September 2019

CATARACT

Device Focus
Broad usefulness of miLOOP, surgeons say


by Rich Daly EyeWorld Contributing Writer


miLOOP placement under anterior capsule

Bisecting nucleus in half
Source: Summit “Sam” Garg, MD

 

Surgeons have found a device that helps them surgically treat most cataract patients.
William Wiley, MD, has used the miLOOP (Carl Zeiss Meditec), an instrument with a super elastic, nitinol microfilament that wraps around a cataract for centripetal endocapsular nuclear disassembly, for about 2 years and in 500 eyes. The lenses ranged from clear to hypermature cataracts; he’s also used it in complex cases including small pupil and post-vitrectomy eyes.
Sumit “Sam” Garg, MD, has used miLOOP for about 1 year and generally reserves it for dense or brunescent cataracts. 
In dense lenses, “it assures a complete fragmentation of the lens, which can be complicated by posterior bridging fibers,” Dr. Garg said. “Also, because the lens is fragmented, I am able to use less phaco energy.”
Dr. Wiley agreed the device can divide the lens in multiple pieces in an atraumatic fashion allowing for more efficient cataract extraction with less phaco energy. He also cited easier lens fragment removal with less chance of capsule rupture or vitreous loss.
Susan MacDonald, MD, said another advantage the device has provided is in her instruction of surgeons who do not feel comfortable with phacoemulsification.
“It allows doing divide and conquer phaco without having to go through a lot of time learning divide and conquer and chopping,” Dr. MacDonald said. “It can be very simply a one-handed technique without using the phaco machine to do the divide and conquer.”
Dr. MacDonald said the device stemmed from an effort to find a technology that would be applicable in low-resource settings, such as where surgeons cannot afford a phacoemulsification machine. Such settings are where most of her miLOOP experience has come from, although she also has used it with phaco.
“I have used miLOOP on some of the most difficult cataracts on which I have ever operated,” Dr. MacDonald said. “These are mature, 5+, 6+ nuclear sclerotic cataracts that have been neglected in Tanzania.” She said the device helped her in such cases.

Area for caution

The type of cases where Dr. MacDonald has found cause for caution are those with zonular dehiscence that is significant or progressive, such as pseudoexfoliation patients who already have some zonular dialysis.
“In a patient that has had some traumatic dialysis, I am still able to use it,” Dr. MacDonald said.
The precaution on miLOOP’s use in cases of zonular weakness was common among surgeons treating such patients.
“It can be used on most any cataracts except cases with overt zonular weakness, where there is phacodonesis,” Dr. Wiley said. “That said, it can be used successfully in pseudoexfoliation cases that have not developed truly loose zonules.”
Dr. Wiley said in cases of loose zonules, passing the loop behind the lens may further weaken the zonules.
“This can be detected when engaging the loop prior to rotating the loop behind the lens,” Dr. Wiley said. “If the zonules are loose the miLOOP can be aborted without causing damage.”
Dr. MacDonald has found miLOOP is safer in pseudoexfoliation cases than the use of standard phacoemulsification.
“It is a gentler force when you are putting the miLOOP in and it’s not stretching the bag,” Dr. MacDonald said. “When you are cracking the nucleus, inward forces are being created, so miLOOP is not straining the zonules at all, and it is probably more zonular friendly than any divide and conquer or chopping technique.”
A challenge Dr. MacDonald has found with the device came when teaching surgeons who are hesitant to put something into the capsule and allow it to blindly find the way.
“That is the one piece of the learning curve to understand,” Dr. MacDonald said. “If you follow the directions, you’re not going to pierce the capsule. The material has been polished, and it is very smooth and is not going to rupture the capsule.”
The second issue is that sometimes when surgeons cut the nucleus and it is very dense, the lens tries to pop into the anterior chamber. Dr. MacDonald uses a second instrument in such cases to hold the nucleus back while she is cutting it.

FLACS use

Dr. Wiley said he has successfully used the miLOOP device with Zepto (Mynosys Cellular Devices), with the combination providing capsulotomy and lens fragmentation results that rival those provided by the use of a femtosecond laser.
“The miLOOP is more effective at lens fragmentation when compared to femto since it can bisect the lens from equator to equator, where the femto only fragments the lens in its central core,” Dr. Wiley said.
Dr. Garg does not think that the use of miLOOP in combination with an automated capsulotomy device will replace FLACS.
“With FLACS we are able to treat concomitant astigmatism,” Dr. Garg said. “Combining miLOOP with automated capsulotomy does not treat astigmatism.”
Drs. MacDonald and Wiley said they have used the miLOOP on all types of cataracts, although Dr. Garg was unsure the miLOOP would get around an extremely large cataract, but to date has not had any issues with respect to this.
In terms of anterior chamber prolapsed lens prevention, Dr. Garg generally stabilizes the lens with a second instrument (chopper/spatula) when performing a bisection.
If prolapse is not prevented, Dr. MacDonald puts viscoelastic into the eye, puts the lens back into the insertion guide and emulsifies.

About the doctors

Sumit “Sam” Garg, MD

Medical director
Gavin Herbert Eye Institute
University of California, Irvine

Susan MacDonald, MD
Associate professor
Tufts University School
of Medicine
Boston

William Wiley, MD
Assistant clinical professor
University Hospitals/Case Western Reserve
Cleveland

Relevant financial interests

Garg
: Carl Zeiss Meditec,
Johnson & Johnson Vision
MacDonald: Carl Zeiss Meditec, Perfect Lens
Wiley: Carl Zeiss Meditec

Contact information

Garg: gargs@uci.edu
MacDonald: susanmacdonaldeyecorps@gmail.com
Wiley: wiley@cle2020.com

Broad usefulness of miLOOP, surgeons say Broad usefulness of miLOOP, surgeons say
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