September 2020

CATARACT

Skill Focus
Pearls for injecting single-piece IOLs


by Ellen Stodola Editorial Co-Director




Using a single-handed injector while fixating the globe with a second instrument provides excellent visualization of the anterior capsule leaflet, ensuring placement of the IOL in the bag during injection.
Source: John Davidson, MD


A second instrument is placed through the sideport incision 90 degrees away from the main incision to stabilize the eye as the IOL injector is inserted.

Under continuous irrigation, the I/A tip is positioned slightly under the optic-haptic junction in order to lift and push the stuck haptic off the optic.


The I/A tip is slid under the optic, which is tilted and rotated 90 degrees within the capsular bag. This maneuver enables direct evacuation of all the OVD from within the capsular bag and ensures both haptics are within the capsular bag.
Source (all): D. Brian Kim, MD

To liberate a stuck haptic, apply centrifugal pressure in the X-Y plane of the optic to the back of the haptic tip with the I/A needle tip.
Source: John Davidson, MD

When preparing to inject a single- piece IOL, there are several potential issues that may arise during the process. Experts discussed some of these and how they routinely handle them.

What’s the best way to stabilize the eye during injection? Do you prefer twist injectors or push injectors?

According to D. Brian Kim, MD, the best way to stabilize the eye is to use a second instrument inside the sideport incision to provide countertraction to inject the IOL. The sideport is ideal because it is about 90 degrees away from the main incision and allows him to move the eye to assist with IOL injection. “I don’t recommend grasping the limbal tissue with 0.12 forceps since this could cause trauma,” Dr. Kim said.
Dr. Kim thinks surgeons make decisions based on which IOL they prefer, not which injector they prefer. In addition, some surgeons may not have a choice if the ASC or hospital only offers certain IOLs.
John Davidson, MD, noted that he has preferred the single-handed injector to the two-handed screw-type twist injector for nearly 20 years because the single-handed injector allows him to stabilize the eye with the non-dominant hand with a second instrument in the secondary incision. This keeps the eye in the primary position while you’re injecting the lens, he said, and gives control over the eye. You can watch the lens glide under the nasal leaflet of the anterior capsule, ensuring placement in the bag.
With the two-handed injector, Dr. Davidson said, you can’t stabilize the eye and end up having to push the globe nasally and often cannot visualize delivery of the lens in the bag, which is especially important in small pupil cases.
Robin Vann, MD, said stabilizing the eye depends on the kind of IOL injector being used. He has experience with the Alcon UltraSert.
The plunger is advanced best with the thumb, he said, but this can also induce torque. “I’ve found using a second instrument in my sideport incision helps stabilize the eye from the torque motion when I use my thumb to advance the plunger for injecting it into the eye,” he said.
Discussing different injector types, Dr. Vann said the push injector is nice, but if thumb-driven, he doesn’t like the torque. “From a stabilization standpoint and ability to get the lens into the eye as easily as possible, I prefer a twist injector,” Dr. Vann said.
He noted that the twist injector plunger advancement doesn’t come preloaded in the monofocal lens that he prefers, so that’s why he often uses the push injector. Alcon has a preloaded injector, AutonoMe, that advances the IOL plunger by pressing a knob on the injector, giving it the same insertion feel of a twist type injector without the torque of manual thumb advancement, Dr. Vann said. This injector is not available in the U.S. though.

What if the trailing haptic becomes trapped between the plunger and the cartridge? If the haptic becomes stuck to the optic?

Dr. Davidson uses his non-dominant hand to stabilize the injector where the cartridge is mounted and takes his dominant hand and twists with a wiggle motion on the plunger as he’s withdrawing the plunger, hoping to loosen the plunger from the optic. He doesn’t come out of the eye with the injector.
Dr. Davidson discussed what to do if the haptic is stuck to the optic. “A lot of surgeons will pinch the haptic with forceps, but this risks immediate flat chamber or use of additional OVD,” he said. Dr. Davidson said he prefers to take the tip of the I/A needle and nudge the haptic in the plane of the optic peripherally, which usually breaks the adhesion.
Dr. Vann hasn’t often had a problem with a trailing haptic stuck to the plunger. If it gets stuck on the optic, he said the I/A handpiece can apply suction to the area of the haptic that’s stuck to the optic. “That will often free it up to get it to expand and reshape itself to normal configuration,” he said.
If the haptic becomes trapped between the plunger and cartridge, Dr. Kim has used an internal approach with a second instrument through the sideport incision to bluntly tease the haptic off the plunger. If this doesn’t work, he’ll partially withdraw the injector to expose the stuck portion of the haptic, using forceps to free it.
If the IOL is completely in the eye and the haptic is stuck to the optic, Dr. Kim’s favorite technique is to use the I/A handpiece to gently push or lift the haptic off the optic. “I do this with the irrigation fluid turned on since it’s easier to manipulate a firm globe,” he said. If this doesn’t work, a second instrument with the I/A tip can apply opposing forces. With the I/A tip, he lifts up from under the haptic and pushes down on the optic with the cannula.

How do you avoid IOL trauma?

