April 2019

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Presentation Spotlight
Fundamentals of anterior vitrectomy for cataract surgeons


by Ellen Stodola EyeWorld Senior Writer/ Meetings Editor


This patient underwent an IOL exchange following a late dislocation of the capsular bag in her left eye. The eye has a superior bleb because of long-standing glaucoma. A standard two-port anterior vitrectomy was performed to clear vitreous from the anterior segment. A high cut rate of 4,000 cuts/minute was selected.
Source: Kevin M. Miller, MD

 
During a session at the 2019 Hawaiian Eye Meeting, Kevin M. Miller, MD, shared some of the fundamentals of anterior vitrectomy for cataract surgeons.
The primary goal of anterior vitrectomy is to remove vitreous gel, he said. There are secondary goals, which can include relieving vitreous incarceration in corneal and scleral incisions, eliminating peaking of the pupil, removing any remaining lens material, removing vitreous floaters, removing some or all of the lens capsule, and removing an IOL or other devices.
The most important thing, he said, is to keep vitreous traction to an absolute minimum. You can’t cut the vitreous without pulling a little, but you don’t want to pull a lot.
Dr. Miller added that a poorly performed vitrectomy can cause a peaked pupil, a decentered lens, or wound leak.
Dr. Miller said to separate the irrigation/pressurization line from the cut/aspiration line. Use trocars if you will be in and out of the eye several times, and place the cut/aspiration port in the vitreous cavity. This can be done using a limbal approach or pars plana approach.
He added that you don’t want to pull vitreous into the anterior chamber because this enlarges posterior capsule tears and places greater traction on the vitreous.
The irrigation/pressurization line can be placed in the anterior chamber or in the vitreous cavity. Dr. Miller said that some surgeons like an anterior chamber maintainer. If placed through a sclerotomy, confirm that the infusion port is inside the vitreous cavity and not under the choroid before turning on irrigation.
It’s helpful to use triamcinolone to stain the vitreous if you are having trouble visualizing it, Dr. Miller said. Triamcinolone will adhere to OVD, so be aware of the difference. Additionally, residual triamcinolone left in the eye helps quiet postoperative inflammation. On the down side, triamcinolone adds to floaters after surgery.
Dr. Miller stressed the importance of knowing the difference between vitrectomy modes. Position 1 is irrigate/pressurize, but positions 2 and 3 can vary. The first mode he noted was:
1. Irrigate/pressurize
2. Cut
3. Aspirate
He said to use this mode to cut and remove vitreous and to be sure to advance the foot pedal into position 3 (otherwise the vitreous will not be removed). The second mode he noted was:
1. Irrigate/pressurize
2. Aspirate
3. Cut
He said to use this mode to remove cortex and capsule remnants once the vitreous in the area has been cleared; never aspirate the vitreous without cutting it.
When performing a vitrectomy, always use the highest cutting rate available on a machine. Don’t make large movements with the probe when it is in contact with the vitreous, and always turn the port away from the iris when you are near it, otherwise the iris will jump into it.
Dr. Miller added that after a vitrectomy, the eye is often soft, and the incisions will leak more easily. Use sutures or sealants to close incisions as needed, and inject a miotic to constrict the pupil if an IOL is placed in the ciliary sulcus. He also noted that the eye is more prone to develop cystoid macular edema and suggested treating aggressively with anti-inflammatory agents.
 

About the doctor
Kevin M. Miller, MD

Kolokotrones Chair in Ophthalmology
Chief of the Cataract and Refractive Surgery Division
David Geffen
School of Medicine University of California, Los Angeles

Financial interests
Miller: Alcon, Johnson & Johnson Vision

Contact information
Miller
: kmiller@ucla.edu

Fundamentals of anterior vitrectomy for cataract surgeons Fundamentals of anterior vitrectomy for cataract surgeons
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2019-04-05T08:25:01Z
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