Cataract: YES Connect: Opening Doors
Winter 2025

by Ellen Stodola
Editorial Co-Director

For this YES Connect column, we invited Brandon Baartman, MD, and Kamran Riaz, MD, to share their experiences and insights on pars plana approach anterior vitrectomy. As anterior segment surgeries become increasingly complex, many surgeons are incorporating this technique into their skillsets for situations where thorough vitreous removal is essential. In recent years, the term “middle segment surgery” has gained traction to describe anterior segment surgeons who access the posterior chamber through the pars plana for secondary lens fixation and vitrectomy. Sessions on middle segment surgery are now regularly featured at national and international academic conferences and serve as valuable resources for those whose practices involve complex anterior segment surgery. It is important to note that surgeons—both early-career and experienced—should always operate within the bounds of their training and comfort, seeking mentorship when undertaking these advanced procedures for the first time.

—Brenton Finklea, MD
YES Connect Guest Editor

The performance of a pars plana anterior vitrectomy can be an essential skill in select circumstances. Brandon Baartman, MD, and Kamran Riaz, MD, discussed when this approach may best be utilized, benefits of the approach, and other nuances. 

Dr. Riaz said that the most common scenario to use anterior vitrectomy from the pars plana is following a PC tear with vitreous loss into the anterior chamber, which occurs during routine cataract surgery. “Traditionally, we would use the bimanual anterior vitrector through two paracenteses incisions,” he said. “In recent years, many of us have shifted to using the anterior vitrector in these situations to enter the pars plana. The pars plana approach is preferred, in my opinion, because it allows the surgeon to cut the vitreous from behind the IOL-zonule complex, which allows the vitreous to fall back.” He added that this allows the surgeon to clear the AC/pupil/capsular bag to create a stable anterior chamber environment, reduce vitreous traction, and safely place an IOL (either one-piece if the PC tear is focal and central or three-piece in the sulcus with or without optic capture). 

The other scenario in which surgeons often utilize this technique is when performing secondary IOL placement and exchanges (e.g., unhappy advanced-technology IOL patients, especially if a YAG has been performed), Dr. Riaz said. “In these cases, vitreous may be already in the AC, may be causing some of the pseudophakic unhappiness, or may prolapse anteriorly when trying to remove the IOL. Therefore, a pars plana approach can create a safe/clean AC for IOL removal/replacement, provide a more controlled surgical field during IOL replacement, improve long-term stability of the new IOL by making sure the optic/haptics are supported in a vitreous-free environment, and reduce vitreous incarceration around the haptics or AC structures that can lead to postoperative CME/retinal tears.” He added that many anterior segment surgeons are shifting to a posterior approach thanks to a growing body of knowledge demonstrating safety and efficacy.  “The only time I still do the ‘traditional’ anterior vitrectomy is if I’m doing [scleral-fixated] IOL surgery in a patient who has already been vitrectomized but now has aphakia or a dislocated IOL,” he said. “I’ve found, in these cases, there is often still some vitreous left near the IOL-iris, so the bimanual anterior vitrectomy approach works well here.”

Many cases where the need for vitrectomy arises can be managed by either the anterior or posterior approach, Dr. Baartman said. “Cases necessitating vitrectomy are usually vitreous prolapse from a ruptured capsular bag or damaged or absent zonular complex,” he said. “Generally speaking, if vitreous is presenting unexpectedly during an otherwise routine case, I favor the simplicity of a bimanual limbal approach to removing what is usually a limited amount of vitreous.”

Dr. Baartman gave the example of a posterior polar cataract where during cortex removal around the posterior plaque, a posterior capsular opening is encountered. He said that many times, this can be managed without vitreous loss, but if there is vitreous present in the anterior chamber after lens placement, an anterior approach is sufficient. “For cases that are known to require an anterior vitrectomy, such as an open capsule IOL exchange or a dislocated lens-bag complex in a patient without prior vitrectomy, I would favor a pars plana approach for more control and a more complete anterior vitrectomy,” he said.

Benefits of the pars plana approach

Dr. Baartman noted several benefits to a pars plana vitrectomy for the anterior segment surgeon. “First, you’re accessing the vitreous cavity directly, and the direction of travel of the vitreous during vitrectomy is posterior instead of anterior. I like the physiology of anterior infusion and posterior vitrectomy. Presumably, this would create less traction on a vitreous body still adherent to the retina.”

Another benefit he noted is a more complete vitrectomy, which may be preferred when considering sutured lens fixation or intrascleral haptic fixation. 

