will put a dab of Healon5 behind it to act as a spackle.

Adding up the advantages

Taking advantage of all the incremental improvements in phaco and OVD technology adds up to better results for patients—and that can really set a surgeon apart from the competition. I think the combination of WhiteStar cold phaco and Healon5 is healthier for the endothelium, which may result in more years of better vision. We can’t predict that with certainty, but it makes sense to me that preserving endothelial cells may give patients better contrast sensitivity in the long term.

In the short term, the biggest difference of new-technology cataract surgery has been noticeably clearer corneas on post-op day one. I now expect all my cataract patients to be 20/30 or better the day after surgery, unless there is some retinal or corneal disease. When your patients can see this well, they become your biggest fans and word-of-mouth referrals increase significantly.

Editors’ note: Dr. Tyson reported no financial interests related to his comments.

ABOUT THE AUTHOR

Dr. Tyson is in private practice in Cape Coral, Fla. Contact him at 239-542-2020 or tysonfc@hotmail.com.

Creating the optimal surgical environment Creating the optimal surgical environment
Ophthalmology News - EyeWorld Magazine
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