To avoid trauma to the IOL, for preloaded injectors, Dr. Vann said to make sure to use a lot of viscoelastic in the cartridge before advancing. Before the plunger meets the haptic, look closely to make sure it’s advancing in the proper plane so you’re not kinking or traumatizing the implant with the plunger advancing over top or down below the optic, he added. Inside the eye, once you’ve injected it, Dr. Vann tries to have his second instrument away from the optic.
Dr. Davidson said he routinely checks the folding forceps under the microscope to make sure they don’t have any metal burrs on them that could scratch the lens. He instructs technicians to never handle the optic. It’s necessary to touch the optic when folding it in the cartridge, but when pulling it out of the case and handling it any other time, grab by the haptics, he said.

How do you insert a single-piece acrylic IOL with an anterior capsular tear? Would you put in a single-piece with a posterior capsule tear?

It is safe to place a single-piece acrylic IOL in a bag with an isolated anterior capsule tear, Dr. Kim said. The key is to rotate the haptics within the bag so they are perpendicular to the tear, ensuring the IOL remains well centered.
In-the-bag single-piece acrylic IOLs should be avoided in the setting of posterior capsule tears for any defects bigger than the IOL optic. They should also be avoided in bags with any sized peripheral posterior capsule defect since the haptic can slip through the defect and lead to IOL dislocation. Small, fairly central posterior capsule tears can safely hold a single-piece acrylic IOL. “An even better strategy would be to perform a posterior continuous curvilinear capsulorhexis to turn the tear into a stable round hole, which is unlikely to tear out,” Dr. Kim said.
Dr. Davidson said he prefers to align haptics 90 degrees away from anterior capsule tear because putting the haptic at the tear may cause undue stress at the equator that could cause the tear to run to the posterior capsule. If there’s a posterior capsular tear that’s somewhat linear, you can still get a one-piece lens in the bag most of the time, as long as the haptics are 90 degrees to the tear, Dr. Davidson said.
If there is an anterior capsule tear, Dr. Vann uses a single-piece IOL, injecting into the anterior chamber and trying to depress the optic underneath the capsular bag, tucking the haptic with the second instrument.

Strategy for removing OVD from behind the IOL?

Dr. Davidson usually manipulates and rotates the IOL with the I/A handpiece. He continues to deliver the posterior trailing haptics with the I/A handpiece and does not use a second instrument through the sideport. “I’m already evacuating the viscoelastic before the lens is fully unfolded,” he said. “I don’t have to intentionally lift the edge of the IOL to evacuate the OVD from behind it because the OVD is gone before the lens is unfolded.”
Dr. Kim said he does not advise relying on indirect means to remove OVD from behind the IOL. You don’t want to leave OVD inside the bag because it can cause capsular bag distention syndrome and a myopic refractive surprise from the anteriorly displaced IOL.
The best way to remove OVD is to get it directly by going behind the IOL and removing it from within the bag. This way you have no doubt that all the OVD is out of the bag. Single-piece acrylic IOLs are malleable and easy to tilt to go under the optic with the I/A tip. His technique is to go under the IOL, then tilt and rotate 90 degrees. Tilting the optic allows you to get into the bag without putting stress on the zonules and rotating it helps to ensure both haptics are within the bag.

About the doctors

John Davidson, MD

Director of refractive/
lens replacement surgery
Miramar Eye Specialists
Medical Group
Ventura, California

D. Brian Kim, MD
Partner
Professional Eye Associates
Clinical assistant professor
of ophthalmology
Medical College of Georgia
Augusta, Georgia

Robin Vann, MD
Medical director
Duke Eye Center Operating Rooms
Durham, North Carolina

Relevant disclosures
Davidson
: Alcon
Kim: None
Vann: Alcon

Contact
Davidson
: doctorjohn@johndavidsonmd.com
Kim: kim@professionaleye.com
Vann: Robin.Vann@duke.edu

How much larger than the cartridge should the corneal incision be?

Dr. Kim provided general guidelines for the Alcon SN60WF AcrySof IOL using the Monarch injector system, A being the largest cartridge and D being the smallest:
D cartridge: 2.2–2.6 incision
C cartridge: 2.6–3.0 incision
B cartridge: 3.0–3.2 incision
A cartridge: 3.2–3.4 incision
The only exception to this rule, he said, is for high-powered IOLs 28 D or greater, which require the B cartridge. Since these high powered IOLs are thicker, the surgeon will need to widen the incision if it is less than 3.0 mm.
Dr. Kim makes a 2.6-mm incision and primarily uses a D cartridge. “Every surgeon should consult the manufacturer’s recommendations and allow the phaco rep to give some guidance when choosing the best cartridge for a given incision size,” he said.
 

Where should you direct the IOL when inserting?

The initial step with IOL insertion is complete expansion of the capsular bag with OVD, Dr. Kim said. As the cartridge is inserted, the single-piece acrylic IOL should be angled toward the capsular bag with the leading haptic injected into the bag while the remainder of the IOL is left in the anterior chamber, he said. The surgeon can then elect to use a second instrument to position the remainder of the IOL in the bag. “I prefer to use the I/A handpiece to manipulate the IOL into the bag because 1.) I need to irrigate the OVD out anyway, and 2.) I can take advantage of the irrigating fluid to inflate the capsular bag, which creates more room for me to position the IOL in the bag,”
Dr. Kim said. “This stepwise approach also enables me to carefully inspect the IOL for scratches or defects, ensures the IOL is oriented properly (leading haptic points left), and allows me the time to ensure both haptics are released from the optic before the entire IOL is inserted within the bag.”

Pearls for injecting single-piece IOLs Pearls for injecting single-piece IOLs
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2020-08-31T09:54:17Z
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