“I would also consider a posterior approach beneficial when, in the example of an open bag IOL exchange, you can preempt vitreous loss by accessing the vitreous cavity prior to IOL removal and have more control,” he said. “Bonus points for this approach are when you are using a trocar and are in need of IOP maintenance, you can use posterior infusion once the vitrectomy is complete and keep the peri-limbal space free from a bulky AC maintainer.”

Dr. Riaz also finds that the anterior to posterior fluid flow is a benefit of the pars plana approach. It pulls vitreous posteriorly, away from the corneal wounds and allows the vitreous to naturally fall back into the posterior cavity, he said, which in turn helps to make sure the unwanted blurry vision or “pupil peaking,” because of vitreous still present in the AC, doesn’t occur.

Another benefit, he said, is a stable anterior chamber. The infusion through the limbus or pars plana maintains a formed chamber, minimizing iris prolapse and wound stress.

This also offers clearer visualization with less turbulence and less risk of corneal endothelial trauma compared to limbal vitrectomy because the vitrector isn’t close to the cornea.

Pars plana anterior vitrectomy also offers the advantage of long-term safety, Dr. Riaz said. It decreases the risk of retinal breaks, CME, and other vitreoretinal sequelae from vitreous incarceration.

Finally, he said that one “bonus benefit” is it can get rid of floaters that many patients have that cause visual problems. 

Skills/techniques 

Dr. Riaz said the biggest skill needed is to be able to enter the pars plana safely and effectively. He thinks this is easier for younger surgeons who have done many pars plana injections for retinal pathology during training. He added that comfort with pars plana entry anatomy (3.5 mm posterior to the limbus in pseudophakic/aphakic eyes) is also important. “Use a caliper and measurement; don’t just ‘eyeball’ the 3.5 mm distance,” he said. 

Surgeons should also plan to use a trocar- cannula system for safe access. “This is probably the biggest thing that makes surgeons hesitant,” Dr. Riaz said. He uses a 23 g trocar but added that 25 g and 27 g are available. He prefers the 23 g trocar because the tubing connects seamlessly with his phaco machine, eliminating the need for a standalone vitrectomy machine. 

Placing the trocar is a “new skill” for veteran cataract surgeons, Dr. Riaz said, but more recently graduated surgeons have been placing trocars during residency, so they are comfortable with the angled approach to ensure the trocar is placed safely and correctly. “Some surgeons don’t suture these incisions, but I always feel more comfortable suturing my sclerotomies, especially when I do an SFIOL surgery, because the last thing I want is hypotony, which can affect the IOL position, cause corneal edema, cause CME, etc.”

Dr. Riaz also noted that surgeons should review and be comfortable with vitrector settings for this approach: high cut rate and low aspiration to minimize vitreous traction for vitreous removal. He uses the “I/A cut” settings when removing cortex. 

An anterior chamber maintainer or infusion through the pars plana is key for chamber stability. Additionally, Dr. Riaz noted that triamcinolone can be very helpful in confirming that all vitreous strands have been cleared before IOL placement.

Triamcinolone is especially valuable during pars plana or anterior vitrectomy because it provides high-contrast visualization of residual vitreous strands that would otherwise be subtle or invisible, Dr. Riaz said. The effect arises from the insoluble white triamcinolone crystals physically binding to the loosely organized collagen fibrils of the vitreous face. In routine cases, undiluted triamcinolone (40 mg/mL) can be used directly; however, many surgeons prefer to decant, filter, or lightly dilute the suspension to remove excess vehicle and reduce particulate clumping. A gentle rinse with balanced salt solution maintains adequate particle density while minimizing large aggregates that can obscure the surgical field. Even minimal volumes (0.05–0.1 mL) disperse efficiently in the anterior segment and evenly coat the vitreous scaffold, he said.

Meaningful differences exist between standard triamcinolone formulations and preservative-free preparations such as Triesence (Harrow), Dr. Riaz continued. Kenalog (Bristol-Myers Squibb) contains benzyl alcohol, which may cause transient postoperative inflammation or endothelial irritation if retained within the anterior chamber. Nevertheless, when injected into the pars plana sparingly and thoroughly irrigated at the end of the case, Kenalog remains safe and highly effective for vitreous staining. Triesence, being preservative-free, eliminates concerns about benzyl alcohol, exhibits a more uniform particle-size distribution, and provides an exceptionally fine particulate coating of the anterior cortical vitreous. These are advantages some surgeons find particularly helpful in complex cases or when visualization is compromised. Cost, availability, and practice setting remain practical considerations when choosing between formulations, he said.

