This article is more than 5 years old. Information may no longer be current.
Microincision cataract surgery closer to becoming a reality
New microlenses will allow both photolysis and low-ultrasound phaco to be performed without enlarging the incision, a surgeon says.
Click Here to Manage Email Alerts
ALICANTE, Spain – Microincision cataract surgery is a dream that is about to become true, with the help of the Dodick Photolysis system, new phaco techniques and instruments and the latest developments in IOL technology, according to a surgeon here who has pioneered the technique.
“We have achieved the goal of high-quality, minimally invasive surgery, with maximum surgical control, wound stability and optimal results. The entire procedure of cataract extraction can be carried out through an incision of 1.5 mm or less, without enlarging it at the stage of IOL implantation,” said Jorge L. Alió, MD, PhD.
New instruments
|
|
Prof. Alió has developed his own set of microinstruments for microincision cataract surgery (MICS), produced by Katena Products. They are specially designed for bimanual surgery, as separate irrigation and aspiration is essential to minimize incision size and control the stability of the incision. The new probe is easily inserted through small ports without producing tissue distortion. Intraocular forceps and manipulators can also be used through a 19-gauge incision.
Regarding the type of phaco energy, Prof. Alió is open to different solutions.
“The goal is not that of using one or another type of energy, but operating through the smallest incision possible,” he said.
For cataracts up to grade 3 nucleus hardness, he likes using Dodick Photolysis, a pulsed Q-switched Nd:YAG (1064 nm)-based technology.
“It was through photolysis that I was introduced to the concept of MICS. The Dodick Photolysis system (A.R.C. Laser AG) works well, delivering a very small amount of energy. I had rewarding results with cataracts up to grade 3, and I am convinced that future lasers will develop a better capability of dealing with harder nuclei,” he said.
Low ultrasound
With harder cataracts, ultrasound energy is still the best choice, according to Prof. Alió. The breakthrough in reconciling ultrasound with small incision was using sleeveless phaco tips.
“We quickly understood that every type of phaco tip with bimanual I&A and adequate modifications of phaco settings could be used without a sleeve, thus reducing the incision to the size of photolysis,” he said. “Without a sleeve, the phaco tip delivers more energy into the eye, with a stronger shock wave, but we can appropriately reduce the energy, increase the vacuum and the I&A flow rate so that no thermal burns are produced at the incision site. A constant fluid leakage out of the incision refrigerates the tip and protects the tissues.”
Initially he used a regular phaco machine with a standard phaco tip. Later he found that the 1.2-mm sleeveless tip of the Accurus Mackool system (Alcon) better suited his requirements. The small diameter is perfect for small-incision surgery, and a polymer coating surrounding the tip prevents friction of the phaco probe with the tissue under water, which would otherwise increase the temperature and create a spraying effect that disturbs surgical maneuvers.
Further, the Accurus ABS system prevents surge and improves chamber stability and control of the fluidics in case of occlusion.
“My settings with the Alcon Accurus and the Mackool tip are 30% phaco power, 90 mm Hg of pressure inside the eye and a vacuum of 250 mm Hg. With these settings you can remove any type of cataract, especially if you are using the irrigating chopper and my other instruments. With other phaco machines you’ll have to increase the aspiration to double than normal, keeping the phaco power very low, around 20%, with two pulses per second. If you are using the venturi pump, set it at 300 mm Hg,” he said.
The new IOLs
| Advantages of microincision cataract surgery |
|
Prof. Alió also recommends the use of Healon 5 (sodium hyaluronate 2.3%, Pharmacia), which is a good viscoelastic for MICS because it is dispersive and cohesive at the same time.
“I don’t use it for implanting the lens; I prefer methylcellulose, which is quicker to remove,” he said.
Prof. Alió has tried out two micro-lenses that are not yet commercially available, the ThinOptX (ThinOptX) and the AcriSmart (Acri.Tec). These hyperfoldable IOLs are dehydrated during folding, then rehydrated with the eye’s natural fluids after implantation.
“They can both be inserted through 1.5-mm incisions, and have excellent optical qualities,” he said. “The Thin-OptX has a very thin profile, rolls up into its specially designed cartridge and can be implanted through a 1.6-mm incision. Without the injector the incision can be even smaller, but implantation is more cumbersome and I strongly suggest the use of the injector, especially for beginner surgeons. This lens is also an excellent platform for developing a multifocal model in the future.”
The AcriSmart, on the other hand, has a classic design and is comfortable to use for the surgeon. With the injector, it can be implanted through a 1.5-mm incision.
The two lenses are presently in clinical trials. Which one is best is still difficult to tell, Prof. Alió said.
“Either by using laser or ultrasound, I now treat all my cases with MICS and use as many microlenses as possible, although they are not commercially available. With other lenses, I enlarge the incision, but this will be a thing of the past for all of us in a short time,” he concluded.
For Your Information:
- Jorge L. Alió, MD, PhD, can be reached at Instituto Oftalmológico de Alicante, Adva, Dénia 111, 03015 Alicante, Spain; +(34) 965-150-025; fax: +(34) 965-151-501; e-mail: jlAlió@oftAlió.com. Dr. Alió has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
- Acri.Tec GmbH, manufacturer of the AcriSmart IOL, can be reached at Lindenstrasse 22/24, D-16548 Glienicke b. Berlin, Germany; +(49) 330-56610-0; fax: +(49) 330-56610-10; e-mail: info@acritec.de.
- Alcon Laboratories, manufacturer of the Accurus System, can be reached at 6201 South Freeway, Ft. Worth, TX 76134 U.S.A.; +(1) 817-293-0450; fax: +(1) 817-568-6142; Web site: www.alconlabs.com.
- A.R.C. Laser AG, manufacturer of the Dodick Photolysis system, can be reached at St. Gallerstr. 161, 8645 Jona, Switzerland; +(41) 55-2255011; fax: +(41) 55-2255010; e-mail: sales@arclaser.com.
- ThinOptX can be reached at PO Box 784, Abingdon, VA 24212 U.S.A.; +(1) 276-623-2258; fax: +(1) 276-623-5661; e-mail: ThinOptX@naxs.net; Web site: www.thinoptx.com.