Several technique refinements can enhance both visualization and safety, Dr. Riaz said. After triamcinolone injection, a brief pause allows the particles to settle and coat the vitreous uniformly before continuing vitrectomy. Many surgeons begin with a high-cut, low-vacuum setting to remove the obvious anterior vitreous and allow any remaining strands to fall posteriorly. Switching to higher aspiration with a lower cut rate helps identify and remove subtle strands without transmitting traction to the vitreous base. Alternating between these settings confirms that no residual vitreous remains engaged with the capsule, iris, or wounds. An intraocular miotic, such as acetylcholine or carbachol, can help ensure a round, stable pupil and expose peripheral vitreous tags. Repeat triamcinolone may be instilled as needed to verify complete clearance. At the conclusion, a meticulous irrigation/aspiration sweep removes residual particulate material from the anterior chamber, reducing the risk of postoperative pressure elevation, inflammation, or visual disturbances, he said. “A good rule is cut, don’t pull. Always cut vitreous strands rather than aspirating them out,” he said. 

Always make an iridectomy (you can use the vitrector for this) when placing an IOL in the sulcus or SFIOL fixation to prevent pupillary block issues, Dr. Riaz added.

To be able to utilize the pars plana technique, Dr. Baartman said it’s important to know the anatomy, which he said is measured at 3.5 mm posterior to the limbus, along with creation of a peritomy and suturing of the resultant sclerostomy if using a stab incision approach. “I prefer the use of a valved trocar, which if placed at the appropriate bevel can be used without the need for a suture,” he said. 

Potential risks

Dr. Baartman also offered some important tips to keep in mind. Anytime you access the pars plana via a sclerotomy, it’s a good idea to aim your blade (or trocar) towards the center of the eye to create the incision. Make sure you visualize the tip of the trocar to ensure it is not covered by tissue before using it to access the eye with other instruments, he said, which will ensure the sclerotomy is complete.  

“It’s also good practice to perform vitrectomy as you are entering and exiting the eye via the sclerotomy so as not to drag vitreous,” he said. “A leaking sclerotomy is possible, even with a transconjunctival trocar, so ensure it’s sealed before closing up the case to avoid hypotony or an inadvertent bleb.”

Dr. Baartman added that cases with vitreous loss are also known to have a higher risk of endophthalmitis. “If you’re not sure, pass a suture to close the sclerotomy,” he said. 

There’s also always a potential risk of retinal detachment or choroidal hemorrhage in these complex eyes, so mind the red reflex during the case and always plan a dilated eye exam within the first week after the procedure. 

Dr. Riaz said to watch out for retinal breaks or detachment if the sclerotomy is misplaced too far posterior, or if vitreous traction is induced. You could also get iatrogenic lens or iris injury if the entry site is too anterior or if instruments are misdirected, he said. If the trocar is not properly placed, there may be a risk of hypotony or wound leak.  

He added that eyes with compromised posterior segment status (like prior RD or vitrectomy) may warrant extra caution and in rare cases, referral to a vitreoretinal colleague for a complete posterior vitrectomy.

Dr. Riaz also noted the learning curve. “Surgeons unfamiliar with pars plana anatomy or vitreoretinal maneuvers should practice before using it in a high-stress complication scenario,” he said. “Many conferences now have dedicated wet labs so surgeons can learn these techniques quite easily.” 

For cataract surgeons, pars plana anterior vitrectomy is a powerful tool to manage vitreous loss more safely and physiologically, Dr. Riaz said. “With the right tools and basic comfort in pars plana entry, it can improve visualization, reduce traction, and ultimately lead to better IOL and retinal outcomes,” he said. “I think all cataract surgeons should learn this skill because it is, in my opinion, a necessary skill for the modern anterior segment surgeon to master. We are having to use it for planned cases regularly and unplanned cases rarely.” 

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About the physicians

Brandon Baartman, MD
Vance Thompson Vision
Omaha, Nebraska

Kamran Riaz, MD
Clinical Professor
Thelma Gaylord Endowed Chair in Ophthalmology
Vice Chair for Clinical Research
Dean McGee Eye Institute
Oklahoma City, Oklahoma

Relevant disclosures

Baartman: None 
Riaz: None

Contact 

Baartman: brandon.baartman@vancethompsonvision.com
Riaz: Kamran-Riaz@dmei.org